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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Noopy on May 10, 2020, 09:43:28 pm

Title: Transistors - die pictures
Post by: Noopy on May 10, 2020, 09:43:28 pm
How about a transistor-die-picture-topic?  :)

I have collected some here:

https://www.richis-lab.de/Transistoren.htm (https://www.richis-lab.de/Transistoren.htm)


And I just have to show you this one:

(https://www.richis-lab.de/images/Transistoren/02x09.gif)

You see the breakdown of the KD501-base-emitter-junction with increasing current.  8) ;D


(https://www.richis-lab.de/images/Transistoren/02x07.jpg)

Does anybody know why Tesla integrated this step at the edge of the die?
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 10, 2020, 10:01:19 pm
The BE breakdown video is great ?

I'm working on a PHD where this effect plays a role. May I use your video in my thesis ?

Just speculating, is this a MESA part ?
Title: Re: Transistors - die pictures
Post by: Noopy on May 11, 2020, 03:10:13 am
The BE breakdown video is great ?

I'm working on a PHD where this effect plays a role. May I use your video in my thesis ?

Thanks!
Of course you can use it in your PHD.
If you need something special (higher resolution, different angle,...) just tell me.


Just speculating, is this a MESA part ?

Sounds reasonable!  :-+
Title: Re: Transistors - die pictures
Post by: Miyuki on May 11, 2020, 09:31:49 am
Just speculating, is this a MESA part ?

Sounds reasonable!  :-+

Looks exactly as on book drawings
[attachimg=1]
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 11, 2020, 03:14:55 pm
... just a question - is the 2N2222A also emitting light in BE breakdown ?

 regards
  Wolfgang
Title: Re: Transistors - die pictures
Post by: exe on May 11, 2020, 03:28:34 pm
Is it possible to check tip3055 and tip2955 from onsemi and st? I'm willing to sponsor this. They are in plastic enclosure, to-264 or to-247.
Title: Re: Transistors - die pictures
Post by: Noopy on May 11, 2020, 03:53:05 pm
... just a question - is the 2N2222A also emitting light in BE breakdown ?

 regards
  Wolfgang

I´m pretty sure every bipolar transistor has the same glowing.
I want to do this again with a smaller transistor. Let´s see what I have on my bench.

...I have taken new pictures of the BE-breakdown will upload them today…


Is it possible to check tip3055 and tip2955 from onsemi and st? I'm willing to sponsor this. They are in plastic enclosure, to-264 or to-247.

In principle that´s no problem:

(https://www.richis-lab.de/images/decap-ofen/22.jpg)
https://www.richis-lab.de/decap-ofen.htm (https://www.richis-lab.de/decap-ofen.htm)
 ;D

My success rate is something around 95%. Only very few package fail in decapping but there are some.
And it takes some days. After all it´s only a hobby.  :-/O
If that´s ok for you feel free to send me the parts.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on May 11, 2020, 07:37:50 pm
I have uploaded a new row of pictures including the current values:
https://www.richis-lab.de/Bipolar02.htm (https://www.richis-lab.de/Bipolar02.htm)

One interesting effect is the positive temperature coefficient of the breakdown voltage (Z-diode with Vbr=10V). If you connect a voltage at B-E that is just high enough to let it break down and then increase the current the B-E-junction suddenly gets non conductive again. => Physics! :-+ ;D
Title: Re: Transistors - die pictures
Post by: mawyatt on May 12, 2020, 02:46:49 pm
I have uploaded a new row of pictures including the current values:
https://www.richis-lab.de/Bipolar02.htm (https://www.richis-lab.de/Bipolar02.htm)

One interesting effect is the positive temperature coefficient of the breakdown voltage (Z-diode with Vbr=10V). If you connect a voltage at B-E that is just high enough to let it break down and then increase the current the B-E-junction suddenly gets non conductive again. => Physics! :-+ ;D

Very interesting results with the optical output from the reversed breakdown EB junction!! 8) Also like the method you've developed to de-encapsulate ICs based upon "burning" off the epoxy, very clever :-+

An interesting effect on some bipolar transistors when used with EB junction reversed biased in this type behavior where the plot of voltage vs. current has a region of negative slope when entering breakdown, or dV/dI is negative, thus negative resistance. This is the type of behavior of a avalanche or tunnel diode.

One can build a simple "relaxation oscillator" by using a large (~100K) resistor to supply a higher than breakdown voltage (usually >10 volts) to the Emitter junction of an NPN transistor. The base is ground and collector open (also try a connect to collector ground and leave the base open), a capacitor (10nF) shunting the EB junction to ground. With a scope you can observe a sawtooth relaxation waveform across the EB junction as you adjust the supply voltage. This waveform is caused by the charging of the capacitor with the RC time constant, then a rapid discharge as the junction enters the negative resistance region, then a repeat of this cycle.

The late Jim Williams (brilliant analog engineer, RIP) discussed at the ISSCC awhile back (I had a brief private discussion with him) how he designed a cheap voltage reference using a small NPN transistor with the EB junction operated in breakdown which produces a positive TC, then the base was left open and the collector grounded. This would forward bias the base to collector diode would produce the negative TC compensating the positive TC of the reversed breakdown of the EB junction. This went into production only to find that the composite transistor based reference was oscillating using the decoupling capacitor and resistor bias!!

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on May 12, 2020, 04:47:28 pm
Very interesting results with the optical output from the reversed breakdown EB junction!! 8)

I did this also with the famous LTZ1000 to identify where the different junctions are:

(https://richis-lab.de/images/REF01/01_11.jpg)
(https://richis-lab.de/images/REF01/01_12.jpg)

https://richis-lab.de/REF03.htm (https://richis-lab.de/REF03.htm)


Also like the method you've developed to de-encapsulate ICs based upon "burning" off the epoxy, very clever :-+

It´s a simple and much less dangerous way than working with ultra special solvents or hot concentrated acids. It works quite well and very fast!  :-+


An interesting effect on some bipolar transistors when used with EB junction reversed biased in this type behavior where the plot of voltage vs. current has a region of negative slope when entering breakdown, or dV/dI is negative, thus negative resistance. This is the type of behavior of a avalanche or tunnel diode.
...

I think I have heard of that somewhere...  :-+


The late Jim Williams (brilliant analog engineer, RIP) discussed at the ISSCC awhile back (I had a brief private discussion with him) how he designed a cheap voltage reference using a small NPN transistor with the EB junction operated in breakdown which produces a positive TC, then the base was left open and the collector grounded. This would forward bias the base to collector diode would produce the negative TC compensative the positive TC of the reversed breakdown of the EB junction. This went into production only to find that the composite transistor based reference was oscillating using the decoupling capacitor and resistor bias!!

Best,

You had a private discussion with Jim Williams? Very cool!  8)
Title: Re: Transistors - die pictures
Post by: Noopy on May 12, 2020, 05:28:07 pm
Today I have a Germanium-Transistor for you, a Philips AU301:

https://www.richis-lab.de/Bipolar03.htm (https://www.richis-lab.de/Bipolar03.htm)


(https://www.richis-lab.de/images/transistoren/03x04.jpg)


It´s an alloy transistor. The combination of power and alloy transistor leads to an interesting design...
Title: Re: Transistors - die pictures
Post by: Noopy on May 12, 2020, 08:43:38 pm
I have uploaded a new row of pictures including the current values:
https://www.richis-lab.de/Bipolar02.htm (https://www.richis-lab.de/Bipolar02.htm)

Now with animated GIF:

(https://www.richis-lab.de/images/Transistoren/02x12.gif)

 8) ;D 8)
Title: Re: Transistors - die pictures
Post by: exe on May 12, 2020, 09:41:40 pm
There are spots that light up first. Are those the hot spots responsible for secondary breakdown?
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 12, 2020, 09:49:21 pm
No. Secondary breakdown occurs at the BC junction, not at BE.
Title: Re: Transistors - die pictures
Post by: mawyatt on May 13, 2020, 03:00:02 am

You had a private discussion with Jim Williams? Very cool!  8)

Yes, we talked briefly over coffee at the ISSCC in 2011 (Feb) and Jim passed away a few months later  :(

 Also had the pleasure of meeting and discussing things with Larry Nagle (Berkeley SPICE Author) at the ISSCC, a colleague worked with Larry at Bell Labs. Didn't make the ISSCC this year though, too risky.

BTW what current did you run thru the LTZ1000 to see the optical output? Would really like to get an LTZ1000, but they've become very expensive lately :-\

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on May 13, 2020, 03:19:42 am
BTW what current did you run thru the LTZ1000 to see the optical output? Would really like to get an LTZ1000, but they've become very expensive lately :-\

I believe it was something around 10mA or 20mA back in the day.
The LTZ1000 was a noisy one a voltnut donated to me.
...I have a AD1139 on the bench…  8)
Title: Re: Transistors - die pictures
Post by: Noopy on May 13, 2020, 07:43:04 pm
... just a question - is the 2N2222A also emitting light in BE breakdown ?

Coincidentally I had a 2N2222A in my inbox.  ;D


(https://www.richis-lab.de/images/transistoren/04x05.jpg)

As expected the BE-junction glows too.


I then killed the 2N2222A and made a short video.  >:D

(https://www.richis-lab.de/images/transistoren/04x09.png)


You can identify the route of destruction:

(https://www.richis-lab.de/images/transistoren/04x09.jpg)

My Interpretation:
1) First breakdown destruction of the BE-junction.
2) Base-Electrode melts and cuts the current.
3) Second destruction of the BE-junction.
4) Base-metal melts further to the bondpad.
5) Last connection is disrupted with a bright arc.
Interesting...  :popcorn:


More pictures here:

https://www.richis-lab.de/Bipolar04.htm (https://www.richis-lab.de/Bipolar04.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 13, 2020, 10:54:33 pm
... just a question - is the 2N2222A also emitting light in BE breakdown ?

Coincidentally I had a 2N2222A in my inbox.  ;D


(https://www.richis-lab.de/images/transistoren/04x05.jpg)

As expected the BE-junction glows too.


I then killed the 2N2222A and made a short video.  >:D

(https://www.richis-lab.de/images/transistoren/04x09.png)


You can identify the route of destruction:

(https://www.richis-lab.de/images/transistoren/04x09.jpg)

My Interpretation:
1) First breakdown destruction of the BE-junction.
2) Base-Electrode melts and cuts the current.
3) Second destruction of the BE-junction.
4) Base-metal melts further to the bondpad.
5) Last connection is disrupted with a bright arc.
Interesting...  :popcorn:


More pictures here:

https://www.richis-lab.de/Bipolar04.htm (https://www.richis-lab.de/Bipolar04.htm)

 :popcorn:

Rich, just awesome, just what I need ! Thanks a lot !

Some questions:
- the video shows a very fast current increase. Did you run this with a current source ? Or is just the video too fast ?
- In my transistors, I see a noise curve very explainable by your KD503 video. First, only a few hotspots light up,
then more and more, until the whole area is bright. So noise *falls* with rising current. The 2N2222 seems to start almost immediately. Why ?
The Zener range is the same (> 7V), so it must be an avalanche mechanism.
- Do you want noise plots ? In case the 2N2222A behaves the same, they could be of interest.

Thanks again ! If you dont mind, I really want to give you an honourable mention in a paper I'm writing.
Title: Re: Transistors - die pictures
Post by: Noopy on May 14, 2020, 03:39:53 am
- the video shows a very fast current increase. Did you run this with a current source ? Or is just the video too fast ?

The bench supply is the weak spot of my lab.  :-X
I used a very cheap supply for this experiment. In the video I just cranked up the current limit to overload the 2N2222. I assume the current jumped up to something around 200mA, didn´t check that.
In the meantime I have some HP-supplies but I still have to integrate them into my bench...


- In my transistors, I see a noise curve very explainable by your KD503 video. First, only a few hotspots light up,
then more and more, until the whole area is bright. So noise *falls* with rising current. The 2N2222 seems to start almost immediately. Why ?
The Zener range is the same (> 7V), so it must be an avalanche mechanism.

Why? My supply!  ;D
It´s a pain in the ass to adjust the current limit around 10mA. The supply doesn´t even show smaller currents than 10mA. I had to meassure the current with my bench meter.
In the KD503 10mA is low enough to get the small little hotspots. In the 2N2222 with 10mA the current density is already high enough to light it up almost completely.
I have uploaded a new picture showing the glowing with lower current:

(https://www.richis-lab.de/images/Transistoren/04x11.jpg)

You can see the light is not uniform. With smaller currents I´m sure it would look like the KD501.

I observed the same effect with the 2N3055:
To get a uniform light in the big old ones you need a lot of current. They get pretty hot. In the newer small dies some ten mA are enough to get a nice light all over the place.


- Do you want noise plots ? In case the 2N2222A behaves the same, they could be of interest.

Of course! That would be very interesting!


Thanks again ! If you dont mind, I really want to give you an honourable mention in a paper I'm writing.

It would be an honour!  8)

Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 14, 2020, 03:47:54 am
I wonder if the glow pattern varies with charge state on the surface passivation (which is likely silica glass).  This would be hard to test; perhaps exposed metal surfaces could be insulated with an insulating film, then a conductive liquid (e.g. salt water) applied to control the surface electric field?  (Might need hundreds of volts, since the insulation will be so thick at this point.)

Tim
Title: Re: Transistors - die pictures
Post by: RoGeorge on May 14, 2020, 07:36:35 am
Why nobody put a photodiode inside to protect expensive power transistors?
Title: Re: Transistors - die pictures
Post by: Noopy on May 14, 2020, 09:23:56 am
I wonder if the glow pattern varies with charge state on the surface passivation (which is likely silica glass).  This would be hard to test; perhaps exposed metal surfaces could be insulated with an insulating film, then a conductive liquid (e.g. salt water) applied to control the surface electric field?  (Might need hundreds of volts, since the insulation will be so thick at this point.)

Tim

Possible but hard to test...  :-//


Why nobody put a photodiode inside to protect expensive power transistors?

In my view in real applications transistors rarely die because of base-emitter-breakdown.
Secondly you must be able to do something against the base-emitter-breakdown. Often base-emitter-breakdown occurs due to a bad design or a failure in an other circuit. It´s hard to compensate these things...
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 14, 2020, 10:46:30 am
Why nobody put a photodiode inside to protect expensive power transistors?

... its not a real world problem for power parts. Any useful design prevents this, e.g. by an antiparallel diode at the base. Furthermore, you need quite some current to kill those parts.
The problem is more with small transistors, where a BE breakdown even with small currents and for short times only degrades gain at low currents permanently.
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 14, 2020, 10:53:38 am
Hi Rich,

if you have no reliable constant current source you could try a normal power supply in constant voltage mode with a series resistor (or a pot) and a good multimeter in current mode. That should work.

Next week I could try to run this on a Keysight B2962 SMU.

Measured noise plot for 100uA, 1mA and 10mA is attached.

Best regards
  Wolfgang
Title: Re: Transistors - die pictures
Post by: Noopy on May 14, 2020, 11:44:31 am
Hi Wolfgang,

I just have to power up my HP6627A. That should be sufficient. But it has binding posts on the back so I need some kind of a connection panel first.

The bench supply I use at the moment is ok (with a Fluke 45) but it´s definitely no SMU to specify semiconducter properties.  :-/O

Thanks for the noise plots! Quite interesting!

Best regards,

Richard
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 14, 2020, 02:01:57 pm
Why nobody put a photodiode inside to protect expensive power transistors?

But they did!  C-B junction generates a small photocurrent; Widlar famously employed this trick to generate a few mV / uA negative say for biasing a single-supply op-amp's output so that it can go all the way through and below zero. :)

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 14, 2020, 02:19:26 pm
... Widlar used the trick to protect *power* transistors ?

I heard the story but never seen a practical Op amp that uses the effect. Curious !
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 14, 2020, 04:40:07 pm
Not to protect, of course, just that it's possible in a sense to build such a circuit around a normal device.  Obviously if you're using C-B as a photodiode, you can't very well also use it for delivering power to a load. ;D

Interesting consequence: when C-B is reverse biased (as normal) and E-B is avalanched, the same photocurrent flows C-B, which means C leakage increases.  Need low leakage?  Clamp that base voltage, say with a diode, or a zener/TVS with rating somewhat below Vebo.  Simple enough. :)

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 14, 2020, 06:43:35 pm
... tried this with a 2N2222A. When you set VCE=5V and then you let BE break down, collector current does not move.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 14, 2020, 07:54:33 pm
What magnitude?  Ic should be at least ~nA to start with; I would guess uA is reasonable to expect here?

If it doesn't actually go up, that's quite interesting.  Do you measure any negative voltage when it's open?

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 14, 2020, 07:59:50 pm
Keysight B2962 SMU starting with 10nA, IIRC.
Maybe you need more collector voltage than the 5V I had ?

IIRC, I did not measure anything negative, but I can recheck next week when I'm back in the lab.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 15, 2020, 04:36:42 am
Hmm. Offhand, here's a... 2N2102, nice TO-39 can.  Setup:
9.76V supply
100 ohm series resistor to E
B = GND
C = open

E measures 7.54V (rising slowly as it warms up).
C measures -380mV, also rising slowly (i.e. towards zero) as it warms up.
C shorted, I measure -4uA.  Hey, not bad!

Presumably, leakage shorts out the photocurrent (or free charge current, whichever it is, I forget exactly) as it heats up, so the efficiency of this mode drops quickly, much as solar panels do.

With a 10k pullup from +9.76V to C, I measure 9.71V... or more precisely a drop of 38.8mV.  So, 3.88uA, consistent with the shorted measurement; seemingly less, but it's only a 5% resistor.

Collector current drops to -0.01mV (over 10k) when the emitter is open-circuited.  (Meter is fluctuating between -0.02mV and 0.00 when shorted.  This is the Hi-Z range, no loading on the circuit.  Not that it would matter out of 10k.)

With a 1M pullup, it still measures +/- 0.01mV.  Dang, this must be a nice transistor.  (Brand name Central Semi, yay?)

With a 10M pullup and a 22nF bypass cap in parallel with the resistor (just in case there's rectification here?), it's reading 0.14mV, a whopping -- 14pA?  Fuck me, that's damn good for a BJT, especially this size?

And, with the transistor removed from circuit, it's 11mV drop.  So, plus or minus a lot of leakage through the breadboard, or the meter itself.  (Meter with just the 10M and no ground or supply connection reads -0.07mV.)

Gosh... I slide my be-socked foot across the wood floor and the measurement goes nuts... :-DD  (Meter is just a BM235.)

Whelp... I'm sure you'll have much more noticeable results with a big fat power transistor, especially a sloppy one like 2N3055 (depending on age of the specimen..), or at higher voltages (9V is a far cry from the 120V rating of the 2N2102).

Tim
Title: Re: Transistors - die pictures
Post by: jaromir on May 15, 2020, 09:55:40 am
Regarding the glow of reverse biased PN junction of transistors or zeners, you state here https://www.richis-lab.de/REF03.htm (https://www.richis-lab.de/REF03.htm)
Quote
Während die Z-Diode leitet arbeitet sie zumindest zum Teil im Lawinendurchbruch. Wie bei den Versuchen mit den 2N3055-Transistoren ist dabei im Bereich der Sperrschicht ein Leuchten zu erkennen. Rekombinieren Ladungsträger in einem Siliziumhalbleiter, so emittieren sie üblicherweise kein Licht im sichbaren Bereich. Bei einem Lawinendurchbruch erfolgen allerdings relativ unkontrollierte Ionisierungen im Kristallgitter, die unter anderem auch sichtbares Licht erzeugen.
My German is rather poor, so I used google translator
Quote
While the Zener diode is conducting, it works at least in part in the avalanche breakdown. As in the experiments with the 2N3055 transistors, a glow can be seen in the area of the junction. If charge carriers recombine in a silicon semiconductor, they usually do not emit light in the visible range. In the event of an avalanche breakdown, however, relatively uncontrolled ionizations occur in the crystal lattice, which among other things also generate visible light.

I'm not sure whether this was debated here, but indeed the principle behind the glow is a bit peculiar one. I found relevant part of a book "Handbook of Silicon Photonics" here
https://books.google.sk/books?id=6zjNBQAAQBAJ&pg=PA347&lpg=PA347#v=onepage&q&f=false (https://books.google.sk/books?id=6zjNBQAAQBAJ&pg=PA347&lpg=PA347#v=onepage&q&f=false)
In a case the link above becomes dead, attached is excerpt with relevant part.
Title: Re: Transistors - die pictures
Post by: David Hess on May 15, 2020, 10:37:52 am
What magnitude?  Ic should be at least ~nA to start with; I would guess uA is reasonable to expect here?

10s of microamps is feasible with small signal devices.  a 4N25 used as a photovoltaic source is 10 times more efficient.
Title: Re: Transistors - die pictures
Post by: Noopy on May 15, 2020, 09:46:49 pm
I'm not sure whether this was debated here, but indeed the principle behind the glow is a bit peculiar one. I found relevant part of a book "Handbook of Silicon Photonics" here
https://books.google.sk/books?id=6zjNBQAAQBAJ&pg=PA347&lpg=PA347#v=onepage&q&f=false (https://books.google.sk/books?id=6zjNBQAAQBAJ&pg=PA347&lpg=PA347#v=onepage&q&f=false)
In a case the link above becomes dead, attached is excerpt with relevant part.

Very interesting!  :-+

I´m not sure if I understood the text 100%:
With a STM they were able to put a light in a silicon wafer. But they needed an energy of at least 3,2V.
In my view that is no "normal recombination", is it?
My understanding is that higher energies (=>avalanche) are necessary to get a glowing pn-junction. Normal recombination (normal conducting diode) can only generate heat, no light.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 16, 2020, 12:04:50 am
Yes, something like that.  High voltages also generally throw around charge carriers, and this can be used to inject charge through insulating barriers.  Which are just semiconductors with higher band gap than the base material, hence non-conductive at room temperature, or even elevated temperature.  But given charges with sufficient energy (or high enough temperature, same thing), well, they'll merrily grab a conduction band state and pass through.

Hence EEPROM and Flash, which is programmed by dumping a relatively high voltage through the channel, spraying some charge into the floating gate.  (Though I happen to forget how and why it's also electrically erasable.)  I suppose presumably you could see an extremely small amount of light emitted from such a chip as it's being erased or written, though as we're talking very small transistors and microamperes at best, probably not much.

And then yeah, they talk about, what, nanocrystals I suppose?  The band structure, rather than being an effectively-continuous band in a bulk material, it takes on recognizable discrete levels (effectively as many allowed levels as there are atoms along a given axis, I think?), and evidently some of these levels happen to not only correspond to lower visible wavelengths (red) but emissive states as well.

There's also something about implanting dyes or phosphors or other semiconductors (as nanodots) in silicon, that act as direct bandgap recombination centers, so there's just some free charges in the silicon that happens to diffuses over to these sites and emit light.

IIRC, something like that is what gives us modern high efficiency green LEDs, which are InGaN, normally a blue substrate (and still sporting the 3.0V drop you'd expect from it) but made to emit green instead.  These LEDs are recognizable not only from their much brighter output, but a... very slightly cyan-ier rather than yellower/lime-greenier hue?  Made a board some years ago that had a mixture of both on it for status LEDs, wasn't the most consistent appearance... :D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on May 16, 2020, 10:00:06 pm
Today I can show you a very cheap TO3-transistor, a 3DD15D:

https://www.richis-lab.de/Bipolar05.htm (https://www.richis-lab.de/Bipolar05.htm)


(https://www.richis-lab.de/images/Transistoren/05x04.jpg)

As I said: cheap…
Anyway the datasheet seems to contain some truth: Ptot=50W, Rth=2°C/W


(https://www.richis-lab.de/images/Transistoren/05x09.jpg)
(https://www.richis-lab.de/images/Transistoren/05x08.jpg)

But I´m not sure how they built this transistor. There are more areas than I would have suspected (red and blue)…  :-//
Title: Re: Transistors - die pictures
Post by: Jay_Diddy_B on May 17, 2020, 12:44:14 am
Hi,

If you have access to a metal lathe, you need to build this:

(https://www.eevblog.com/forum/repair/warning-fake-mj16012-transistors-on-ebay/?action=dlattach;attach=261701;image)

(https://www.eevblog.com/forum/repair/warning-fake-mj16012-transistors-on-ebay/?action=dlattach;attach=261703;image)

It puts the T03 can on the axis of the lathe and you can turn the top off.

(https://www.eevblog.com/forum/repair/warning-fake-mj16012-transistors-on-ebay/?action=dlattach;attach=261678;image)

Regards,
Jay_Diddy_B
Title: Re: Transistors - die pictures
Post by: Noopy on May 17, 2020, 07:38:10 am
If you have access to a metal lathe, you need to build this:
...

A good idea!  :-+
Unfortunatelly I have no access to a metal workshop...
Title: Re: Transistors - die pictures
Post by: Wolfgang on May 17, 2020, 10:02:36 am
I have one ! I will try this out. :)
Title: Re: Transistors - die pictures
Post by: Noopy on May 17, 2020, 08:08:02 pm
Finally a diode is half a transistor?  ;D

Today I have an old BAV45 for you:

https://richis-lab.de/Diode01.htm (https://richis-lab.de/Diode01.htm)


Not extremely interesting:

(https://richis-lab.de/images/Dioden/01x04.jpg)

Title: Re: Transistors - die pictures
Post by: Noopy on May 23, 2020, 10:17:15 pm
Today I have the breakdown of a SS109 for you:

https://www.richis-lab.de/Bipolar01.htm (https://www.richis-lab.de/Bipolar01.htm)


(https://www.richis-lab.de/images/Transistoren/01x05.jpg)
(https://www.richis-lab.de/images/Transistoren/01x06.jpg)
(https://www.richis-lab.de/images/Transistoren/01x07.jpg)
(https://www.richis-lab.de/images/Transistoren/01x08.jpg)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: RoGeorge on May 24, 2020, 01:15:44 am
Wow!   :-+

Is that ring of light visible to the eye, or is it infra red visible only by the camera?
Title: Re: Transistors - die pictures
Post by: Noopy on May 24, 2020, 07:11:24 am
The light is visible to the naked eye. It's dim and small but you can see it. :)
Usually silicon pn-junctions don't emit visible light but in avalanche breakdown the electrons are lifted to some higher energy levels.
Title: Re: Transistors - die pictures
Post by: Noopy on May 31, 2020, 08:15:16 pm
Today I have a Siemens ASY25 for you, it´s an old small signal alloy transistor:

(https://www.richis-lab.de/images/transistoren/06x01.jpg)

(https://www.richis-lab.de/images/transistoren/06x05.jpg)

 :wtf:
I assume they use this orange slurry to transfer heat from the transistor to the housing.


(https://www.richis-lab.de/images/transistoren/06x06.jpg)

(https://www.richis-lab.de/images/transistoren/06x09.jpg)

Germanium, yeah!  ;D


More Pictures on my website:

https://www.richis-lab.de/Bipolar06.htm (https://www.richis-lab.de/Bipolar06.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: RoGeorge on May 31, 2020, 10:50:08 pm
It's interesting that thermal paste is orange.  Is that orange because with time it developed rust inside?

When I was a kid I opened a few Romanian Ge transistors (AC180, AC181, EFT323, ASZ15, etc.) in order to turn them into photo-diodes (or photo-transistors).  Also we use to never throw away the broken high power transistors.  Those were usually filled with thermal paste, and we use to harvest the thermal paste and use it later on radiators.

Big or small, all the transistors I opened have had milky white thermal paste.

Since we are talking about die pics, recently bumped into a small power Ge that I opened during the 70's or 80's, in order to build an "Electronic Eye" from a book.  Back then the image sensor chips were not yet invented, so the so called "electronic eye" circuit was in fact just a light detector with a relay.   :)


[attachimg=1]
From left to right, the EBC of a PNP Ge transistor (EFT323 or AC180?).  E wire to junction EB was cut after opening the transistor


[attachimg=2]
View from the emitter side, E wire to the middle blob was cut, on the most left of the picture is the B wire


[attachimg=3]
View from the collector side, still shiny but heavily contaminated and with big residual reverse ICB, the DMM for the BC junction shows 1.3V when reverse polarized, and about 0.13V when direct polarized.

It has been staying in open air for decades, now rusty and with an almost dead BC junction, but it still is sensitive to light.  Stubborn!  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on June 01, 2020, 06:59:41 am
I didn't find any rust and the orange colour was very uniform. In my view the paste was orange from the start. Perhaps Siemens had a different thermal paste? But I agree with you, orange isn't normal. :)

Thank you for the pictures and the story behind!
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 01, 2020, 03:42:18 pm
I would assume it's condensation, polymerization or decomposition.  Perhaps it used to be an oil or resin.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on June 01, 2020, 08:42:19 pm
Today I proudly present a BUX22:

(https://richis-lab.de/images/transistoren/07x01.jpg)

(https://richis-lab.de/images/transistoren/07x03.jpg)

But  :wtf:  is it a fake?

(https://richis-lab.de/images/transistoren/07x04.jpg)

No, it´s an old BUX22!  :wtf: :wtf: :wtf:
Why should anyone put a new cap on an old BUX22?
Perhaps ST did some requalification and sold old parts as new?

(https://richis-lab.de/images/transistoren/07x06.jpg)

300V breakdown voltage
50A peak current
8A base current
 8)

But really interesting is this one:

(https://richis-lab.de/images/transistoren/07x17.jpg)

The BUX22 has some defects at which the glowing of avalanche breakdown occurs first.
The defects are big enough to identify that the glowing occurs next to the defect not exactly at the defect itself. That´s important for interpreting the glowing in the LTZ1000, discussed here:

https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg3086013/#msg3086013 (https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg3086013/#msg3086013)


Whole story and much more pictures here:

https://richis-lab.de/Bipolar07.htm (https://richis-lab.de/Bipolar07.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on June 01, 2020, 08:52:54 pm
@Wolfgang: I guess these pictures are also useful for your work.

(https://richis-lab.de/images/transistoren/07x11k.jpg)

 :-+ ;)
Title: Re: Transistors - die pictures
Post by: graybeard on June 03, 2020, 07:13:10 pm
Great photos!

Undesired recombination at the Si SiO2 interface will produce IR. That IR emission is used to find trouble spots.

Standard recombination in GaxAl1-xAs produces quite a bit of light since the dominant mechanism is optical emission.  The color typically ranges from IR to red depending on the composition.

Light emission due to avalanche  breakdown in GaAs is typically green.
Title: Re: Transistors - die pictures
Post by: Noopy on June 03, 2020, 07:28:45 pm
Thanks!  :-+

SiC glows blue. Looks really nice!  8)
Unfortunately I have no pictures of SiC-semiconductors...
Title: Re: Transistors - die pictures
Post by: Noopy on June 09, 2020, 03:43:32 am

Hi all!


Let´s take a look at a newer BUX22!

(https://richis-lab.de/images/Transistoren/08x01.jpg)

(https://richis-lab.de/images/Transistoren/08x03.jpg)

Well that´s a big heatspreader! It was necessary because the base plate of the package is thinner than the old generation (https://richis-lab.de/Bipolar07.htm (https://richis-lab.de/Bipolar07.htm)).


(https://richis-lab.de/images/Transistoren/08x04.jpg)

You can already see the thickness of the metal layer.
The BUX22 makes use of a perforated emitter. The die has a MESA-structure.


(https://richis-lab.de/images/Transistoren/08x06.jpg)

(https://richis-lab.de/images/Transistoren/08x09.jpg)

And of course second breakdown.  ;D


More pictures here:

https://richis-lab.de/Bipolar08.htm (https://richis-lab.de/Bipolar08.htm)

 :popcorn:

Title: Re: Transistors - die pictures
Post by: exe on June 09, 2020, 02:43:24 pm
I wonder why using two dies? As I see, both dies are in parallel without any balansing resistors. They must be very well matched, and, from the secondary breakdown pic, it looks like they are.

I also noticed a few red spots outside where they shouldn't be. I wonder what's that. Like, the one on the right die near the bottom pad.
Title: Re: Transistors - die pictures
Post by: Noopy on June 09, 2020, 02:49:24 pm
I wonder why using two dies? As I see, both dies are in parallel without any balansing resistors. They must be very well matched, and, from the secondary breakdown pic, it looks like they are.

Two smaller dies result in a better production yield than one big die.
And with two smaller dies you can use the same die but one for a smaller transistor.  :-+


I also noticed a few red spots outside where they shouldn't be. I wonder what's that. Like, the one on the right die near the bottom pad.

These are high iso pictures. There are some noise pixels…  ;D
Title: Re: Transistors - die pictures
Post by: Wolfgang on June 09, 2020, 03:53:05 pm
I wonder why using two dies? As I see, both dies are in parallel without any balansing resistors. They must be very well matched, and, from the secondary breakdown pic, it looks like they are.

I also noticed a few red spots outside where they shouldn't be. I wonder what's that. Like, the one on the right die near the bottom pad.

If a high power die is getting too large, temperature in the center is getting too high compared to the boundary due to limited heat conductance.
Not a problem for a 2N3055, but real for a BUX22.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 09, 2020, 04:57:48 pm
Not reeeeally... I've seen single MOSFET and IGBT dies bigger than the inside area of a TO-3.  More likely it was contemporary yields.

Don't know what the largest BJT die is, these days; might not even be one as large, just because there's so little demand for them.

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on June 09, 2020, 05:23:28 pm
Not reeeeally... I've seen single MOSFET and IGBT dies bigger than the inside area of a TO-3.  More likely it was contemporary yields.

Don't know what the largest BJT die is, these days; might not even be one as large, just because there's so little demand for them.

Tim

Same problem with MOSFETs. IXYS uses graded threshold voltages to tackle this problem (high threshold in the center) for their linear MOSFETSs.
All others - same story, with hotspotting in linear mode. See NASA, Spirito Effect.
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 09, 2020, 05:36:59 pm
I wonder why using two dies? As I see, both dies are in parallel without any balansing resistors. They must be very well matched, and, from the secondary breakdown pic, it looks like they are.

I also noticed a few red spots outside where they shouldn't be. I wonder what's that. Like, the one on the right die near the bottom pad.

We could drill out the remaining pin hole, and get a cheap matched pair transistor? :)
Title: Re: Transistors - die pictures
Post by: Noopy on June 09, 2020, 05:40:46 pm

We could drill out the remaining pin hole, and get a cheap matched pair transistor? :)


A very good idea!
I think that´s the ideal input stage for a small earphone amp!  ;D ;D ;D
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 09, 2020, 05:58:59 pm
Not reeeeally... I've seen single MOSFET and IGBT dies bigger than the inside area of a TO-3.  More likely it was contemporary yields.

Don't know what the largest BJT die is, these days; might not even be one as large, just because there's so little demand for them.

Tim

Same problem with MOSFETs. IXYS uses graded threshold voltages to tackle this problem (high threshold in the center) for their linear MOSFETSs.
All others - same story, with hotspotting in linear mode. See NASA, Spirito Effect.

The "reeeeally" being, most transistors that size are made for switching, so may have awful SOAs.  The power dissipation is there, no contest, just doing it at voltage is harder.

That said, many newer MOSFETs, and even some IGBTs, are specified with DC SOA.  However they've approached it -- graded threshold, tempco hackery, ballasting*, whatever -- it's done the trick.

*Probably not that, because source/emitter degeneration would severely eat into the saturated performance.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on June 11, 2020, 11:56:40 am
(https://www.richis-lab.de/images/Transistoren/07x13.jpg)

Did you know these small emitter contacts are called "wide-emitter narrow-contact"?
These structures make sure the current is evenly distributed. I assume that´s one reason why it was no bigger problem to connect the two dies in parallel.  :-+
Title: Re: Transistors - die pictures
Post by: Wolfgang on June 11, 2020, 12:05:31 pm
Not reeeeally... I've seen single MOSFET and IGBT dies bigger than the inside area of a TO-3.  More likely it was contemporary yields.

Don't know what the largest BJT die is, these days; might not even be one as large, just because there's so little demand for them.

Tim

Same problem with MOSFETs. IXYS uses graded threshold voltages to tackle this problem (high threshold in the center) for their linear MOSFETSs.
All others - same story, with hotspotting in linear mode. See NASA, Spirito Effect.

The "reeeeally" being, most transistors that size are made for switching, so may have awful SOAs.  The power dissipation is there, no contest, just doing it at voltage is harder.

That said, many newer MOSFETs, and even some IGBTs, are specified with DC SOA.  However they've approached it -- graded threshold, tempco hackery, ballasting*, whatever -- it's done the trick.

*Probably not that, because source/emitter degeneration would severely eat into the saturated performance.

Tim

Emitter ballasting is actually used, e.g., in high performance audio and, of course, RF power bipolar. More or less all "wide SOAR" stuff. Saturation voltage is of no concern there, and the drop along these resistors does not need to be large to equalize. Linear MOSFETS use the same trick at the source, among others, their RdsON is not as good as their switching cousins for the same reason.
Title: Re: Transistors - die pictures
Post by: Noopy on June 12, 2020, 08:21:02 pm

Today the last one of the BUX22-trilogy:


(https://richis-lab.de/images/transistoren/09x01.jpg)


(https://richis-lab.de/images/transistoren/09x03.jpg)

Yeah, pretty sure a fake.  :--
How did they cut the heatspreader?  :wtf:


(https://richis-lab.de/images/transistoren/09x05.jpg)

Someone has lost a solder ball.  :palm:


(https://richis-lab.de/images/transistoren/09x11.jpg)

Quite interesting MESA-structure!


(https://richis-lab.de/images/transistoren/09x07.jpg)

And here all three of them.


More pictures here:

https://richis-lab.de/Bipolar09.htm (https://richis-lab.de/Bipolar09.htm)


 :popcorn:
Title: Re: Transistors - die pictures
Post by: duak on June 12, 2020, 09:35:27 pm
I don't believe I've ever seen two dice paralled as in the BUX22 above.  Looking at a data sheet, I don't see anything calling that out.  I expect the dice are matched before packaging.  Any thoughts on the characteristics that make this possible?  I could see that emitter ballasting would help.

I was thinking of other applications for a dual power BJT that have reasonably matched dice with perhaps the bases and emitters brought out separately.  One thing would be simple current mirror with a current range up to a few amps, but the collectors would have to be electrically isolated from each other.
Title: Re: Transistors - die pictures
Post by: Wolfgang on June 12, 2020, 09:47:53 pm
It was common with bipolar RF power parts of the first generation (BLX15, ...)
Its obviously cheaper to have a bigger die when you really command the technology. If you dont,
yield goes substantially down with die size.
Title: Re: Transistors - die pictures
Post by: Noopy on June 13, 2020, 06:03:57 am
I don't believe I've ever seen two dice paralled as in the BUX22 above.  Looking at a data sheet, I don't see anything calling that out.  I expect the dice are matched before packaging.  Any thoughts on the characteristics that make this possible?  I could see that emitter ballasting would help.

I assume this "wide-emitter narrow-contact" technique makes it possible to connect the two dice.
I have heard that the BUX22 can often be seen connected in parallel without ballast resistors. Perhaps the BUX22 is a somewhat special bipolar transistor.  :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 14, 2020, 08:47:38 pm
Hi all!

I have started a 2N3055-page:

https://richis-lab.de/2N3055.htm (https://richis-lab.de/2N3055.htm)

Last one is a RCA 2N3055H which should contain a hometaxial transistor.

https://richis-lab.de/2N3055_05.htm (https://richis-lab.de/2N3055_05.htm)


(https://richis-lab.de/images/transistoren/11x01.jpg)

(https://richis-lab.de/images/transistoren/11x03.jpg)

(https://richis-lab.de/images/transistoren/11x12.jpg)

(https://richis-lab.de/images/transistoren/11x07.jpg)

The trench following the emitter electrode contains the base-emitter-junction as the pictures of the avalanche breakdown shows.


(https://richis-lab.de/images/transistoren/11x13.jpg)

But I´m not sure about the plateau following the trench. That has to be the emitter material. But why didn´t they design the base feed line shorter? There is no reason for more resistance in the base circuit. Perhaps the manufacturing process was the reason...  :-//

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on June 15, 2020, 08:37:13 pm
I took some more pictures of a RCA 2N3055:

https://richis-lab.de/2N3055_02.htm (https://richis-lab.de/2N3055_02.htm)

I´m pretty sure you can see the difference between the hometaxial and the epitaxial structure:


(https://richis-lab.de/images/transistoren/11x13.jpg)

2N3055H
Here you can see a trench and some "small hills". With a hometaxial construction you have to etch the emitter away to contact the base material.
The surface is uneven because it´s cut or grinded or whatever (mechanical).


(https://richis-lab.de/images/transistoren/12x05.jpg)

2N3055
The surface is very smooth. The reason behind this is the epitactical growth of silicon that gives a much cleaner surface.


  :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on June 17, 2020, 08:03:44 pm
Today I have a BD522 for you:

https://www.richis-lab.de/FET01.htm (https://www.richis-lab.de/FET01.htm)

(https://www.richis-lab.de/images/Transistoren/10x01.jpg)

(https://www.richis-lab.de/images/Transistoren/10x02.jpg)

(https://www.richis-lab.de/images/Transistoren/10x06.jpg)

(https://www.richis-lab.de/images/Transistoren/10x05.jpg)

It seems the metal layer is slightly shifted…

 :popcorn:
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 18, 2020, 02:45:03 am

The BD522  looks like it's got eyes, LOL!  :D
Title: Re: Transistors - die pictures
Post by: Noopy on June 18, 2020, 06:25:44 am
The BD522  looks like it's got eyes, LOL!  :D

You are right, didn´t see that!  ;D :-+
Title: Re: Transistors - die pictures
Post by: Noopy on June 19, 2020, 05:47:23 pm
Today a new ST TIP3055:

https://richis-lab.de/Bipolar10.htm (https://richis-lab.de/Bipolar10.htm)


(https://richis-lab.de/images/Transistoren/14x01.jpg)

(https://richis-lab.de/images/Transistoren/14x02.jpg)

Unfortunatelly the die didn´t survive in one piece but damage is not too bad.
I had only one try…


(https://richis-lab.de/images/Transistoren/14x03.jpg)

It uses a perforated emitter.  :-+


Thanks to exe for the part!

 :popcorn:
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 19, 2020, 05:54:13 pm

What's the thinking behind a perforated emitter?
Title: Re: Transistors - die pictures
Post by: Noopy on June 19, 2020, 06:01:49 pm
You connect the base over the whole die through perforations of the emitter. That gives you a better current Distribution and that leads to lower saturation voltage and second breakdown appears later.

Here you have more perforated emitter:
https://www.richis-lab.de/2SC2922.htm (https://www.richis-lab.de/2SC2922.htm)
https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)
Title: Re: Transistors - die pictures
Post by: Wolfgang on June 19, 2020, 08:30:30 pm
You connect the base over the whole die through perforations of the emitter. That gives you a better current Distribution and that leads to lower saturation voltage and second breakdown appears later.

Here you have more perforated emitter:
https://www.richis-lab.de/2SC2922.htm (https://www.richis-lab.de/2SC2922.htm)
https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)

Richie,

do you by accident have an 2N2857 at hand ?
I would be curious about this one.

Regards
   Wolfgang
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 19, 2020, 08:31:59 pm
You connect the base over the whole die through perforations of the emitter. That gives you a better current Distribution and that leads to lower saturation voltage and second breakdown appears later.

Here you have more perforated emitter:
https://www.richis-lab.de/2SC2922.htm (https://www.richis-lab.de/2SC2922.htm)
https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)

Thank you @Noopy, those articles taxed my German vocabulary to the limit, aber es ist etwas gut!
Title: Re: Transistors - die pictures
Post by: Noopy on June 19, 2020, 08:43:30 pm
do you by accident have an 2N2857 at hand ?
I would be curious about this one.

Hm... Have to take a look at my huge inbox. Got a lot of transistors the last few weeks.  ;D


Thank you @Noopy, those articles taxed my German vocabulary to the limit, aber es ist etwas gut!

 ;D Sorry for the german text but english would take me twice the time and I have so much more parts here.  :-/O A HF-Power-Transistor (the big one for GSM stations), a 18Bit-DAC, a 7,5A linear Regulator, a huge opamp and a looooot of smaller but also interesting parts.
I hope Google translator can help a bit and you can ask me here whatever you want.  :-+
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 19, 2020, 08:51:37 pm

Not a problem, es macht mir vergnugt to read your articles in German (aided by Google if I get stuck)

 :-+
Title: Re: Transistors - die pictures
Post by: Noopy on June 21, 2020, 08:20:20 pm
Well it´s not transistor but i switches transistors: the gate driver TC4429

https://www.richis-lab.de/TC4429.htm (https://www.richis-lab.de/TC4429.htm)

(https://www.richis-lab.de/images/TC4429/02.jpg)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on June 22, 2020, 07:42:38 pm
Today I have a TIP2955 for you. It´s the complementary transistor to the TIP3055.

https://richis-lab.de/Bipolar11.htm (https://richis-lab.de/Bipolar11.htm)


(https://richis-lab.de/images/transistoren/15x01.jpg)

(https://richis-lab.de/images/transistoren/15x02.jpg)

(https://richis-lab.de/images/transistoren/15x03.jpg)

It looks very similar to the TIP3055 and has exactly the same dimensions.


(https://richis-lab.de/images/transistoren/15x04.jpg)

The perforated emitter looks a bit different. You can see less circles in the "holes" than in the TIP3055. Unfortunatelly I don´t know how exactly the structures are built.  :-//

The TIP2955 came form exe.  :-+
Title: Re: Transistors - die pictures
Post by: exe on June 22, 2020, 07:59:20 pm
Thank you very much, this explains why some complementary pairs have very tight parameter matching (e.g., base capacitance). For some reason I expected NPN devices to be smaller for the same power rating. Either this is simply not true, or manufacturing process is well tuned.
Title: Re: Transistors - die pictures
Post by: Noopy on June 22, 2020, 08:06:57 pm
I have often seen mosfets where the p-type is bigger than the n-type. Last time in the TC4429.
I have often seen schematics where the pnp is doubled to achieve the same specifications than the npn.

But as we can see here it´s also possible to design the complementary transistors very similar.
Perhaps it´s a matter of priorities. Perhaps you can design complementary transistors equal but it´s easier to make the "p-type" bigger...  :-//

 :popcorn:
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 23, 2020, 10:20:35 am
NPN and PNP with similar build (i.e., those will be N and P substrate, then P/N, then N/P, epitaxy or diffusion) have similar properties.  PNP is only like 10-20% lower performance, I've forgotten exactly why now but clearly electrons and holes participate in the same way and mobility is a smaller factor in operation.

Want to say base diffusion is the only step in a BJT where mobility really matters, and the base can simply be made thinner if needed.  If that's the case, we might expect to find stronger Early effect; or, it's further compensated by collector doping profile, with subtle effects on breakdown voltage, Ccb(Vcb) and voltage drop, Idunno.

If a process is limited by shitty (usually lateral) PNP, large areas might be needed to compensate for that.

Complementary MOSFETs will always differ by about a factor of two, because mobility is a direct proportion in their performance.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on June 25, 2020, 12:09:00 pm
Today I can show you a TIP2955 built by ON-Semi:

https://richis-lab.de/Bipolar11.htm (https://richis-lab.de/Bipolar11.htm)


(https://richis-lab.de/images/transistoren/16x01.jpg)

(https://richis-lab.de/images/transistoren/16x02.jpg)

The die shows a classical construction. It is bigger (2,53mm*2,53mm) than the die in the ST-TIP2955 (2,42mm*2,15mm). I assume that´s because the classical design is less efficient than the perforated emitter design.


(https://richis-lab.de/images/transistoren/16x04.jpg)

A MESA-structure...  8)


The TIP2955 came form exe.


 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on June 25, 2020, 07:19:14 pm
Very interesting, thank you. My measurements showed that sy parts are a bit better than onsemi parts in terms of frequency response. Perhaps, due to smaller geometry. I think it's a trend, so I expect all ST bjts will be slightly smaller than onsemi.
Title: Re: Transistors - die pictures
Post by: Noopy on June 30, 2020, 08:57:46 pm

Today I have a SMART-Highside-MOSFET for you: VN02H


(https://richis-lab.de/images/Transistoren/13x01.jpg)

(https://richis-lab.de/images/Transistoren/13x02.jpg)

Everything on one die. That´s cool but gives you a clamping voltage of only -4V. There are special variants with -18V but that´s still not very much.


(https://richis-lab.de/images/Transistoren/13x18.jpg)
(picture taken from application note and modified)

Do you know why integrated SMART-Highside-Driver have low clamping voltages?
There is a parasitic bipolar transistor between the power transistor and the barrier around the logic part that is connected to the ground potential. You don´t need very much voltage to break the collector-emitter-line and kill the part.


(https://richis-lab.de/images/Transistoren/13x05.jpg)

The datasheet explains that the overcurrent detection is done with the temperature meassurement (this small satellite) but it seems that there are two small MOSFETs. Theses small MOSFETs can be used to sense the current through the VN02H...


(https://richis-lab.de/images/Transistoren/13x09.jpg)

And I have a dead one.  8)
It switched a short circuit.
The ground bondwire acted as a fuse. You can see a colored spot in the transistor area too.
Perhaps there was a overcurrent damage in the transistor and then the rest of the VN02H failed shorting the supply.  :-//
Perhaps there was somehow a transient overvoltage which killed the control part and then the power Transistor died.  :-//
We will never now for sure.


More Pictures here:
https://richis-lab.de/FET02.htm (https://richis-lab.de/FET02.htm)


 :popcorn:
Title: Re: Transistors - die pictures
Post by: David Hess on July 01, 2020, 02:01:25 am
Do you know why integrated SMART-Highside-Driver have low clamping voltages?
There is a parasitic bipolar transistor between the power transistor and the barrier around the logic part that is connected to the ground potential. You don´t need very much voltage to break the collector-emitter-line and kill the part.

I assume the dielectricly isolated process used for DMOS would be too expensive in both fabrication and area.

Quote
The datasheet explains that the overcurrent detection is done with the temperature meassurement (this small satellite) but it seems that there are two small MOSFETs. Theses small MOSFETs can be used to sense the current through the VN02H...

That is a very common technique for CMOS power devices and 4 pin power MOSFETs which allow monitoring the current.  A few cells of the power MOSFET have a separate drain connection brought out and the ratio of areas determines the fraction of the drain current which is detected.

It also works for bipolar devices.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 01, 2020, 02:17:18 am
Wow, surprised they waste so much die area on control logic!

Tim
Title: Re: Transistors - die pictures
Post by: David Hess on July 01, 2020, 02:35:12 am
An LM395 die shot would be interesting and I think I have seen it somewhere.  As I recall, it was very similar to the LM317 and might have been the same die with a different metalization.
Title: Re: Transistors - die pictures
Post by: Noopy on July 01, 2020, 03:12:22 am
Do you know why integrated SMART-Highside-Driver have low clamping voltages?
There is a parasitic bipolar transistor between the power transistor and the barrier around the logic part that is connected to the ground potential. You don´t need very much voltage to break the collector-emitter-line and kill the part.

I assume the dielectricly isolated process used for DMOS would be too expensive in both fabrication and area.

And with dielectric isolation you can´t build the more powerful vertical DMOS, can you?


The datasheet explains that the overcurrent detection is done with the temperature meassurement (this small satellite) but it seems that there are two small MOSFETs. Theses small MOSFETs can be used to sense the current through the VN02H...

That is a very common technique for CMOS power devices and 4 pin power MOSFETs which allow monitoring the current.  A few cells of the power MOSFET have a separate drain connection brought out and the ratio of areas determines the fraction of the drain current which is detected.

I know this kind of current measurement. It just surprised me that the datasheet by contrast explains a temperature based overcurrent detection.  :-//


An LM395 die shot would be interesting and I think I have seen it somewhere.  As I recall, it was very similar to the LM317 and might have been the same die with a different metalization.

I will put the LM395 on my to-do-list.  :-+
Title: Re: Transistors - die pictures
Post by: David Hess on July 02, 2020, 02:50:18 am
Do you know why integrated SMART-Highside-Driver have low clamping voltages?
There is a parasitic bipolar transistor between the power transistor and the barrier around the logic part that is connected to the ground potential. You don´t need very much voltage to break the collector-emitter-line and kill the part.

I assume the dielectricly isolated process used for DMOS would be too expensive in both fabrication and area.

And with dielectric isolation you can´t build the more powerful vertical DMOS, can you?

No, I don't think you can but the lateral power devices can still be very powerful.  Their disadvantage is that they take much more area.  On the other hand, they have much lower capacitance.
Title: Re: Transistors - die pictures
Post by: Noopy on July 02, 2020, 03:36:07 am
Well, you are right.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on July 05, 2020, 07:31:17 pm

Hi all!


Today I have a BD911 for you. It is quite simliar to the TIP3055 (https://richis-lab.de/Bipolar10.htm (https://richis-lab.de/Bipolar10.htm)). The collector-emitter-voltage and the hfe are a bit higher for the BD911.


(https://richis-lab.de/images/Transistoren/17x01.jpg)

(https://richis-lab.de/images/Transistoren/17x02.jpg)

The die is similar to the die in the TIP3055 but it´s smaller (4,66mm² vs. 5,25mm²) although it has the better specifications.
In my view ST was able to enhance the specificatons of the stackup. Probably the more close meshed perforation improves also the specifications.


(https://richis-lab.de/images/Transistoren/17x03.jpg)

I think they did some potential steering in the corners of the die.


(https://richis-lab.de/images/Transistoren/17x05.jpg)

The perforations are quite small compared to the TIP3055.


https://richis-lab.de/Bipolar12.htm (https://richis-lab.de/Bipolar12.htm)


Part was donated by exe.

 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on July 05, 2020, 08:16:49 pm
Very interesting, the die is smaller, however it looks like the "labyrinth" has more total length. I wonder which one has less parasitic capacitance.

Anyway, which one would be prefered for a linear power supply and why? :)
Title: Re: Transistors - die pictures
Post by: Noopy on July 05, 2020, 08:30:03 pm
My read is that the BD911 has less capacitance.
Less area => Less capacitance.

But perhaps the SOA of the BD911 is smaller. A smaller die is often heavier donated. But that´s only a guess…

Hard to decide which on is better for a linear power supply. BD911 has a higher voltage rating but perhaps TIP3055 has a bigger SOA...  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on July 06, 2020, 07:08:37 pm

Today I have an old TIP3055 built by TI:


(https://www.richis-lab.de/images/Transistoren/18x01.jpg)

(https://www.richis-lab.de/images/Transistoren/18x03.jpg)

The mold compound is very persistent...  :-/O


(https://www.richis-lab.de/images/Transistoren/18x04.jpg)

(https://www.richis-lab.de/images/Transistoren/18x05.jpg)

A classical mesa-design but OnSemi uses it still today for the TIP2955:
https://www.richis-lab.de/Bipolar11.htm (https://www.richis-lab.de/Bipolar11.htm)


You can find the TIP3055 overview here:
https://www.richis-lab.de/Bipolar10.htm (https://www.richis-lab.de/Bipolar10.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: David Hess on July 08, 2020, 12:39:17 am
A classical mesa-design but OnSemi uses it still today for the TIP2955:
https://www.richis-lab.de/Bipolar11.htm (https://www.richis-lab.de/Bipolar11.htm)

I was under the impression that the mesa process was long discontinued, except maybe for premium parts, because it is too expensive due to the time it takes to manufacturer.

Title: Re: Transistors - die pictures
Post by: Noopy on July 08, 2020, 02:31:10 am
A classical mesa-design but OnSemi uses it still today for the TIP2955:
https://www.richis-lab.de/Bipolar11.htm (https://www.richis-lab.de/Bipolar11.htm)

I was under the impression that the mesa process was long discontinued, except maybe for premium parts, because it is too expensive due to the time it takes to manufacturer.

 :-//
Perhaps it´s still cheaper than for example manufacturing a perforated emitter?
Perhaps there is an old production line working at a very reasonable price?
 :-//
Title: Re: Transistors - die pictures
Post by: Noopy on July 12, 2020, 08:03:56 pm
Today I have a very special transistor, the Programmable Unijunction Transistor 2N6027:

(https://www.richis-lab.de/images/Transistoren/21x01.jpg)

(https://www.richis-lab.de/images/Transistoren/21x02.jpg)

The die is very small: 440µm x 440µm.
However for 10µs a peak current of 5A is allowed.

These transistors are still in production.  :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on July 12, 2020, 09:19:36 pm
Wanted to ask before and censored myself, but I couldn't stand the itch any more:  What's the green and what's the yellow stuff?  What material is that?
Are those the real colors or are they colored by software?   :-[
Title: Re: Transistors - die pictures
Post by: Noopy on July 12, 2020, 09:31:33 pm
That are not the real colors an they are not colored by software.  ;D

With "normal light" you can only see the metal layer:

(https://www.richis-lab.de/images/howto/L_06a.jpg)

With light coming "from the camera" resonances are forming in the thin layers of the chip. Different thicknesses are creating different colors:

(https://www.richis-lab.de/images/howto/L_06.jpg)

Professional people use reflected-light microscopes. I use light coming from behind the die:

(https://www.richis-lab.de/images/howto/L_05.jpg)

It seems the lens is reflecting enough light to do the job.

 :popcorn:
Title: Re: Transistors - die pictures
Post by: magic on July 12, 2020, 09:57:18 pm
Multiple supposedly professional sources claim it's due to iridescence. Off the top of my head:

https://www.quora.com/Why-are-microprocessor-wafers-so-colorful (https://www.quora.com/Why-are-microprocessor-wafers-so-colorful)
http://www.designinganalogchips.com/ (http://www.designinganalogchips.com/)

It basically means you see the thickness of the surface layer of glass. This thickness varies, because glass accumulates on "finished" areas while new masks are applied and selectively etched to expose other areas to subsequent processing steps.
Title: Re: Transistors - die pictures
Post by: Noopy on July 12, 2020, 10:01:50 pm
I'm no optic expert but in principle that is what I said, resonances in thin layers, isn't it?
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 13, 2020, 02:18:07 am
There's kind of three things going on, actually:
- Doping
- Layers
- Patterns

Doped semiconductors actually reflect light differently.  I can't find a reference for it (go figure, searching for basic physics only turns up current high-level articles :palm: ) but it's something about the light's interaction with the carrier type and density, causing a phase or polarization shift, and therefore causing interference with the incident light.  There's an optical hall effect which might be what I'm thinking of, which is also affected by ambient magnetic fields as the name suggests.

Layers of semiconductor, oxide and etc. transmit light at different velocities, and are used in varying thicknesses, leading to simple interference colors.

Patterns, when periodic and finely etched (comparable to the wavelength of light), create diffraction gratings -- light is reflected from each wire in a bus, say, which when evenly spaced, causes interference at different angles -- a rainbow is reflected.  We don't see much of this on small devices (few features to reflect light) or large pitch devices (features are widely spaced), but it's why CDs, EPROMs and etc. are so colorful.

Note that interference depends on angle as well, as a glancing angle travels farther through the material.  So you generally get a play of colors over the surface of e.g. a microprocessor, but the exact rate (spectrum and angles) at which the colors are reflected varies by region.

A microprocessor is a good example, containing all of the above: well, probably not much visible semiconductor unless it's a quite old one, but periodic structures such as mask ROM, register files or caches, and buses, tend to show off all sorts of diffraction patterns, while "random logic" regions are more chaotic and have a noisy or speckled appearance.

Tim
Title: Re: Transistors - die pictures
Post by: magic on July 13, 2020, 07:01:10 am
Patters - true but not a thing at sufficient magnification, like in this thread.
Layers - as I said above, I think it's mostly about the layer of glass on the surface. Light penetration through actual silicon is very low (a few µm at best for red) and many of those structures are "relatively" deep.
Doping - not entirely sure. Anyone volunteers to treat a die to hydrofluoric acid to strip the glass and see if any color remains? Actually, people do such things (and also remove the metal layers which might obscure underlying silicon) and I think they end up needing to treat the die chemically to "stain" the doped areas. Look up "deprocessing" and "delayering".
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2020, 07:32:16 am
I definitely won´t work with hydrofloric. That´s some pretty nasty shit.  :scared:

It seems that deeper structures don´t show up in different colors. You can spot them only by the bumps they create at the surface.

(https://www.richis-lab.de/images/wafer/12.jpg)

Here the deep implant, the areas containing active elements and the lateral isolation have all the same color. That´s probably because of the low light penetration. No light no colors. All three structures are quite "deep".
Title: Re: Transistors - die pictures
Post by: magic on July 13, 2020, 09:14:52 am
The bumps which seem to be caused by collector buried layer are easy enough to explain - they are bumps on the surface of silicon itself, not differences in glass thickness, so the color is uniform.

But I'm not sure if the same is true about the bumps on isolation diffusions or what those bumps actually are :-//

Maybe doping does play some role.
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2020, 10:22:33 am
Hm...  :-//

The glass has to play a role. In the picture above the metal layer is missing but the vias are already etched. In the areas where the glass is missing you can see no color. Whereas around the vias you can see the color of the underlying layer.
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2020, 08:56:47 pm
I have taken some pictures of an old thyristor: ST103

https://www.richis-lab.de/Bipolar13.htm (https://www.richis-lab.de/Bipolar13.htm)


(https://www.richis-lab.de/images/transistoren/20x01.jpg)

(https://www.richis-lab.de/images/transistoren/20x05.jpg)

Looks pretty rude.


(https://www.richis-lab.de/images/transistoren/20x08.jpg)

A rough structure...


(https://www.richis-lab.de/images/transistoren/20x06.jpg)

Rough structures gives you a lot of leackage so they etched some traces to get smooth junction edges.

Title: Re: Transistors - die pictures
Post by: David Hess on July 14, 2020, 01:46:35 pm
Rough structures gives you a lot of leackage so they etched some traces to get smooth junction edges.

Like high voltage diodes, I thought the outer ring structure in thyristors was to prevent high voltage breakdown.
Title: Re: Transistors - die pictures
Post by: Noopy on July 14, 2020, 02:23:25 pm
Rough structures gives you a lot of leackage so they etched some traces to get smooth junction edges.

Like high voltage diodes, I thought the outer ring structure in thyristors was to prevent high voltage breakdown.

I think we are talking about the same mechanism:
The amount of leakage current is depending of the voltage.
More voltage, more leakage, triggering the thyristor...  :-BROKE
Title: Re: Transistors - die pictures
Post by: David Hess on July 14, 2020, 03:17:29 pm
Rough structures gives you a lot of leackage so they etched some traces to get smooth junction edges.

Like high voltage diodes, I thought the outer ring structure in thyristors was to prevent high voltage breakdown.

I think we are talking about the same mechanism:
The amount of leakage current is depending of the voltage.
More voltage, more leakage, triggering the thyristor...  :-BROKE

Time dependent false triggering in a thyristor is suppressed with metalization between the base and emitter of each transistor.  "Sensitive gate" SCRs are sensitive because they lack this.  An external resistor is less effective because of the distributed nature of the spreading resistance; the thyristor could be triggered in an area where there is too much resistance to the gate connection which is a very bad situation.

I was referring to the guard rings applied to semiconductor junctions including diodes and transistors which increase breakdown voltage.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 14, 2020, 03:30:40 pm
I don't think he was talking about rate?  Lacking a bit of nuance I think is all.

Namely: semiconductor breakdown is weird around the edges.  Guard rings are used to smooth out the electric field there, making breakdown less likely.  I forget exactly how these work; something about spaced P-N junctions, and maybe field plates too, that happens to do the job.

A fractured and contaminated edge can have all sorts of issues, including errant or intermittent conduction (due to stray charges, surface states and other arcana).  Passivated edges are better (keeps contamination out), but the materials can trap charges, and still transmit ambient electric fields (think random MOSFETs around the edges).

I would guess, for the technology of the day, they did the best with what they had: they probably found that etching the sidewalls, rather than leaving them open on the primary surface, simply gave better results.  The device might not be very tolerant of high voltage or rate stresses (avalanche and pulse operation?), but also maybe it was low enough voltage that it worked out okay.

Similarly, for a long time it used to be that silicon rectifiers were more fragile than some of the alternatives.  I guess that's sometimes still true today...  Avalanche-capable diodes were developed, and the huge energy capacity (relatively speaking) of a TVS diode, or a suitably rated MOSFET for that matter, can (probably?) only be possible this way, by preventing edge breakdown.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 14, 2020, 03:54:23 pm
Time dependent false triggering in a thyristor is suppressed with metalization between the base and emitter of each transistor.  "Sensitive gate" SCRs are sensitive because they lack this.  An external resistor is less effective because of the distributed nature of the spreading resistance; the thyristor could be triggered in an area where there is too much resistance to the gate connection which is a very bad situation.

I was referring to the guard rings applied to semiconductor junctions including diodes and transistors which increase breakdown voltage.

Didn't know that. Thanks for this information.

You talk about this ring?

(https://www.richis-lab.de/images/transistoren/20x06.jpg)

In my view that's for smooth edges of then pn junction where rough structures and contamination can lead to leakage...

(https://www.richis-lab.de/images/transistoren/20x09.jpg)

Guard rings are normally built with pn-structures and metal for all I know.


I agree with T3sl4co1l.
"Dirty edges" lead to all kind of negative characteristics.
In this thyristor I assume the biggest problem would be leakage current because worst case it can trigger the thyristor.
Title: Re: Transistors - die pictures
Post by: Noopy on July 15, 2020, 03:02:01 pm

I decapped a RF-Power-Transistor!  8)


(https://www.richis-lab.de/images/transistoren/19x01.jpg)

(https://www.richis-lab.de/images/transistoren/19x04.jpg)

In the package we find very long and thin transistors for best high frequency performance.
The capacitors are important for matching the Input and the output to the rest of the circuit.


(https://www.richis-lab.de/images/transistoren/19x05.jpg)

Nice!  8)


(https://www.richis-lab.de/images/transistoren/19x06.jpg)

(https://www.richis-lab.de/images/transistoren/19x07.jpg)

(https://www.richis-lab.de/images/transistoren/19x13.jpg)

There are some protection structures at both ends of the transistor die, probably zener or supressor.
The small transistors are too complex to identify the elements. Probably they used two metal layers.


(https://www.richis-lab.de/images/transistoren/19x16.jpg)

Hey they damaged the die!  :o But probably no bigger problem.


A lot more pictures on my website:

https://www.richis-lab.de/FET03.htm (https://www.richis-lab.de/FET03.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: RoGeorge on July 15, 2020, 05:01:23 pm
Wow, that's beautiful!    :-+

Datasheet says 2GHz https://www.nxp.com/docs/en/data-sheet/MRF18060A.pdf (https://www.nxp.com/docs/en/data-sheet/MRF18060A.pdf)
It's intriguing to see so many wire bonds inside of a 2GHz part, thinking here about parasitic inductance and stray capacitance.  ???
Title: Re: Transistors - die pictures
Post by: exe on July 15, 2020, 05:51:03 pm
Wow, rf beauty!

It's intriguing to see so many wire bonds inside of a 2GHz part, thinking here about parasitic inductance and stray capacitance.  ???

I thought the same. However, many wires in parallel will actually lower inductance.
Title: Re: Transistors - die pictures
Post by: Noopy on July 15, 2020, 08:12:25 pm
And most important is the impedance matching. To achieve this they even put capacitors in the package! 160pF gives you 0,5 \$\Omega\$ @2GHz but if the impedance matching is ok...  :-+
Title: Re: Transistors - die pictures
Post by: ocw on July 15, 2020, 10:25:34 pm
The MRF18060A pictures reminds me of what a SD2942 looks like "under the hood."  Attached are some pictures of it.

The SD2942 is a 500 watt dissipation 250 MHz MOSFET.  The pictures show one of the two matched MOSFET's in it which are used in a common source push-pull situation.  See:https://www.st.com/resource/en/datasheet/sd2942.pdf (https://www.st.com/resource/en/datasheet/sd2942.pdf)
Title: Re: Transistors - die pictures
Post by: David Hess on July 15, 2020, 11:35:53 pm
I would guess, for the technology of the day, they did the best with what they had: they probably found that etching the sidewalls, rather than leaving them open on the primary surface, simply gave better results.  The device might not be very tolerant of high voltage or rate stresses (avalanche and pulse operation?), but also maybe it was low enough voltage that it worked out okay.

The MESA structure apparently does the same thing as the guard rings which were used later.
Title: Re: Transistors - die pictures
Post by: ocw on July 16, 2020, 02:20:18 am
While significantly lower than the normal operating current and voltage, the attachment shows the excellent match in Id/Vds measurements on the two different halves on a SD2942.  The same measurements between two different MOSFET's shows a poor to no match.
Title: Re: Transistors - die pictures
Post by: magic on July 16, 2020, 05:20:11 am
I see the Vgs/Ids consistency being poor. If we adjust Vgs from 2.2V to 2.1V or 2V, the bottom three transistors have almost identical Vds/Ids behavior :box:
Title: Re: Transistors - die pictures
Post by: ocw on July 16, 2020, 01:18:11 pm
Sorry for the lack of an explanation of the Id/Vds graphs.  They showed six different curves at six different Vgs voltages for two matched MOSFET's located in the same physical package.  The first attachment of this message labels the A and B halves of the one matched MOSFET package.

The second attachment shows similar Id/Vds graphs for one half of two different SD2942 MOSFET packages.  The added 1 - 2 lines are between the two different MOSFET's at the same Vgs.  If they were matched they would be much closer together as they were on the first graph.  The match at the higher Vgs is what is important.

The curves in a matched MOSFET pair is typically close, like that shown.  While a perfect match is uncommon, much more significant mismatches between two different MOSFET packages with the same part number are not unusual.
Title: Re: Transistors - die pictures
Post by: magic on July 16, 2020, 02:47:09 pm
You are right, I didn't understand what was shown on the plot.

I was just nitpicking that you have only demonstrated a mismatch of Id vs Vgs rather than Id vs Vds :)
Frankly, you still are talking about Vgs mismtach.

That being said, we can actually see that one of the different FETs tends to have a sharper knee near zero than the other, regardless of Vgs and Id. So I guess that counts as a true mismatch of their Vds / Ids characteristics. I'm no expert on FETs so no idea what's causing this and if it's normal to see such differences correlated with threshold voltage of individual unit.
Title: Re: Transistors - die pictures
Post by: ocw on July 17, 2020, 09:21:24 pm
magic, you seem more comfortable in reviewing Id/Vgs curves.
The attachment shows the five curves from each of the two halves of one SD2942 almost overlapping as compared to the five curves from half of another SD2942 not coming close to the first ten.
Title: Re: Transistors - die pictures
Post by: magic on July 18, 2020, 04:55:01 am
This is kinda offtopic, but no, really not. It doesn't matter how you show it, it's just a philosophical question:

For a FET in the pentode region, is its Vds/Ids characteristic really anything other than just the drain impedance? If it takes different gate voltages to get the desired drain current on two parts, and then their drain impedance is about the same (high enough it's hardly even seen on those plots) is that really a difference in the Vds/Ids characteristic or just Vgs mismatch? That's all I have ever said, and as you see, I really don't  have that much to say :)

Also, I realize that drain impedance is probably not what you care about as long as it's "high enough", which probably isn't even that very high, as your schematic shows a 700Ω drain load.

If anything, it looks like the mismatched parts have different transconductance too, which might be relevant besides the different Id at given Vgs.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 18, 2020, 10:34:27 am
In the pentode region, the MOS equivalent of Early effect, is channel length modulation.  Drain conductance (y_oe) is usually very small indeed.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 23, 2020, 10:30:42 am
Today I have a MJL21193 for you (250V/16A/30A):

(https://www.richis-lab.de/images/transistoren/23x01.jpg)

The package has notches to increase the creepage distance.


(https://www.richis-lab.de/images/transistoren/23x02.jpg)

The die is quite big: 3,64mm x 3,54mm


(https://www.richis-lab.de/images/transistoren/23x03.jpg)

It´s a perforated Emitter MESA-Transistor just like the new BUX22 (https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm))


(https://www.richis-lab.de/images/transistoren/23x04.jpg)

(https://www.richis-lab.de/images/transistoren/23x05.jpg)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on July 23, 2020, 11:35:24 am
I wonder what is the biggest bjt (in terms of die area) ever produced?
Title: Re: Transistors - die pictures
Post by: Noopy on July 23, 2020, 11:47:39 am
I have a halfbridge brick sitting here (KD324510). The dies in there are much bigger. Could be something around factor three. I will take some pictures!  ;D
Title: Re: Transistors - die pictures
Post by: capt bullshot on July 23, 2020, 01:09:35 pm
It's not a BJT anyway, I've seen IGBT dice of 11mm * 16mm and larger. You'd find them in modules like this one:

(http://wunderkis.de/gallery/DSCN0148.orig.jpg)

Also have a few BJT modules, but their potting is pitch black, so one can't see the dice.
Title: Re: Transistors - die pictures
Post by: duak on July 23, 2020, 07:31:36 pm
I have some old BJT six-pack modules for a servo drive.  While looking for information on them I ran across the attached paper on the development of similar devices.  Page 2 shows the pre-potted assembly but without device ID or dimensions.  Assuming the overall dimensions are at least 30 mm x 50 mm the largest dice are maybe 10 mm x 10 mm.  If memory serves, these modules are attached with M4 or M5 screws so these dice could be even larger than that.

This fellow built a 3 phase linear amplifier using similar devices: http://wunderkis.de/pwramp3/index.html (http://wunderkis.de/pwramp3/index.html)

I toyed with the idea of making an electronic load with one of modules I have.  I've used one as a battery simulator to test a 50 A battery charger because it was easier than wiring a bunch of power MOSFETs or BJTs in parallel - I just needed a few zener diodes, resistors and wires with ring terminals.  The module was prone to high frequency oscillation when in the linear region at some currents so it seems that the basic devices are reasonably fast.  I think I read somewhere that these are triple diffused epitaxial to minimize switching losses.

These devices remind me of old IC engines with 5 litre cylinders and a 1000 RPM redline.  If memory serves, these run at about 2 kHz.

Title: Re: Transistors - die pictures
Post by: capt bullshot on July 23, 2020, 08:08:50 pm
This fellow built a 3 phase linear amplifier using similar devices: http://wunderkis.de/pwramp3/index.html (http://wunderkis.de/pwramp3/index.html)
That's me, by the way.


Quote
I toyed with the idea of making an electronic load with one of modules I have. 
I'd recommend against that:
- they "like" to oscillate
- their DC SOA isn't that great, they can die at way lower power levels than their maximum ratings if used in DC linear mode (I had this once or twice in my amplifier trying to use is as a DC current source). With AC output, even at as low frequencies as 50Hz, the SOA gets better.

Title: Re: Transistors - die pictures
Post by: duak on July 23, 2020, 10:11:43 pm
Ah, the capt himself.  Nice job on the driver and the write up is very clear - thank you!

Yes, the DC SOAs on the modules I have are not so good - a Pdmax of 200 W for a devices with a BVCEO of 500 V and an ICMAX of 100 A, clearly optimized for switching.  Their instability was a bit of a surprise as the servo drive they are from had 10 to 30 cm long wires and bus bars all over the place carrying drive signals and switched currents.  However, because it was a PWM, the devices weren't in the linear regime long enough to encounter trouble from oscillation.  After encountering the oscillation and reading the write up, it's back to the old plan.  Too bad, because the module would be simple to mount on a heat sink and wire up.
Title: Re: Transistors - die pictures
Post by: Wolfgang on July 23, 2020, 10:24:48 pm
Ah, the capt himself.  Nice job on the driver and the write up is very clear - thank you!

Yes, the DC SOAs on the modules I have are not so good - a Pdmax of 200 W for a devices with a BVCEO of 500 V and an ICMAX of 100 A, clearly optimized for switching.  Their instability was a bit of a surprise as the servo drive they are from had 10 to 30 cm long wires and bus bars all over the place carrying drive signals and switched currents.  However, because it was a PWM, the devices weren't in the linear regime long enough to encounter trouble from oscillation.  After encountering the oscillation and reading the write up, it's back to the old plan.  Too bad, because the module be simple to mount on a heat sink and wire up.

Try linear mosfets (IXYS). They are made for electronic loads.
Title: Re: Transistors - die pictures
Post by: David Hess on July 24, 2020, 04:06:10 am
Try linear mosfets (IXYS). They are made for electronic loads.

The problem is that unless you need maximum power in fewer packages, bipolar transistors just cost less for a given die area and power dissipation is proportional to die area.  So linear MOSFETs come with a double price premium which might even make lateral MOSFETs price competitive.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 24, 2020, 04:53:32 pm
Try linear mosfets (IXYS). They are made for electronic loads.

The problem is that unless you need maximum power in fewer packages, bipolar transistors just cost less for a given die area and power dissipation is proportional to die area.  So linear MOSFETs come with a double price premium which might even make lateral MOSFETs price competitive.

If you can find them...

But all of the above seem to be superseded by SuperJunction types, which regularly give DC SOA curves.  I've tested a few and found them to be accurate.  I'm not sure how they do it -- SJ have higher power density than ever, but they still manage not to runaway.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 28, 2020, 05:58:47 pm

Today I have a 2N2857 HF-Transistor for you.
It´s a quite interesting transistor manufactured by Central Semiconductor.


(https://www.richis-lab.de/images/Transistoren/24x01.jpg)

Central Semiconductor builds obsolete transistors. Originally the 2N2857 was built by Motorola.
This 2N2857 has a datecode 1738!  :-+


(https://www.richis-lab.de/images/Transistoren/24x04.jpg)

It has four pins. The housing is isolated.


(https://www.richis-lab.de/images/Transistoren/24x05.jpg)

To isolate the transistor it was package on the collector pin.  :-+ ;D
Thermal resistance is probably a bit higher...


(https://www.richis-lab.de/images/Transistoren/24x06.jpg)

(https://www.richis-lab.de/images/Transistoren/24x07.jpg)

The die is ~350µm*350µm.
There is a second transistor on the die probably to test the die. Interesting... Why didn´t they do the testing with the 2N2857 transistor itself?  :-//


And it glows:

(https://www.richis-lab.de/images/Transistoren/24x10.jpg)

1mA

(https://www.richis-lab.de/images/Transistoren/24x11.jpg)

5mA

 8)

Breakdown voltage is quite low (around -6V) because of high doping for high switching frequency.


More pictures here::

https://www.richis-lab.de/Bipolar16.htm (https://www.richis-lab.de/Bipolar16.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on July 28, 2020, 06:13:42 pm
Please excuse my ignorance, where is the second bjt located? Is it two big pads on the left on the close up shot?
Title: Re: Transistors - die pictures
Post by: Noopy on July 28, 2020, 06:17:14 pm
Please excuse my ignorance, where is the second bjt located? Is it two big pads on the left on the close up shot?

Yes it is. The two bigger pads are base and emitter and the smaller at the bottom corner is the collector.
Looking very carefully you can spot the corners of the emitter area around the emitter pad.
Title: Re: Transistors - die pictures
Post by: RoGeorge on July 28, 2020, 06:26:44 pm
I wouldn't expect it to be that smol!   ;D
Title: Re: Transistors - die pictures
Post by: David Hess on July 28, 2020, 06:56:28 pm
There is a second transistor on the die probably to test the die. Interesting... Why didn´t they do the testing with the 2N2857 transistor itself?  :-//

Could the tests be destructive like base-emitter breakdown voltage?
Title: Re: Transistors - die pictures
Post by: Noopy on July 28, 2020, 07:08:17 pm
There is a second transistor on the die probably to test the die. Interesting... Why didn´t they do the testing with the 2N2857 transistor itself?  :-//

Could the tests be destructive like base-emitter breakdown voltage?

Never heard of such testing but that would explain the second transistor...
Title: Re: Transistors - die pictures
Post by: exe on July 28, 2020, 07:16:00 pm
How do they pick and place such small dies? Or even cut them...

Those metal can packages... I have an urge to buy just for the sake of owning it.

PS I have Russian МП-42 (MP-42) somewhere, an old germanium transistor. I wanted to put it into use, but may be I should crack it open and see what's inside :). Can't find it atm, must be hiding from me....
Title: Re: Transistors - die pictures
Post by: Noopy on July 28, 2020, 07:21:00 pm
How do they pick and place such small dies? Or even cut them...

Those metal can packages... I have an urge to buy just for the sake of owning it.

PS I have Russian МП-42 (MP-42) somewhere, an old germanium transistor. I wanted to put it into use, but may be I should crack it open and see what's inside :). Can't find it atm, must be hiding from me....

And look at these small bond wires you have to place them accurate on the bondpad.
The handling must be pretty tricky.
Fascinating engineering!

The MP-42 is afraid...  ;D
Title: Re: Transistors - die pictures
Post by: David Hess on July 29, 2020, 02:50:03 am
There is a second transistor on the die probably to test the die. Interesting... Why didn´t they do the testing with the 2N2857 transistor itself?  :-//

Could the tests be destructive like base-emitter breakdown voltage?

Never heard of such testing but that would explain the second transistor...

It occurred to me because RF transistors often have a rated base-emitter breakdown voltage of only 3 volts instead of the more common 5 volts.
Title: Re: Transistors - die pictures
Post by: Zoli on July 29, 2020, 04:28:48 am
How do they pick and place such small dies? Or even cut them...

Those metal can packages... I have an urge to buy just for the sake of owning it.

PS I have Russian МП-42 (MP-42) somewhere, an old germanium transistor. I wanted to put it into use, but may be I should crack it open and see what's inside :). Can't find it atm, must be hiding from me....
Back in my times(30+years ago) I've opened quite a few from the MP38-42/P401-3 series; first, they are all Ge transistors; second, all of the structures are visible with the naked eye(die connection:1.00X0.01 mm Al or similar flat); third , don't blame my memory if there's something totally diferent inside; I just try to remember best of my impressions.
Title: Re: Transistors - die pictures
Post by: Noopy on July 29, 2020, 06:02:07 am
Back in my times(30+years ago) I've opened quite a few from the MP38-42/P401-3 series; first, they are all Ge transistors; second, all of the structures are visible with the naked eye(die connection:1.00X0.01 mm Al or similar flat); third , don't blame my memory if there's something totally diferent inside; I just try to remember best of my impressions.

Like this one?
https://www.richis-lab.de/Bipolar06.htm (https://www.richis-lab.de/Bipolar06.htm)
That's more mechanical engineering than electrical engineering.  ;D


Regarding the test-transistor:
Perhaps it was easier to test a transistor with all three terminals on the surface instead of the other transistor with it's collector on the back of the die...

Title: Re: Transistors - die pictures
Post by: magic on July 29, 2020, 06:40:38 am
These two transistors have the same collector ;)
Title: Re: Transistors - die pictures
Post by: Noopy on July 29, 2020, 06:48:27 am
These two transistors have the same collector ;)

That's right... It would have been enough to integrate a second collector pad instead of a whole transistor...  :-//
Title: Re: Transistors - die pictures
Post by: exe on July 29, 2020, 08:53:22 am
My friends, look what I found: P503, MP-16B, MP14-A and 2T803A (the big can) . The first one seems to be one of the first germanium bjt produced in the USSR. Accroding to http://www.155la3.ru/p501.htm, (http://www.155la3.ru/p501.htm,) they were developed in 1958-1959, and were in production for 5-6years. Rumors said they were discontinued due to extremely low yield of 1.8%.

It seems my P503 is not doing well or I'm measuring it wrong: [attach=1] . What should I do with it? Shall I keep it for children, donate somewhere, or open it? :)

PS This one was donated to me in late nighties by an ex-EE engineer among with many other old parts. It was sitting in a storage room until last year when I found it while traveling to my home town. I brought a few Soviet bjts back in hope to put them into use. Not sure how to use them. Build a distortion pedal for the guitar?

PPS I wanted to measure the diode drop, so I used a dmm that has test voltage of 3.2V. From my measurements, the forward voltage is 0.244, the reverse is 2.7, so it seems they broke down. According to datasheets, those germanium transistors are only rated up to 3V of reverse voltage.  Does it mean I killed them all?  :palm:

PPPS the year of production of P503 in question is 1963.
Title: Re: Transistors - die pictures
Post by: Noopy on July 29, 2020, 09:09:56 am
I quite sure you can't kill such a transistor with the diode tester. The current should be low enough.

Perhaps your transistor tester has a problem with the probably higher leakage currents?
Title: Re: Transistors - die pictures
Post by: Noopy on July 30, 2020, 07:17:47 pm
Today I have an older part for you, the 2N1561, a high-frequency-germanium-diffusion-alloy-mesa-transistor.  ;D


(https://www.richis-lab.de/images/Transistoren/25x01.jpg)

Nice packing.  8)


(https://www.richis-lab.de/images/Transistoren/25x02.jpg)

TO-107


(https://www.richis-lab.de/images/Transistoren/25x04.jpg)

Absorbent cotton?  :-//


(https://www.richis-lab.de/images/Transistoren/25x05.jpg)

The die is 0,57mm x 0,67mm.
It seems that the sawing of the dies was a bit of a problem. The edges are a little bit splinted.


(https://www.richis-lab.de/images/Transistoren/25x06.jpg)

I assume they had a p-doped substrate, diffused a n-doped base-layer on top of it and then placed a p-dopant and a n-dopant on top of it. After some baking yout get under the p-dopant an emitter and you can use the rest of the material to contact the emitter. The n-dopant gives you the base-contact.
Then some MESA etching and you get a nice clean (ok a bit shaky  ;D) base-collector-edge.


More pictures here:
https://www.richis-lab.de/Bipolar17.htm (https://www.richis-lab.de/Bipolar17.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on July 30, 2020, 08:52:09 pm
Quite some effort to produce a transistor. No wonders they used to be expensive.
Title: Re: Transistors - die pictures
Post by: Noopy on August 01, 2020, 07:30:22 pm
Today I have again a more simple germanium transistor for you:
ACY38 built by COSEM (France) which merged later with SESCO to SESCOSEM (=>Thomson=>SGS Thomson=>STMicroelectronic)


(https://www.richis-lab.de/images/Transistoren/26x01.jpg)

(https://www.richis-lab.de/images/Transistoren/26x02.jpg)

 :palm:
Paint stripper is good to remove this silicone oil based thermal paste.  :-+


(https://www.richis-lab.de/images/Transistoren/26x04.jpg)

Transistor is covered with some silicone stuff.


(https://www.richis-lab.de/images/Transistoren/26x05.jpg)

Unfortunatelly the wires were pulled of while removing the silicone.
But here you can see an interesting thing. The surface under the indium pill looks like it was machined. Actually that´s quite reasonable. A smooth surface gives you a better junction than a lot of roughness (different base thickness and varying doping).


(https://www.richis-lab.de/images/Transistoren/26x06.jpg)

Emitter...


More pictures here:

https://www.richis-lab.de/Bipolar18.htm (https://www.richis-lab.de/Bipolar18.htm)


 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on August 06, 2020, 09:26:53 pm
Well that´s a really old 2N3055:


(https://www.richis-lab.de/images/transistoren/27x01.jpg)

Who knows Solitron?  ;)


(https://www.richis-lab.de/images/transistoren/27x03.jpg)

Nice! You don´t need a datasheet to connect the transistor.  :-+ ;D


(https://www.richis-lab.de/images/transistoren/27x04.jpg)

(https://www.richis-lab.de/images/transistoren/27x06.jpg)

A classical transistor structure.
The solder is not applied evenly. That doesn´t look very promising.
The emitter connector seems to be dangerously long. It looks like it can short to the base...  :-//


(https://www.richis-lab.de/images/transistoren/27x07.jpg)

(https://www.richis-lab.de/images/transistoren/27x08.jpg)

(https://www.richis-lab.de/images/transistoren/27x09.jpg)

And breakdown light of course!  ;D => -16V / 0,5A


(https://www.richis-lab.de/images/transistoren/27x12.jpg)

It´s probably a hometaxial transistor. The surface (emitter) is partly etched down to connect the base.
You can see that the etched base area is smoother than the emitter area.


More pictures here:

https://www.richis-lab.de/2N3055_06.htm (https://www.richis-lab.de/2N3055_06.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 06, 2020, 11:06:10 pm
Hi Noopy,

nice, but what you see here is not a second breakdown, but the breakdown of the base emitter diode.
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2020, 03:07:25 am
Thank you Wolfgang!  :-+

Of course that´s not a second breakdown! I have corrected the text...
I had a long day...  :-//
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 07, 2020, 01:26:07 pm
Hi Noopy,

in fact it would be nice to see a second breakdown, but I guess you need a high-speed camera to get this on film.

Thanks for your good work !
 
  Wolfgang
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2020, 01:40:42 pm
I would need a high speed super-macro-camera with enough focal distance to protect the camera. That sounds expensive!  ;D

Thank you for the recognition!  :popcorn:
I still have some interesting parts in stock.  8)

Best regards,

Richard
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 07, 2020, 01:45:37 pm
Also 2nd breakdown probably doesn't emit any visible light, so you'd need a high framerate IR camera at that!

Tim
Title: Re: Transistors - die pictures
Post by: magic on August 07, 2020, 01:48:25 pm
That being said, you could still try basic avalanche breakdown of the BC junction. Just need a resistor-limited HV generator.
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2020, 01:55:21 pm
Also 2nd breakdown probably doesn't emit any visible light, so you'd need a high framerate IR camera at that!

Tim

I had in mind a second breakdown with high power. Getting that on a film would be pretty impressive even without IR sensitivity.  8)


That being said, you could still try basic avalanche breakdown of the BC junction. Just need a resistor-limited HV generator.

I once tried a breakdown of the BC junction of a transistor with low voltage rating (can´t remember which one). But I wasn´t able to see any light.
Perhaps that´s because most of the BC junction is covered under "a lot" of silicon.  :-//

Unfortunatelly higher breakdown voltages generate more heat so the transistor dies very quickly...  :-\
Title: Re: Transistors - die pictures
Post by: magic on August 07, 2020, 02:02:35 pm
Did you verify that there was current flow?
I tried measuring breakdown voltage of some BC857 once and found it to be over 100V, which was the limit of my generator. Basically, I applied 100V and nothing happened whatsoever.

Perhaps that´s because most of the BC junction is covered under "a lot" of silicon.  :-//
That's possible, although usually the edges of the junction reach the surface.
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2020, 02:13:30 pm
Yes I tracked the current. I finally found one that broke down <80V. I think it was a small HF Transistor.

Perhaps I should try it again...  :-/O :D
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2020, 08:24:39 pm
With "Perhaps I should try it again..." I wanted to say "I have to do that instantly!"  ;D

I took the 2N2857 with a maximum collector-base-voltage of 30V:

https://www.richis-lab.de/Bipolar16.htm (https://www.richis-lab.de/Bipolar16.htm)


Beginning at 57V(!) the current through the collector-base-junction reaches 10µA.



(https://www.richis-lab.de/images/Transistoren/24x12a.jpg)

=> 50µA
You can see a small glow in the upper right corner of the base rectangle.


(https://www.richis-lab.de/images/Transistoren/24x12b.jpg)

=> 100µA
The lower right corner starts to glow a little.


(https://www.richis-lab.de/images/Transistoren/24x12c.jpg)

=> 250µA
Now we see the corners!  :-+


(https://www.richis-lab.de/images/Transistoren/24x12d.jpg)

=> 500µA
The left corners start to glow.


(https://www.richis-lab.de/images/Transistoren/24x12e.jpg)

=> 1mA
The electrical field is highest in the corners of the rectangle and so the corners are illuminated first.


(https://www.richis-lab.de/images/Transistoren/24x12f.jpg)

=> 2mA


(https://www.richis-lab.de/images/Transistoren/24x12g.jpg)

=> 3mA
Then the right edge is lightening up.


(https://www.richis-lab.de/images/Transistoren/24x12h.jpg)

=> 5mA / 75V
I can´t go any higher. Probably with more power loss (>375mW) the 2N2857 would die anyhow.
It seems the area under the emitter contact is dark. The emitter isn´t connected but perhaps/probably the emitter contact somehow affects the electrical field.  :-//


 :popcorn:
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 08, 2020, 12:11:46 am
The emitter most definitely affects things -- C-E has a lower breakdown than C-B, effectively the C-B leakage is multiplied by hFE so runs away at a lower voltage (Vceo vs. Vcbo).  In the transition region between these two extremes, breakdown depends on e.g. B-E resistance; and breakdown can become exceptionally noisy, so much so that it can effectively switch "on" in a fraction of a nanosecond!

(I've observed avalanche switching in every transistor I've tested; the width of the region (in terms of what range of R_BE works reliably) varies, with most epitaxial parts being poor.  2N2369 is the classic, but 2N3904 also seems to do well.  Power transistors don't handle any more current before burning out, perhaps because avalanche only occurs in a small part of the whole junction, and isn't able to propagate over the full width.)

If the glow persists in Vceo or Vces mode, I wonder if it has any physical significance -- sufficient light output could perhaps cause the junction to ionize much sooner, and more broadly, than it would due to carrier diffusion alone!

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2020, 03:53:33 am
If the glow persists in Vceo or Vces mode, I wonder if it has any physical significance -- sufficient light output could perhaps cause the junction to ionize much sooner, and more broadly, than it would due to carrier diffusion alone!

I just did a short test of Vceo.
At ~45V over emitter-collector and ~10mA you can´t see any light.

I would have guessed to see at least some glowing...  :-//
Perhaps the breakdown ist more chaotic and distributed over the whole die... That would be a good explanation for  more noise... Just speculating...

Have to try Vces but no time left right now.
I assume the collector-base-junction will glow in that case but since a lot of current is flowing to the emitter I won´t be able to raise the current high enough to make the glowing visible before the transistor dies.
Title: Re: Transistors - die pictures
Post by: magic on August 08, 2020, 06:11:40 am
Another factor is beta: at 10mA collector current, only some 0.1mA may be flowing by means of breakdown and the rest because of the normal current gain of the transistor.
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2020, 02:17:17 pm
Another factor is beta: at 10mA collector current, only some 0.1mA may be flowing by means of breakdown and the rest because of the normal current gain of the transistor.

I quite agree with you!  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on August 12, 2020, 07:38:20 pm
(https://www.richis-lab.de/images/Transistoren/24x13.jpg)


Hm... Somehow I managed to kill the 2N2857...
Unfortunatelly I can´t say what went wrong. I was in a hurry. That´s never a good thing.   :-BROKE :-//
Title: Re: Transistors - die pictures
Post by: magic on August 12, 2020, 07:49:21 pm
Dunno, looks like you shorted out a PSU with that poor thing :P

Reminds me of that time I tried to weld a thermocouple with a laptop brick.
Title: Re: Transistors - die pictures
Post by: exe on August 12, 2020, 08:00:38 pm
May be it's only bound wires are broken. Is it possible to solder new wires to the die?
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 12, 2020, 08:43:47 pm
The die is discolored.  That's not just ash on top, that's an obliterated what-used-to-be-a-transistor.

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 12, 2020, 09:02:23 pm
(https://www.richis-lab.de/images/Transistoren/24x13.jpg)


Hm... Somehow I managed to kill the 2N2857...
Unfortunatelly I can´t say what went wrong. I was in a hurry. That´s never a good thing.   :-BROKE :-//

I guess the poor thing needed some limiting for current and power and did not get any :)
Seriously, these parts are not forgiving at all. When you look how they are mounted (on a pin header)
you can imagine that Rth is very large and heat capacitance is very small, i.e. they blow up in milliseconds.
Remedy: use a SMU and set the limits small enough. Fortunaterly, they are cheap.
Title: Re: Transistors - die pictures
Post by: Noopy on August 12, 2020, 09:21:58 pm
That´s not "medium" it´s more "well done".  ;D

@Wolfgang: SMU and cheap are two words that don´t match.  ;)
I still haven´t set up my HP-supply...  :-\
Title: Re: Transistors - die pictures
Post by: David Hess on August 12, 2020, 09:52:49 pm
Somewhere I have seen a table with bond wire fuse ratings for use in failure analysis.
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 12, 2020, 11:30:11 pm
That´s not "medium" it´s more "well done".  ;D

@Wolfgang: SMU and cheap are two words that don´t match.  ;)
I still haven´t set up my HP-supply...  :-\

Sorry I meant that the transistors are cheap. An SMU is not, and I know that after Keysight got all my money :)
Something affordable you could make is a current limiter circuit (I think there was a Jim Williams app note about an electronic fuse).
Thats not rocket science and will prevent a few kills.
Title: Re: Transistors - die pictures
Post by: Noopy on August 13, 2020, 04:16:42 am
 :-+ :)

Up to now I use a cheap bench supply but it has a current limiter of course.
I should have worked more concentrated. The fault is mine....
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 13, 2020, 09:50:08 am
Using a normal PSU with sensitive semiconductors is a problem even with a current limiter.
The problem is the energy stored in the output cap and the slow response of the limiter.
What you need is a limiter/electronic fuse that is fast and has no big electrolytic at the output side.
Title: Re: Transistors - die pictures
Post by: Noopy on August 13, 2020, 10:15:52 am
Yeah, I agree with that. A SMU would definitely be a nice piece of equipment. :)
Title: Re: Transistors - die pictures
Post by: RoGeorge on August 13, 2020, 12:39:07 pm
I proudly did once a demonstration about my latest tool purchase, a brand new Rigol DP832 power source, and how great it is, and how it can serve as a voltage source, or as a current source, upon wish.

And to prove my point, I set the current to 20mA and confidently hooked up a LED to the wires.   :-+

The LED flashed then instantly died with a violent pop sound, I jumped back, and my friend burst into laughter.  :-DD

Those 20mA were enough to charge a few thousands uF of output capacitors up to 32V, then all the energy rushed into the LED, limited only by the ESR and the wires.  In DP832, the output filtering capacitors are located at the end side, in direct contact with the output terminals.  ;D



Regarding the melted bonding wires, they are terminated in intriguingly round spheres of metal, and also there is a segment attached to each sphere, segment that looks like it was melted too but only at its surface, and somehow kept its initial cylindrical shape and its initial diameter, then the rest of the wire suddenly looks like brand new.

How is that possible?  :o
Title: Re: Transistors - die pictures
Post by: SilverSolder on August 13, 2020, 01:26:20 pm
I proudly did once a demonstration about my latest tool purchase, a brand new Rigol DP832 power source, and how great it is, and how it can serve as a voltage source, or as a current source, upon wish.

And to prove my point, I set the current to 20mA and confidently hooked up a LED to the wires.   :-+

The LED flashed then instantly died with a violent pop sound, I jumped back, and my friend burst into laughter.  :-DD

Those 20mA were enough to charge a few thousands uF of output capacitors up to 32V, then all the energy rushed into the LED, limited only by the ESR and the wires.  In DP832, the output filtering capacitors are located at the end side, in direct contact with the output terminals.  ;D

[...]


That's what happens when you use an instrument that is too new and inexperienced!  :D

(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1046336;image)
Title: Re: Transistors - die pictures
Post by: Mecanix on August 13, 2020, 03:23:29 pm
Those 20mA were enough to charge a few thousands uF of output capacitors up to 32V, then all the energy rushed into the LED, limited only by the ESR and the wires.  In DP832, the output filtering capacitors are located at the end side, in direct contact with the output terminals.  ;D

Interesting. Mine (DP832) ramps up beautifully, no inrush or spikes whatsoever on all 3CH, smooth as silk and stable. Recently had it calibrated also so add in that now impressive accuracy, its incredible now.
Title: Re: Transistors - die pictures
Post by: Wolfgang on August 13, 2020, 03:51:40 pm
Those 20mA were enough to charge a few thousands uF of output capacitors up to 32V, then all the energy rushed into the LED, limited only by the ESR and the wires.  In DP832, the output filtering capacitors are located at the end side, in direct contact with the output terminals.  ;D

Interesting. Mine (DP832) ramps up beautifully, no inrush or spikes whatsoever on all 3CH, smooth as silk and stable. Recently had it calibrated also so add in that now impressive accuracy, its incredible now.

I have a lot of DP832s, and they perform fine. Three things to take care:

- The startup spike only occurs when the load is *very* light.

- Its not an SMU, so accuracy is what is in the datasheet. Last digit has to taken with a larger grain of salt, as usual

- They do have an output cap, and the energy in this cap gets dumped into your load with no current limit being able to do anything against that.
So, if you set voltage to 30V, current to 10mA and then connect your LED, it could still be dead because of the cap discharge current.
Title: Re: Transistors - die pictures
Post by: RoGeorge on August 13, 2020, 06:47:39 pm
I apologize about telling the offtopic tale with the DP832.  I didn't want to hijack the topic.  Should have kept my mouth shut.  It was not the power source's fault, it was my mistake.  Just let it be.  Please let's get back on topic.

-----------------

Anybody knows more about the 2 spheres formed at the end of the melted bonded wires from the last transistor's pics?  Are they usually so round and alike looking?
Title: Re: Transistors - die pictures
Post by: capt bullshot on August 13, 2020, 09:44:06 pm
If you don't have an SMU, a bunch simple resistors should do the job.
Use the lab supply in voltage mode, roughly calculate the required resistance and put the resistor in series to the DUT. Measure the actural current with your multimeter and adjust the output voltage to set the desired current.
Disadvantage: for covering a larger range of currents, one has to switch resistors.
Your typical old-style curve tracer (e.g. Tek 576) does it this way. Pretty simple and effective. The modern ones have multiple digitally controlled SMUs to achieve the same results.
Title: Re: Transistors - die pictures
Post by: Noopy on August 13, 2020, 09:51:20 pm
Anybody knows more about the 2 spheres formed at the end of the melted bonded wires from the last transistor's pics?  Are they usually so round and alike looking?

Well the surface tension of the liquid metal forms a ball...


If you don't have an SMU, a bunch simple resistors should do the job.
Use the lab supply in voltage mode, roughly calculate the required resistance and put the resistor in series to the DUT. Measure the actural current with your multimeter and adjust the output voltage to set the desired current.
Disadvantage: for covering a larger range of currents, one has to switch resistors.
Your typical old-style curve tracer (e.g. Tek 576) does it this way. Pretty simple and effective. The modern ones have multiple digitally controlled SMUs to achieve the same results.

 :-+
Usually my bench supply is good enough for most applications.
I just have to keep calm while meassuring.
I was in a hurry that´s never good...  :--
Title: Re: Transistors - die pictures
Post by: Noopy on August 19, 2020, 06:53:19 pm
Today I have a MJL21193 for you (250V/16A/30A):

[...]

(https://www.richis-lab.de/images/transistoren/23x02.jpg)

The die is quite big: 3,64mm x 3,54mm


I was wrong with the die size!  :o
In fact the die is 5,48mm x 5,36mm! That´s quite big, 5,5 times the ST TIP3055!  8)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on August 19, 2020, 07:46:45 pm

Today I have a new 2N3055 for you, a Motorola 2N3055:

http://www.richis-lab.de/2N3055_07.htm (http://www.richis-lab.de/2N3055_07.htm)


(http://www.richis-lab.de/images/transistoren/29x01.jpg)

The characteristic old package with the characteristic low, more round cap.


(http://www.richis-lab.de/images/transistoren/29x03.jpg)

I don´t think that round low thing is a heatspreader. Perhaps they needed this small plate to manufacture the transistor.  :-//


(http://www.richis-lab.de/images/transistoren/29x04.jpg)

The design is "quite modern" and uses a mesa structure.


 8)


(http://www.richis-lab.de/images/transistoren/29x07a.jpg)

11V 10mA


(http://www.richis-lab.de/images/transistoren/29x07b.jpg)

20mA


(http://www.richis-lab.de/images/transistoren/29x07c.jpg)

30mA


(http://www.richis-lab.de/images/transistoren/29x07d.jpg)

40mA


(http://www.richis-lab.de/images/transistoren/29x07e.jpg)

50mA


(http://www.richis-lab.de/images/transistoren/29x07f.jpg)

100mA


(http://www.richis-lab.de/images/transistoren/29x07g.jpg)

200mA


(http://www.richis-lab.de/images/transistoren/29x07h.jpg)

300mA

 ;D
Title: Re: Transistors - die pictures
Post by: ocw on August 21, 2020, 10:52:48 pm
After prior pictures of a good SD2942W with more zoom https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3138636/#msg3138636 (https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3138636/#msg3138636) , attached is a picture of the same SD2942W with less zoom along with one damaged by lightning.
[attachimg=2]
Title: Re: Transistors - die pictures
Post by: Jay_Diddy_B on August 22, 2020, 02:53:28 am
Hi,

You need to find a big transistor like this one:

[attachimg=1]
(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1051410;image)

I have included a TO-3 transistor in the picture for scale.

The BJT is rated at 200A 700V.

I am not ready to open this one up. The silicon will probably be 33 or 38mm in diameter.

Regards,
Jay_Diddy_B
Title: Re: Transistors - die pictures
Post by: Noopy on August 22, 2020, 06:35:06 am
Well that's really a big one! :D
Title: Re: Transistors - die pictures
Post by: Noopy on September 05, 2020, 09:09:57 pm
Today I have a really old 2N3055:

(https://www.richis-lab.de/images/transistoren/30x01.jpg)

(https://www.richis-lab.de/images/transistoren/30x02.jpg)

(https://www.richis-lab.de/images/transistoren/30x05.jpg)

Here you can see the protective coating of the die and the higher emitter since it is a hometaxial transistor.


(https://www.richis-lab.de/images/transistoren/30x06.jpg)


Of course  I did some breakdown pictures. The fabrication process didn´t create very smooth structures. You can see that the breakdown light is quite non uniform even at high currents:


(https://www.richis-lab.de/images/transistoren/30x09a.jpg)

0,1A


(https://www.richis-lab.de/images/transistoren/30x09b.jpg)

0,2A


(https://www.richis-lab.de/images/transistoren/30x09c.jpg)

0,3A


(https://www.richis-lab.de/images/transistoren/30x09d.jpg)

0,4A


(https://www.richis-lab.de/images/transistoren/30x09e.jpg)

0,5A


(https://www.richis-lab.de/images/transistoren/30x09f.jpg)

0,6A


(https://www.richis-lab.de/images/transistoren/30x09g.jpg)

0,7A


(https://www.richis-lab.de/images/transistoren/30x09h.jpg)

0,8A


And there is a small structural flaw:


(https://www.richis-lab.de/images/transistoren/30x10a.jpg)

(https://www.richis-lab.de/images/transistoren/30x10.jpg)


https://www.richis-lab.de/2N3055_08.htm (https://www.richis-lab.de/2N3055_08.htm)


Title: Re: Transistors - die pictures
Post by: SilverSolder on September 06, 2020, 01:04:13 am

Interesting with that old 2N3055, it seems technology has moved on and we are making much "cleaner" devices nowadays?
Title: Re: Transistors - die pictures
Post by: Noopy on September 06, 2020, 07:03:34 am
That is for sure.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on September 06, 2020, 08:42:09 pm

Finally we can compare the hometaxial RCA 2N3055 with the epitaxial RCA 2N3055:


(https://www.richis-lab.de/images/transistoren/31x01.jpg)

(https://www.richis-lab.de/images/transistoren/31x03.jpg)

(https://www.richis-lab.de/images/transistoren/31x05.jpg)

(https://www.richis-lab.de/images/transistoren/31x06.jpg)

The metal layer has an interesting structure. It seems that RCA had to modify the layer to do some current steering. You can see that while driving the base-emitter-junction in breakdown:


(https://www.richis-lab.de/images/transistoren/31x10.jpg)

There are two very bright areas. There is no small bright point as we have seen with impurities. It´s more a line getting constantly brighter and dimmer. For sure that is a local higher current density.


(https://www.richis-lab.de/images/transistoren/31x07.jpg)

In the bottom left corner of the base contact RCA has integrated two holes in the emitter area to increase the resistance and reduce the current density.


(https://www.richis-lab.de/images/transistoren/31x08.jpg)

In the bottom right corner of the die RCA added even a small electrode connected to the base potential over the silicon.


https://www.richis-lab.de/2N3055_09.htm (https://www.richis-lab.de/2N3055_09.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on September 07, 2020, 04:28:50 am
Interesting with that old 2N3055, it seems technology has moved on and we are making much "cleaner" devices nowadays?

Early processing was incredibly crude by modern standards.  Today you could do better in your garage.
Title: Re: Transistors - die pictures
Post by: magic on September 07, 2020, 09:04:41 am
Maybe almost better ;)

https://hackaday.com/2010/05/13/transistor-fabrication-so-simple-a-child-can-do-it/
Title: Re: Transistors - die pictures
Post by: Noopy on September 07, 2020, 05:47:22 pm

I have taken pictures of a Motorola 2N3055I:


(https://www.richis-lab.de/images/transistoren/32x01.jpg)

(https://www.richis-lab.de/images/transistoren/32x02.jpg)

(https://www.richis-lab.de/images/transistoren/32x03.jpg)


It seems like the Motorola 2N3055I has a bigger die than the Motorola 2N3055 (https://www.richis-lab.de/2N3055_07.htm (https://www.richis-lab.de/2N3055_07.htm)). Perhaps the 2N3055I was a more robust version. Perhaps it´s a different generation of the 2N3055.  :-//
I didn´t find a 2N3055I in the Motorola data books, only a 2N3055A which seems to indicate parts with less ft).  :-//


https://www.richis-lab.de/2N3055_10.htm (https://www.richis-lab.de/2N3055_10.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on September 09, 2020, 09:10:47 pm
Hi all!

More power: Darlington-Halfbridge-Powermodul Powerex KD324510  8)


(https://www.richis-lab.de/images/Transistoren/33x01.jpg)

(https://www.richis-lab.de/images/Transistoren/33x04.jpg)

Ugly silicone potting...  :palm:


(https://www.richis-lab.de/images/Transistoren/33x06.jpg)

After a lot of cleaning...


(https://www.richis-lab.de/images/Transistoren/33x08.jpg)

(https://www.richis-lab.de/images/Transistoren/33x09.jpg)

The die is 16,0mm x 12,0mm. Two of them act as highside and two of them act as lowside.


(https://www.richis-lab.de/images/Transistoren/33x12.jpg)

Guard rings for the high voltage.


(https://www.richis-lab.de/images/Transistoren/33x13.jpg)

The diodes are 5,9mm x 3,9mm.
Constant current: 50A
Peak current: 500A


(https://www.richis-lab.de/images/Transistoren/33x14.jpg)

The diodes are also equipped with guard rings.


https://www.richis-lab.de/Bipolar19.htm (https://www.richis-lab.de/Bipolar19.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on September 10, 2020, 12:14:49 am
Hm, I wonder what the tradeoff is for metallized guard rings versus not.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on September 10, 2020, 05:51:48 am
Perhaps that´s necessary because of surface charge effects?  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on September 10, 2020, 08:15:31 pm
Today I have a 2N1613 for you:
https://www.richis-lab.de/Bipolar20.htm (https://www.richis-lab.de/Bipolar20.htm)

The 2N1613 is the first planar transistor worldwide and it´s still produced today.  :clap:


(https://www.richis-lab.de/images/transistoren/34x01.jpg)

This 2N1613 was built by Telefunken.


(https://www.richis-lab.de/images/transistoren/34x03.jpg)

(https://www.richis-lab.de/images/transistoren/34x02.jpg)

A small die (0,7mm x 0,7mm), nothing special...

 :-/O


Now you can find me on patreon: https://www.patreon.com/richis_lab (https://www.patreon.com/richis_lab)
Do you like my pictures?  ;)
Title: Re: Transistors - die pictures
Post by: RoGeorge on September 11, 2020, 07:06:13 am
Is all the yellow inside a gold plating?  It might justify outside, so the terminals won't oxidize, but why would gold plating be used inside the transistor's case?
Title: Re: Transistors - die pictures
Post by: Noopy on September 11, 2020, 07:22:13 am
I assume that´s all gold plating.
I further assume that they used gold platingt to assure a good bonding even if the package is stored open some time before attaching the die and closing the package.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on September 11, 2020, 04:29:28 pm
Might be a combination of bonding and contamination.  If it's bare metal, it's likely to spatter when spot-welded together.  Gold, copper, silver and alloys would be fine as a filler, spot-brazing it as it were.  Maybe just convenience as to putting it everywhere?

If the layer is very thin (as gold tends to be these days), it might not be enough to act as a filler; it might diffuse into the base metal, leaving little or no advantage for bonding purposes.  (It might simply be that a clean and smooth enough interface, with a well controlled welding process, doesn't spatter.  I'm sure this is relevant to later production; I have more than a few TO-39s that are full tin plated, so either would've been bonded like that, or bare and plated afterwards.  Hmm, and at that, most of them are smooth but a few Philips 2N4033 are starting to whisker..!)  If it was a heavier layer of gold, it could serve this way though.

It's interesting that only the base seems to be gold plated, which doesn't really go along great with either theory. :-DD

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on September 15, 2020, 03:22:11 am
I have forgotten to post the ITT 2N3055 here:

https://www.richis-lab.de/2N3055_11.htm (https://www.richis-lab.de/2N3055_11.htm)


(https://www.richis-lab.de/images/transistoren/35x01.jpg)

(https://www.richis-lab.de/images/transistoren/35x03.jpg)

(https://www.richis-lab.de/images/transistoren/35x04.jpg)

(https://www.richis-lab.de/images/transistoren/35x05.jpg)

(https://www.richis-lab.de/images/transistoren/35x06.jpg)

The hometaxial structure is easy to see.  :-+


(https://www.richis-lab.de/images/transistoren/35x08.jpg)

Of course it´s glowing!  8) And the ITT 2N3055 has a high BE breakdown voltage (-18V) as it is typically for hometaxial transistors.


(https://www.richis-lab.de/images/transistoren/35x09.jpg)

The current density is not perfectly uniform because of a lack of solder.

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on September 15, 2020, 06:43:34 am
Looks like the die of the ITT/2N3055 is not flat!   :o
Is that an optical illusion?  Is it even possible to make undulated chips?
Title: Re: Transistors - die pictures
Post by: Noopy on September 15, 2020, 06:51:31 am
That´s the hometaxial structure.

Where you want to contact the base you have to etch away the emitter diffusion. That gives you some "pretty high" steps on the die.

I have some eplaining pictures here:
http://www.richis-lab.de/2N3055_08.htm (http://www.richis-lab.de/2N3055_08.htm)
(taken from RCA transistor, thyristor & diode manual 1971)
Title: Re: Transistors - die pictures
Post by: Noopy on September 15, 2020, 07:31:54 pm

Recently I ordered a SiC-Cascode for burning it in my ofen...  >:D


(https://richis-lab.de/images/Transistoren/36x01.jpg)

A nice package for applications with higher voltages.
It also has a second source pin for more accurate gate control.


(https://richis-lab.de/images/Transistoren/36x10.jpg)

Manufacturing a SiC-J-FET is easier than a SiC-MOSFET. But for power electronics you usually want normaly off switches. Because of that UnitedSiC is building cascodes with a SiC-J-FET and a Si-MOSFET. With the Si-MOSFET we get the normal switching behaviour. Due to the SiC-J-FET the MOSFET has to carry the full current but only a small voltage.


(https://richis-lab.de/images/Transistoren/36x02.jpg)

In the package we see the two dies. The lower MOSFET-die is still in the epoxy.


(https://richis-lab.de/images/Transistoren/36x03.jpg)

The MOSFET is placed on a ceramic insulator.


(https://richis-lab.de/images/Transistoren/36x04.jpg)

The MOSFET is quite small for this big bondwires!
It was not easy to clean the die and we can´t see very much of the mosfet. It´s clearly a low voltage mosfet because there is no bigger gap between the metal layer and the edge of the die.


(https://richis-lab.de/images/Transistoren/36x06.jpg)

(https://richis-lab.de/images/Transistoren/36x11.jpg)

The SiC-FET-die is also not very spectacular, but...


(https://richis-lab.de/images/Transistoren/36x07.jpg)

(https://richis-lab.de/images/Transistoren/36x09.jpg)

It glows blue when you put current over the gate-drain-junction!  8) 1A in this picture.
The forward voltage is 3,5V which is enough for blue light.


https://richis-lab.de/FET05.htm (https://richis-lab.de/FET05.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on September 15, 2020, 08:27:02 pm
Cool!  GaN FET next? :D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on September 15, 2020, 08:31:20 pm
GaN is already sheduled!  :-+ ;D ...but it will take some time...
I also should take a closer look at a GaAs transistor...  :-/O
Title: Re: Transistors - die pictures
Post by: exe on September 16, 2020, 09:31:10 am
FERD diode please...
Title: Re: Transistors - die pictures
Post by: Noopy on September 16, 2020, 10:16:54 am
FERD diode please...

I can put it on my list.  :-+
(I still have some of your parts left...  ;))
Title: Re: Transistors - die pictures
Post by: daqq on September 16, 2020, 12:55:00 pm
Awesome photos!

I'd love to see what's inside a Behlke module :)
Title: Re: Transistors - die pictures
Post by: Noopy on September 16, 2020, 01:04:10 pm
Thanks!  :-+ :)

The Behlke module seems a bit too big for my ofen...  ::)
Title: Re: Transistors - die pictures
Post by: exe on September 16, 2020, 06:05:03 pm
I can put it on my list.  :-+

Please do!
Title: Re: Transistors - die pictures
Post by: Noopy on September 17, 2020, 08:55:45 pm
I just did a small update of the ST Microelectronics TIP3055. I added a new (better) die picture:

(https://www.richis-lab.de/images/Transistoren/14x02.jpg)

https://www.richis-lab.de/Bipolar10.htm (https://www.richis-lab.de/Bipolar10.htm)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on September 17, 2020, 10:17:50 pm
That looks downright good, like, a... MJE15000-something? I already forget what else has the perf emitter... [well, the BUX22 most similarly, but other than that too]

Does that one measure well, particularly in terms of switching speed?  (Have you tried, or got more to test?)

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on September 18, 2020, 03:16:40 am
I have noted which transistor is using a perforated emitter in my overview:
https://www.richis-lab.de/Transistoren.htm (https://www.richis-lab.de/Transistoren.htm)
Sorry, german...  ;)

That is the:
2SC2922 (Sanken) https://www.richis-lab.de/2SC2922.htm (https://www.richis-lab.de/2SC2922.htm)
(The 2SC2922 is especially interesting because the perforation is different. Sanken is splitting the emitter in small areas.)
BD911 (ST) https://www.richis-lab.de/Bipolar12.htm (https://www.richis-lab.de/Bipolar12.htm)
BUX22 new (ST) https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)
MJL21193 (ON) https://www.richis-lab.de/Bipolar15.htm (https://www.richis-lab.de/Bipolar15.htm)
TIP2955 (ST) https://www.richis-lab.de/Bipolar11.htm (https://www.richis-lab.de/Bipolar11.htm)
TIP3055 (ST) https://www.richis-lab.de/Bipolar10.htm (https://www.richis-lab.de/Bipolar10.htm)

I didn´t test the switching speed but the TIP3055 is one of a batch that exe gave to me to take pictures. I think he did some measurements.
exe?
Title: Re: Transistors - die pictures
Post by: exe on September 18, 2020, 09:26:59 am
I didn´t test the switching speed but the TIP3055 is one of a batch that exe gave to me to take pictures. I think he did some measurements.
exe?

I did some measurements, not sure how accurate they are. I also cannot find measurements for tip2955, showing tip3055 here. I was choosing a bjt for a power supply. I wanted the fastest one, so I bought ten or twenty different bjts and measured them I simply hooked base to a siggen (ad2), and measured collector or emitter current with 1 Ohm shunt (I forgot which configuration I used for these plots). My figure of merit was frequency at which the phase shift reaches 45 degrees.

Conditions: collector current Ic=2A, Vce ~=1V (plus 2V drop on 1ohm resistor, that's why in filename it says "3V", that's total psu output).

As one may see, the 45 phase shift happens at following frequencies:
tip3055: 47 kHz
2ta1943: ~18kHz
2sd882: 450 kHz (this transistor is much less beefy than prev two, hence the difference)

NB: Increasing Vce often helps, but I wanted to see performance when Vce is 1V and less.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on September 18, 2020, 02:33:59 pm
Hmm, do you know what h_fe was under that condition?

That should be the cutoff point, where it transitions from flat h_fe (from down to DC) to asymptotic (constant fT) behavior.  Which means fT = h_fe * Fc.

Tim
Title: Re: Transistors - die pictures
Post by: exe on September 18, 2020, 05:09:30 pm
Hmm, do you know what h_fe was under that condition?

That should be the cutoff point, where it transitions from flat h_fe (from down to DC) to asymptotic (constant fT) behavior.  Which means fT = h_fe * Fc.

Tim

Looking at plots, I kind of see it. The top plot is gain in db, and one can see it 20db/decade (very roughly). That is, when frequency increases for 10x, the gain falls by factor of 10. I attach the picture where it's more obvious. For some reason there is raise in gain at the end of slope. May be there is some sort of cross-talk. I also notice that the yellow line (base current) goes down at high frequencies. I don't know if it's a measurement artefact, or it's Miller capacitance, or something, but for some transistors it is quite high. May be I'm overdriving avg on ad2 as it can only supply 10mA. I also use jumper wires, so I expect measurements above 1MHz are inaccurate.


I can repeat measurement in a more controlled environment if one wants. I also ordered a few more transistors to see how they perform: D44H8, D45VH10G, D45H8G, D45H11G,  MJF45H11G, 2SD1060S-1E, KSE44H11, BD911, BD912,  D45H11FP and KSB772YS .
Title: Re: Transistors - die pictures
Post by: Noopy on October 06, 2020, 06:24:56 pm

I have taken a look into different *44H*-transistors.


D44H11

(https://www.richis-lab.de/images/Transistoren/37x01.jpg)

(https://www.richis-lab.de/images/Transistoren/37x02.jpg)

Decapping was a bit hot...  ::)


D44H8

(https://www.richis-lab.de/images/Transistoren/38x01.jpg)

(https://www.richis-lab.de/images/Transistoren/38x02.jpg)

It seems the D44H8 (specified for lower voltages) is the same as the D44H11. Perhaps ST does some binning and the higher quality is specified for higher voltages...


KSE44H11

(https://www.richis-lab.de/images/Transistoren/39x01.jpg)

(https://www.richis-lab.de/images/Transistoren/39x02.jpg)

On Semi (Fairchild) uses a different structure.
Don´t know why they integrated these holes in the metal layer...  :-//


(https://www.richis-lab.de/images/Transistoren/39x03.jpg)

In the KSE44H11 you can´t find a pn junction. I also wasn´t able to show some light in breakdown mode.
With a closer look at the emitter metal contact we find two steps. One is the contact to the emitter area. Perhaps the second step is the pn-junction. But why did ON hide it under the metal?   :-//


https://www.richis-lab.de/Bipolar21.htm (https://www.richis-lab.de/Bipolar21.htm)


The Transistors were donated by exe.  :-/O
Title: Re: Transistors - die pictures
Post by: exe on October 06, 2020, 09:07:24 pm
Niice, although I'm still not sure which one is better :).

Concerning the metal layer over the pn junction, Could it be to spread the heat?
Title: Re: Transistors - die pictures
Post by: Noopy on October 06, 2020, 09:13:54 pm
Concerning the metal layer over the pn junction, Could it be to spread the heat?

In my view that´s unlikely. The metal is only above the boundary of the pn-junction. Most of the junction is underneath the emitter.
Title: Re: Transistors - die pictures
Post by: Noopy on October 19, 2020, 08:05:50 pm

Do you know the 2N3553?


(https://www.richis-lab.de/images/transistoren/40x01.jpg)

RCA first sold this Power-HF-Transistor in 1966.
The 2N3553 combines a ft of 500MHz with a continous collector current of 0,33A (1A peak, 40V).


(https://www.richis-lab.de/images/transistoren/40x03.jpg)

Two bondwires for the emitter and two bondwires for the base. Probably that´s for low inductance and good current distribution.


(https://www.richis-lab.de/images/transistoren/40x04.jpg)

(https://www.richis-lab.de/images/transistoren/40x05.jpg)

The 2N3553 uses a multi emitter structure for low base resistance and fast switching.
RCA had this design patented: US3434019A


(https://www.richis-lab.de/images/transistoren/40x06e.jpg)

Lights on!  8)
Breakdown of the base-emitter-junction occurs at -6,5V (datasheet: -4V).
The light is quite uniform. In normal conduction mode an even current distribution is very important. Otherwise a high current in one transistor could cause thermal runaway.
But there is one transistor (center, left side) in which you can see only a line. There has to be an imperfection.  :-/O


More pictures here:
https://www.richis-lab.de/Bipolar22.htm (https://www.richis-lab.de/Bipolar22.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on October 23, 2020, 09:47:35 pm
(https://www.richis-lab.de/images/transistoren/41x01.jpg)

Westinghouse 156-043, that´s an old power ransistor!
(40V 15A)


(https://www.richis-lab.de/images/transistoren/41x03.jpg)

That´s an interesting potting. It seem´s to be clear with some brownish stuff added in the area of the die...  :-//


(https://www.richis-lab.de/images/transistoren/41x04.jpg)

(https://www.richis-lab.de/images/transistoren/41x05.jpg)

A hometaxial transistor.  :-+


(https://www.richis-lab.de/images/transistoren/41x06f.jpg)

Base-Emitter-Breakdown!  ;D (1,5A)
It seems that the structures are quite inhomogeneous. The right side of the die shows almost no light.


More pictures here:
https://www.richis-lab.de/Bipolar23.htm (https://www.richis-lab.de/Bipolar23.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on October 24, 2020, 09:56:27 am
That's another brand I've never heard of. Looking in up in wikipedia, it seems they were quite big back in the day, until dissolved in other companies.
Title: Re: Transistors - die pictures
Post by: Noopy on October 24, 2020, 10:52:44 am
Westinghouse is known for old big generators, all kind of old power distribution, nuclear reactors and much more.
But till this one I haven´t seen a Westinghouse transistor too.  8)
Title: Re: Transistors - die pictures
Post by: Noopy on October 28, 2020, 01:35:21 pm
Let´s look at a big darlington built in the "Gleichrichterwerk Stahnsdorf": SU510


(https://richis-lab.de/images/transistoren/42x01.jpg)

800V / 30A / 250W


(https://richis-lab.de/images/transistoren/42x03.jpg)

Without screws you can simply slide out the top cover.


(https://richis-lab.de/images/transistoren/42x07.jpg)

Under the black case there is a white silicone similar to "normal" silicone protecting the semiconductors.
On the bottom there is a thin black layer. I assume the black layer just had to hold the case during assembly and applying the white potting.
On top there is a brownish hard potting. Obviously this material protects the silicone since the top of the case is virtually open.


(https://richis-lab.de/images/transistoren/42x09.jpg)

Cutting the metal sheet contacts you can remove the brown part. The silicone potting had to be removed with patience. On thin layers silicone remover can help.


(https://richis-lab.de/images/transistoren/42x11.jpg)

In the package there are four Darlington-Dies and a large freewheeling diode. Two small diodes are connected in parallel to the base emitter junction of the driver transistor for faster switch off.


(https://richis-lab.de/images/transistoren/42x12.jpg)

The small diodes own only small structures at the edges because they don´t have to withstand high voltages.


(https://richis-lab.de/images/transistoren/42x13.jpg)

(https://richis-lab.de/images/transistoren/42x15.jpg)

The darlington transistor die is quite interesting. In the upper area there is the driver transistor. In the lower area there is the power transistor. Between these transistors they etched a trench. I wonder what exactly is the purpose of this trench. It somehow has to isolate the two transistors.
In the middle of the die you can see the resistor connected between base and emitter of the power transistor.


(https://richis-lab.de/images/transistoren/42x18.jpg)

The freewheeling diode has to withstand the full voltage and because of that has etched edges to reduce leakage current.


More pictures here:

https://richis-lab.de/Bipolar24.htm (https://richis-lab.de/Bipolar24.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 01, 2020, 06:02:30 pm

(https://www.richis-lab.de/images/Transistoren/43x01.jpg)

I took a closer look into a Westinghouse 1561-0403 (50V/15A). I wanted to see how similar it is to the 156-043 (40V/15A).


(https://www.richis-lab.de/images/transistoren/43x02.jpg)

The 1561-0403 also has this yellow-brown potting but here it is more homogenous.
And Westinghouse used some years after the 156-043 a smaller die although the 1561-0403 can withstand higher voltages. Interesting...


(https://www.richis-lab.de/images/Transistoren/43x05.jpg)

The base-emitter breakdown is also very inhomogenous (1A).


https://www.richis-lab.de/Bipolar25.htm (https://www.richis-lab.de/Bipolar25.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 06, 2020, 10:46:10 pm
(https://www.richis-lab.de/images/transistoren/44x01.jpg)

Have you ever heard of Greaves?  :-//


(https://www.richis-lab.de/images/transistoren/44x02.jpg)

We find a small modern die in the package.


(https://www.richis-lab.de/images/transistoren/44x04.jpg)

The transistor is shorted between collector and emitter.


(https://www.richis-lab.de/images/transistoren/44x06.jpg)

But hey, the base-emitter-junction is good enough for some light (1A)!  ;D


https://www.richis-lab.de/2N3055_12.htm (https://www.richis-lab.de/2N3055_12.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 17, 2020, 12:53:25 pm
Today I have a IGBT for you: IXYS IXGH48N60C3D1


(https://www.richis-lab.de/images/transistoren/45x01.jpg)

(https://www.richis-lab.de/images/transistoren/45x02.jpg)

Different packages but same internal construction / dies.


(https://www.richis-lab.de/images/transistoren/45x03.jpg)

On the left we see the IGBT. On the right we see the freewheeling diode.


(https://www.richis-lab.de/images/transistoren/45x04.jpg)

(https://www.richis-lab.de/images/transistoren/45x05.jpg)

The IGBT is 7,2mm x 6,1mm


(https://www.richis-lab.de/images/transistoren/45x07.jpg)

Potential steering to manage the high voltage.


(https://www.richis-lab.de/images/transistoren/45x08.jpg)

In the gap between the two metal areas you can spot the traces conducting the gate current under the emitter area.


(https://www.richis-lab.de/images/transistoren/45x10.jpg)

The freewheeling diode is 6,6mm x 4,2mm.


(https://www.richis-lab.de/images/transistoren/45x11.jpg)

Probably there is also potential steering but they have put some black stuff on this area.


https://www.richis-lab.de/Bipolar26.htm (https://www.richis-lab.de/Bipolar26.htm)


By the way I have done some sorting:
Here you can find the bipolar silicon transistors: https://www.richis-lab.de/Transistoren.htm (https://www.richis-lab.de/Transistoren.htm)
Here you can find the bipolar germanium transistors: https://www.richis-lab.de/Transistoren_Ge.htm (https://www.richis-lab.de/Transistoren_Ge.htm)
Here you can find the FETs: https://www.richis-lab.de/Transistoren_FET.htm (https://www.richis-lab.de/Transistoren_FET.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: exe on November 20, 2020, 12:29:52 pm
Wow, those igbt and diode are quite large.
Title: Re: Transistors - die pictures
Post by: Miyuki on November 20, 2020, 12:59:06 pm
Wow, those igbt and diode are quite large.
It must be huge when
IC25 TC = 25°C (Limited by Leads) 75 A

So bond wires are weaker than die itself  >:D
Title: Re: Transistors - die pictures
Post by: Noopy on November 20, 2020, 07:09:25 pm
Wow, those igbt and diode are quite large.
It must be huge when
IC25 TC = 25°C (Limited by Leads) 75 A

So bond wires are weaker than die itself  >:D

Oh yes, current needs silicon area!  :-+ 8)


Let´s take a look at an older transistor again:


(https://www.richis-lab.de/images/Transistoren/46x01.jpg)

Siemens AD148, a Ge-PNP-transistor: 26V, 3,5A, 0,45MHz


(https://www.richis-lab.de/images/Transistoren/46x02.jpg)

I assume this white powder absorbs humidity.


(https://www.richis-lab.de/images/Transistoren/46x04.jpg)

That´s an interesting colour...  :o ;D 8)
Siemens used one plate for base and emitter connection which is cut after production. We have seen that in the Siemens 2N3055 too: https://www.richis-lab.de/2N3055_01.htm (https://www.richis-lab.de/2N3055_01.htm)


(https://www.richis-lab.de/images/Transistoren/46x05.jpg)

(https://www.richis-lab.de/images/Transistoren/46x06.jpg)

Here you can see the ring electrode connecting the Ge-plate acting as base.
The whole transistor is placed on a socket.
On top of the base you can spot a edged pit with some plating. I assume that´s indium to form the emitter.
The emitter is connected with something like tin.


https://www.richis-lab.de/Bipolar27.htm (https://www.richis-lab.de/Bipolar27.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on November 20, 2020, 08:27:31 pm

Some of these pictures are quite beautiful and wouldn't look out of place at an art exhibition, LOL!  :D
Title: Re: Transistors - die pictures
Post by: Noopy on November 21, 2020, 06:08:29 am

Some of these pictures are quite beautiful and wouldn't look out of place at an art exhibition, LOL!  :D

Thanks!  8)
Till know I only have a calender: https://www.meinbildkalender.de/richis-lab (https://www.meinbildkalender.de/richis-lab)
Next "merchandise project" is a LTZ1000 coffee pot.  :D
Title: Re: Transistors - die pictures
Post by: floobydust on November 21, 2020, 07:32:32 am
Apparently tin whiskers are a problem with old germanium transistors, causing short circuits.
NASA failure analysis of vintage radio transistors OC170 and AF114: https://nepp.nasa.gov/whisker/anecdote/af114-transistor/2005-Brusse-tin-whiskers-AF114-transistors.pdf (https://nepp.nasa.gov/whisker/anecdote/af114-transistor/2005-Brusse-tin-whiskers-AF114-transistors.pdf)
Title: Re: Transistors - die pictures
Post by: Noopy on November 21, 2020, 08:27:02 am
Thanks for the hint!   :-+
I will take a closer look at the next germanium transistor. Would be nice to take pictures of some whiskers!  :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 25, 2020, 07:37:29 am
Today I have a Motorola 2N2081 for you:


(https://www.richis-lab.de/images/Transistoren/47x01.jpg)

(https://www.richis-lab.de/images/Transistoren/47x02.jpg)

Germanium-PNP-Powertransistor: 45V, 15A, 170W (@25°C), but a quite low ft of 5kHz...  ???


(https://www.richis-lab.de/images/transistoren/47x03.jpg)

The 2N2081 has an additional base contact in the middle of the die like the AU103 (https://www.richis-lab.de/Bipolar03.htm (https://www.richis-lab.de/Bipolar03.htm)).


(https://www.richis-lab.de/images/Transistoren/47x04.jpg)

Nice!  8)


Some more pictures here:

https://www.richis-lab.de/Bipolar28.htm (https://www.richis-lab.de/Bipolar28.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on November 25, 2020, 08:14:39 am
ft of 5kHz...

That's the slowest transistor I've seen! I see a plastic cover on collector (?) pin. Did it come in original packaging?
Title: Re: Transistors - die pictures
Post by: Noopy on November 25, 2020, 08:39:05 am
The small pin is for locating base and emitter and holding the transistor in place while tightening the nut.
The plastic cap ensures insulation to the heatsink. You put something like mica under the transistor but the pin needs some extra insulation.

The datasheet states min 5kHz. But nevertheless that´s quite low.
I noticed that in contrast the AU107, also a Ge-Powertransistor, has a quite high ft of 10MHz.
Perhaps the 2N2081 has a lower doping level reducing it´s speed. The datasheet states a quite high maximum die temperature of 110°C. For the AU107 you find 90°C. Perhaps that was the tradeoff.  :-//
Title: Re: Transistors - die pictures
Post by: Miyuki on November 25, 2020, 09:35:59 am
Why did they use a whole round crystal for transistors back then?
Is it some property of germanium that it can't be processed like silicon on bigger crystal and then cut to dies or just wasn't the technology to produce bigger crystal back then?
Title: Re: Transistors - die pictures
Post by: Noopy on November 25, 2020, 12:40:54 pm
Sorry, I´m no expert regarding the manufacturing of these old transistors.
Perhaps someone else knows more?

PS: First appearance of the 2N2018 was 1961 as far as I was able to trace it back.
Title: Re: Transistors - die pictures
Post by: RoGeorge on November 25, 2020, 03:25:04 pm
Why did they use a whole round crystal for transistors back then?
Is it some property of germanium that it can't be processed like silicon on bigger crystal and then cut to dies or just wasn't the technology to produce bigger crystal back then?

I'm not an expert either, but recently bumped into this documentary about the beginning of the semiconductors technology (this one is about Japan).  There are four parts, and the first one is especially about Ge transistors.
https://www.eevblog.com/forum/chat/fun-for-nerds/msg3297026/#msg3297026 (https://www.eevblog.com/forum/chat/fun-for-nerds/msg3297026/#msg3297026)

It will not explicitly answer your questions, but will let you make an idea about the zeitgeist of the electronic industry back then.
Title: Re: Transistors - die pictures
Post by: Miyuki on November 27, 2020, 11:58:22 am
It will not explicitly answer your questions, but will let you make an idea about the zeitgeist of the electronic industry back then.
It kinda explains it
They are Alloy transistor
So they are manufactured this way and size, not cut after manufacture
Interesting
Title: Re: Transistors - die pictures
Post by: Noopy on December 01, 2020, 07:46:50 pm
Next "merchandise project" is a LTZ1000 coffee pot.  :D

Done: https://www.redbubble.com/de/i/tasse/Referenzspannungsquelle-LTZ1000-von-Richis-Lab/63614214.9Q0AD (https://www.redbubble.com/de/i/tasse/Referenzspannungsquelle-LTZ1000-von-Richis-Lab/63614214.9Q0AD)  8)

The LTZ1000 clock looks quite interesting...  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on December 05, 2020, 10:41:59 pm
Today I have a Dual-J-FET for you, the DN1682:


(https://www.richis-lab.de/images/transistoren/49x01.jpg)

(https://www.richis-lab.de/images/transistoren/49x03.jpg)

It´s a Dual-J-FET witch matched transistors.


(https://www.richis-lab.de/images/transistoren/49x05.jpg)

It looks like they have cut the wafer in two steps. Often hat is done to reducing damage in the active area.


(https://www.richis-lab.de/images/transistoren/49x06.jpg)

A normal J-FET.
45 61 probably gives the die a unique number for matching the right parts.


More pictures here:
https://www.richis-lab.de/FET06.htm (https://www.richis-lab.de/FET06.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on December 06, 2020, 12:37:27 am
What's the purpose of the black goo around the dies?
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on December 06, 2020, 06:36:32 am
Weird, it's common-gate?

Wait... are those not actually the can?  And if they were, there wouldn't be any need for epoxy in the bottom.  Could those be... gate pins, coined flat for mounting the dies on?  Then the epoxy underfill is not so much to insulate (the hermetic seal should be fine) as to control vibration (so it's cemented down).

Hm, is the can floating, then?

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2020, 07:22:02 am
What's the purpose of the black goo around the dies?

It hold´s everything together. The black potting holds the pins in place.



Weird, it's common-gate?

Wait... are those not actually the can?  And if they were, there wouldn't be any need for epoxy in the bottom.  Could those be... gate pins, coined flat for mounting the dies on?  Then the epoxy underfill is not so much to insulate (the hermetic seal should be fine) as to control vibration (so it's cemented down).

Hm, is the can floating, then?

There are seven pins: 2x Gate-Drain-Source and one for the can so you can connect the can to whatever you want.
The flattened pins are the gate pins and are connected with a bondwire to the edge bondpad.

 :)
Title: Re: Transistors - die pictures
Post by: David Hess on December 06, 2020, 09:04:39 am
Weird, it's common-gate?

The connection to the gate is through the bottom of the die, so the die has to be insulated from the can.  Hybrid construction would take advantage of this to have only two wire bond connections on the top.
Title: Re: Transistors - die pictures
Post by: exe on December 06, 2020, 11:35:38 am
Today I have a Dual-J-FET for you, the DN1682

I'm surprised, I expected to see two weirdly-interleaved fets on a single die.
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2020, 11:40:00 am
I'm surprised, I expected to see two weirdly-interleaved fets on a single die.

That depends on what you want: Here the thermal coupling is worse but the capacitive and resistive coupling is much less than with one die.
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2020, 07:26:33 pm
(https://www.richis-lab.de/images/transistoren/48x01.jpg)

Do you know "Elektronska Industrija"? It was an Yugoslavian company and they also built a 2N3055.  :-+ ;D


(https://www.richis-lab.de/images/transistoren/48x02.jpg)

The transistor is remarkable similar to one generation of the the RCA 2N3055: https://www.richis-lab.de/2N3055_05.htm (https://www.richis-lab.de/2N3055_05.htm)


(https://www.richis-lab.de/images/transistoren/48x05.jpg)

There is some fiber glued to the die.  ???


(https://www.richis-lab.de/images/transistoren/48x09h.jpg)

An of course it´s glowing!  ;D
The breakdown voltage of the base-emitter-junction is quite high (-17V) because of the hometaxial construction.
Even with 1A there are some parts still dark due to the inhomogeneous structures.


More pictures here:
https://www.richis-lab.de/2N3055_13.htm (https://www.richis-lab.de/2N3055_13.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on December 06, 2020, 09:02:39 pm
Wow, I didn't know 3055 were so popular. So many companies were producing them...
Title: Re: Transistors - die pictures
Post by: serg-el on December 06, 2020, 09:39:17 pm
http://www.155la3.ru/kt818_19.htm (http://www.155la3.ru/kt818_19.htm)

Russian 3055
Title: Re: Transistors - die pictures
Post by: exe on December 06, 2020, 10:02:50 pm
btw, you reminded me that I also have a few bjts to open, and, coincidentally, I had a hacksaw at hand. How do you say I can make them glowing? :)
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2020, 04:29:11 am
The 2N3055 was the standard power transistor and was widely used. Back in the day there were a lot of semiconductor manufacturers...  :-/O

The base-emitter-junction is glowing in breakdown. Just connect a negative voltage to the base-emitter junction. HF-transistors often break down at 6V but I had an old Siemens hometaxial first breaking down at 70V (!). Normaly you see something around 10-20V. Be sure to limit the current and you have to cool the part or be fast: 20V*1A=20W  >:D
Title: Re: Transistors - die pictures
Post by: exe on December 07, 2020, 08:16:46 am
What is this white stuff on the crystal? How to remove it? I tried IPA, got some mild results. Will try a pcb cleaner in the evening.
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2020, 08:59:02 am
You can find many different protection coatings. Often it's a clear coating or nothing at all.
White stuff sounds like a silicone. That's quite hard to remove. Silicone cleaner can help but doesn't dissolve the stuff. In the end you have to peel it away. A plastic screw driver or something like that can help. You have to be careful not to damage the bondwires.
Title: Re: Transistors - die pictures
Post by: exe on December 07, 2020, 05:16:51 pm
Here is the transistor. Probably, the best picture I could make. The camera is slow to take pictures, so at 10A it burned out faster than "shutter" was able to take picture. This picture, is, afaik, at 5A. At 10A it blinked, and then I saw little sparks on the crystal. I think voltage was about 20V, and it became hot very fast. After that it rejected glowing, and only produced some sparks and smell. Poor bjt, RIP.
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2020, 09:12:48 pm
10A is a lot of current!  :o ;D
Sometimes I go up to 1,5A but with more current death comes fast...  >:D
Title: Re: Transistors - die pictures
Post by: exe on December 07, 2020, 09:20:49 pm
Sometimes I go up to 1,5A

Ouch :)
Title: Re: Transistors - die pictures
Post by: Wolfgang on December 08, 2020, 12:12:14 am
Noopy, what about pulsed measurements ?
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2020, 04:14:15 am
I do manually pulsing.  :-/O  ;D
Up to know that was sufficient.
Title: Re: Transistors - die pictures
Post by: Wolfgang on December 08, 2020, 10:59:39 am
Maybe, but you could use a lot more current if the duration is kept really low.
And its an interesting start problem for a computerized PSU / photography project.  >:D
Title: Re: Transistors - die pictures
Post by: exe on December 08, 2020, 11:19:14 am
BTW, my power supply can do pulses, I just thought I'll be quick-enough to do it manually. I was wrong. At 10A there was really little time to do the shot. I think it was about a second or less before brightness dropped, then sparks showed up.
Title: Re: Transistors - die pictures
Post by: magic on December 08, 2020, 12:04:45 pm
power dissipation = voltage drop · current

Just saying ;)
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2020, 12:27:19 pm
And its an interesting start problem for a computerized PSU / photography project.  >:D

Absolutely!  ;D :-+


BTW, my power supply can do pulses, I just thought I'll be quick-enough to do it manually. I was wrong. At 10A there was really little time to do the shot. I think it was about a second or less before brightness dropped, then sparks showed up.
power dissipation = voltage drop · current

200W  >:D ;D
Title: Re: Transistors - die pictures
Post by: Noopy on December 11, 2020, 02:31:38 pm
(https://www.richis-lab.de/images/Transistoren/50x01.jpg)

The SL113 is an old Silicon-HF-Powertransistor built by Halbleiterwerk Frankfurt Oder (60V, 400mA, 40MHz).


(https://www.richis-lab.de/images/Transistoren/50x04.jpg)

The "datecode" KB says august 1961 but there is a catalogue that states the development was finished in 1965.


(https://www.richis-lab.de/images/Transistoren/50x03.jpg)

Now that´s a strange wiring...


(https://www.richis-lab.de/images/Transistoren/50x05.jpg)

...and the bondwire is quite close to the bottom plate.


(https://www.richis-lab.de/images/Transistoren/50x07.jpg)

The die is attached on a round plate which is attached to the bottom plate of the package.


(https://www.richis-lab.de/images/Transistoren/50x09.jpg)

The die is 2,6mm x 1,6mm.
You can spot some minor damages.


(https://www.richis-lab.de/images/Transistoren/50x11.jpg)

The surface of the emitter (and only the emitter) is noticeable rough. I don´t know why...  :-//


(https://www.richis-lab.de/images/Transistoren/50x12a.jpg)

 ;D
10V 10mA


(https://www.richis-lab.de/images/Transistoren/50x12b.jpg)

20mA


(https://www.richis-lab.de/images/Transistoren/50x12c.jpg)

50mA
The current distribution is not very uniform.


(https://www.richis-lab.de/images/Transistoren/50x12d.jpg)

100mA


More pictures here:

https://www.richis-lab.de/Bipolar29.htm (https://www.richis-lab.de/Bipolar29.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on December 20, 2020, 08:33:36 pm
Hey, a glowing J-FET is missing!  ;D
Of course I had to change that:


(https://richis-lab.de/images/transistoren/49x09.jpg)

Breakdown voltage is 45V (D&S -> G). Current is 30mA.


(https://richis-lab.de/images/transistoren/49x10.jpg)

There is a light above and below of every gate electrode. One of the light strips of every gate electrode is mostly covered by the metal electrodes which are not perfectly aligned.


https://richis-lab.de/FET06.htm (https://richis-lab.de/FET06.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 24, 2020, 04:49:01 am
More power!  :box:


(https://www.richis-lab.de/images/Transistoren/52x01.jpg)

BUK446, a Power-MOSFET which can handle 800V (BUK446-800) or 1000V (BUK446-1000).
The B at the end makes it possible to conduct 1,5A (A gives you 1,7A). Peak current is 6A (6,8A).


(https://www.richis-lab.de/images/Transistoren/52x03.jpg)

(https://www.richis-lab.de/images/Transistoren/52x04.jpg)

The die is quite big for a TO220-package: 4,6mm x 4,5mm.


(https://www.richis-lab.de/images/Transistoren/52x05.jpg)

A lot of small MOSFETs as we know it.


(https://www.richis-lab.de/images/Transistoren/52x06.jpg)

They left the corners blank to reduce electrical stress. Sharp edges give you a high electrial field strenght which can lead to partial discharge and breakdown.
Around the active area there are potential steering rings for a smooth electrical field.  :-/O


https://www.richis-lab.de/FET07.htm (https://www.richis-lab.de/FET07.htm)

 :-+
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2020, 05:46:30 am
(https://www.richis-lab.de/images/Transistoren/53x01.jpg)

Tesla KU605


(https://www.richis-lab.de/images/Transistoren/53x02.jpg)

In the package glued on the lid is a white cylinder. The cylinder probably absorbs humidity.


(https://www.richis-lab.de/images/Transistoren/53x03.jpg)

(https://www.richis-lab.de/images/transistoren/53x04.jpg)

Still the die is potted with some red silicone.
Tesla used ribbon bonds. Interesting.


(https://www.richis-lab.de/images/transistoren/53x06.jpg)

(https://www.richis-lab.de/images/transistoren/53x07.jpg)

You can see the MESA-edge.
Tesla has put solder on the side of the die. I haven´t seen that in other power transistors.  :-//


(https://www.richis-lab.de/images/Transistoren/53x09.jpg)

The ribbon bond contact looks quite interesting.


(https://www.richis-lab.de/images/transistoren/53x10.jpg)

And of course it glows!  ;D
7,5V / 1A


https://www.richis-lab.de/Bipolar31.htm (https://www.richis-lab.de/Bipolar31.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: BravoV on December 26, 2020, 06:43:36 am
Great works and photos as usual, thank you.  :clap:  :-+

Still the die is potted with some red silicone.

What did you use or how did you clean the red silicone ? Using solvent ? Or else ?
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2020, 07:03:51 am
Thanks!  :)

You can peel away the red coating using tweezers, mostly in quite big parts. Thankfully it doesn't stick too hard and the ribbon bonds are quite robust.
The small remains didn't bother me.
Title: Re: Transistors - die pictures
Post by: SilverSolder on December 26, 2020, 04:08:04 pm

Those ribbons do look a lot more solid than the thin bond wires we normally see.  Wonder if they give any real advantages?
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2020, 04:29:44 pm
I assume back in these days every company had it's own special way of construction. Not everything was optimized to that extend it is today. These ribbon bonds have a pretty low resistance. But I'm afraid bonding such big metal work without damaging the die was not a easy task... :-/O
Title: Re: Transistors - die pictures
Post by: BravoV on December 26, 2020, 04:32:04 pm
And probably lower yield too compared to bond wires ?  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2020, 04:38:01 pm
Perhaps they wanted to keep the inductance low too.
OK, it´s a quite old and bulky part but after all it´s a switching transistor with a fg of at least 5MHz...
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2020, 11:01:32 pm

Let´s look inside a KU607 to compare it with the KU605:


(https://www.richis-lab.de/images/Transistoren/54x01.jpg)

210V vs. 200V
hFE and Ic are the same
70W vs. 50W
>9MHz vs. >5MHz
=> a little bit better than the KU605


(https://www.richis-lab.de/images/Transistoren/54x03.jpg)

Nothing special inside but there is no humidity absorber in this package.


(https://www.richis-lab.de/images/Transistoren/54x04.jpg)

Hey, the die area is the same as in the KU605 and also the structures look the same!
It seems Tesla has optimized the internal structures/doping...


https://www.richis-lab.de/Bipolar32.htm (https://www.richis-lab.de/Bipolar32.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 28, 2020, 04:36:04 am
(https://www.richis-lab.de/images/Transistoren/55x01.jpg)

KU608
Uce: 250V, 40V more than the KU607.


(https://www.richis-lab.de/images/Transistoren/55x02.jpg)

In the package I found an absorber like in the KU605 but with a different shape. In the KU607 there was no absorber. Strange...  :-//


(https://www.richis-lab.de/images/Transistoren/55x04.jpg)

Looks familiar...


(https://www.richis-lab.de/images/Transistoren/55x05.jpg)

But the die is slightly smaller (5,6mm x 5,7mm) than the die of the KU605 and the KU607 (5,8mm x 6,0mm).
It seems Tesla was able to optimize it´s transistor design...


(https://www.richis-lab.de/images/Transistoren/55x06.jpg)

C-E-short...  :-BROKE


https://www.richis-lab.de/Bipolar33.htm (https://www.richis-lab.de/Bipolar33.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 04, 2021, 05:42:38 am
(https://richis-lab.de/images/Transistoren/56x01.jpg)

Siliconix IRF640: 200V / 0,18 \$\Omega\$ / 18A / 72Ap


(https://richis-lab.de/images/transistoren/56x02.jpg)

(https://richis-lab.de/images/transistoren/56x03.jpg)

Quite a big die for a TO220-package: 5,8mm x 4,3mm  8)
Three metal lines are conducting the gate potential into the active area.


(https://richis-lab.de/images/transistoren/56x04.jpg)

A lot of tiny MOSFETs.  ;D


(https://richis-lab.de/images/transistoren/56x05.jpg)

In contrast to the high voltage MOSFET BUK446-1000B (https://richis-lab.de/FET07.htm (https://richis-lab.de/FET07.htm)) in the IRF640 the small transistors can also be found in the corners. Lower voltages => lower electrical field strength => less problems   ;D


https://richis-lab.de/FET08.htm (https://richis-lab.de/FET08.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on January 04, 2021, 11:03:49 am
Quite a big die for a TO220-package: 5,8mm x 4,3mm  8)

Power MOSFETs brought on development of TO-220 packages which could hold larger dies, and eventually larger TO-220 style packages.  Later TO-220 packages had a lead frame which barely fit within the encapsulation.  Current became so high that separate bond wires to the drain were replaced with a single strip of copper.

I always wanted more powerful bipolar transistors in those enhanced TO-220 packages but if they existed, I never saw them.

Quote
A lot of tiny MOSFETs.

Since the manufacturer is Siliconix, that makes it MOSPOWER!

https://archive.org/details/bitsavers_siliconixdixMOSPOWERApplications_38092918

An International Rectifier part would be a HEXFET with a hexagonal arrangement of cells.  Do they still make these?  I blew up enough of them.
Title: Re: Transistors - die pictures
Post by: Noopy on January 04, 2021, 12:21:38 pm
Power MOSFETs brought on development of TO-220 packages which could hold larger dies, and eventually larger TO-220 style packages.  Later TO-220 packages had a lead frame which barely fit within the encapsulation.

 :-+


Since the manufacturer is Siliconix, that makes it MOSPOWER!

https://archive.org/details/bitsavers_siliconixdixMOSPOWERApplications_38092918

Thanks for the link, that´s quite an interesting book!


An International Rectifier part would be a HEXFET with a hexagonal arrangement of cells.  Do they still make these?  I blew up enough of them.

I can´t answer that...  :-//
Title: Re: Transistors - die pictures
Post by: SK_Caterpilar_SK on January 04, 2021, 09:24:46 pm
Man I love this place its absolutely great to just gaze at lighting up transistors. But really? KD501 at 1A? Those things can to 10A continues safely ! you should really try them on a heatsink low voltage low disspation high current lets go light the entire room up. I thought the inside of the TO3s were dark cold places, indeed wrong lit by the current :D I like it.

If you ever come across a tesla germanium transistor such as 7NU74 73 or 6NU Take a look at those. I have milled one 6NU74 (because some sadistic murderer broke its legs off) and it turned out to be a metal capsule in which the semiconducotr was located. The metal "can" was split in 3 parts acting as electrodes I guess. Oh and It also had a rattly absorband inside. I rock a pair of 7NU74s in a AB amp and they are very interesting :)
Title: Re: Transistors - die pictures
Post by: jananetha on January 05, 2021, 08:31:11 am
can you share video link
Title: Re: Transistors - die pictures
Post by: Noopy on January 05, 2021, 08:46:53 am
But really? KD501 at 1A? Those things can to 10A continues safely !

But not over their base-emitter-junction and even less when "working" in breakdown!  :D


I thought the inside of the TO3s were dark cold places, indeed wrong lit by the current :D I like it.

There is quite some light in some semiconductors!   8) Sometimes even in normal operation! More coming soon... ;D


If you ever come across a tesla germanium transistor such as 7NU74 73 or 6NU Take a look at those. I have milled one 6NU74 (because some sadistic murderer broke its legs off) and it turned out to be a metal capsule in which the semiconducotr was located. The metal "can" was split in 3 parts acting as electrodes I guess. Oh and It also had a rattly absorband inside. I rock a pair of 7NU74s in a AB amp and they are very interesting :)

Sounds like this one:
https://richis-lab.de/Bipolar27.htm (https://richis-lab.de/Bipolar27.htm)



can you share video link

Which video link?  :-//

Title: Re: Transistors - die pictures
Post by: Noopy on January 05, 2021, 08:51:02 pm
(https://www.richis-lab.de/images/Transistoren/51x01.jpg)

TPIC2404: four 1A-Smart-Transistors with overvoltage protection, overcurrent protection, freewheeling diodes to an external potential, enable input and error output.


(https://www.richis-lab.de/images/transistoren/51x04.jpg)

The die is 3,9mm x 3,4mm and uses two metal layers.


(https://www.richis-lab.de/images/transistoren/51x09.jpg)

You can identify a lot of parts of the TPIC2404:
Green: Output transistor
Dark green: Output transistor driver
Dark blue: Freewheeling / Clamping diodes.
Red: Shunt for overcurrent protection
Blue: Overtemperature protection


(https://www.richis-lab.de/images/Transistoren/51x07.jpg)

1987


(https://www.richis-lab.de/images/Transistoren/51x11.jpg)

The parts of the output transistor are hard to identify because of the two metal layers.


(https://www.richis-lab.de/images/Transistoren/51x13.jpg)

Same with the driver transistor.


(https://www.richis-lab.de/images/transistoren/51x05.jpg)

Shunt-Current-Measurement


(https://www.richis-lab.de/images/Transistoren/51x06.jpg)

Temperature sensor


(https://www.richis-lab.de/images/transistoren/51x14.jpg)

Freewheeling / Clamping diode
It uses the two metal layers in parallel to get a low resistance in this small area.


(https://www.richis-lab.de/images/Transistoren/51x08.jpg)

(https://www.richis-lab.de/images/Transistoren/51x10.jpg)

The input protection has a transistor at the bondpad with base and emitter connected (red). Base-collector gives you a diode with a high breakdown voltages and protects the circuit against negative voltages.
In the collector area there is a MOSFET which can switch to ground (black). The green resistor is a pull-down for the gate. Via a small capacitor (yellow) a voltage surge activates the MOSFET and is shunted to ground.  :-+


https://www.richis-lab.de/Bipolar30.htm (https://www.richis-lab.de/Bipolar30.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 07, 2021, 07:46:55 pm
(https://www.richis-lab.de/images/Transistoren/57x01.jpg)

A little cursty.  :o It´s a Siemens AD133(-V), a Ge-PNP-Transistor: 32V, 15A, hfe 50-100 ("V" is the bin with the best hfe).


(https://www.richis-lab.de/images/Transistoren/57x02.jpg)

Pins with soldering eyelets  :-+
There is also a pin for the collector connection.  :-+


(https://www.richis-lab.de/images/transistoren/57x03.jpg)

There is a white drying agent in the package and a black potting on the transistor.


(https://www.richis-lab.de/images/transistoren/57x04.jpg)

IPA removes the black potting.


(https://www.richis-lab.de/images/transistoren/57x05.jpg)

As seen in the 2N3055 (https://www.richis-lab.de/2N3055_01.htm (https://www.richis-lab.de/2N3055_01.htm)) and the AD148 (https://www.richis-lab.de/Bipolar27.htm (https://www.richis-lab.de/Bipolar27.htm)) Siemens used a single metal plate which is soldered into the package and then has been fused.


(https://www.richis-lab.de/images/transistoren/57x06.jpg)

The die diameter is 4,4mm, only a little bit bigger than the diameter of the AD148 die (4,1mm).


https://www.richis-lab.de/Bipolar34.htm (https://www.richis-lab.de/Bipolar34.htm)

Title: Re: Transistors - die pictures
Post by: exe on January 07, 2021, 08:20:31 pm
How much did the transistors cost back in the day? Say, in 60-x, 70-x, and 80-x. I assume in 90-x they were affordable. I also heard PNP transistors were more expensive than NPN.
Title: Re: Transistors - die pictures
Post by: Noopy on January 07, 2021, 08:28:05 pm
How much did the transistors cost back in the day?

I don´t know that, would have to do some research.  :-//
But I´m sure one of the people reading this knows what you would have to pay back in the days.


I also heard PNP transistors were more expensive than NPN.

I´m pretty sure that´s wrong for Ge-transistors. PNP-transistors were easier to build. Not every manufacturer was even able to built npn power transistors.  :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 11, 2021, 06:20:32 pm
(https://www.richis-lab.de/images/Transistoren/58x01.jpg)

SMY51, a dual-pMOS built 1973 by Funkwerk Erfurt.


(https://www.richis-lab.de/images/Transistoren/58x02.jpg)

The die contains two zener to protect the gate.


(https://www.richis-lab.de/images/Transistoren/58x03.jpg)

On the die there is some gel potting.


(https://www.richis-lab.de/images/Transistoren/58x05.jpg)

You can see the comb-shaped drain and source. On top of drain and source there is the gate electrode. Under the transistors there are the z-diodes connecting the gates to the substrate.


https://www.richis-lab.de/FET09.htm (https://www.richis-lab.de/FET09.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 15, 2021, 08:25:08 pm
FERD diode please...

I have a FRED in stock.

But right now I can show you a IGBT with a "HEXFRED".


(https://www.richis-lab.de/images/Transistoren/59x01.jpg)

International Rectifier IRG4PH40K // 1200V // 30A continuous @25°C // 60A peak


(https://www.richis-lab.de/images/Transistoren/59x02.jpg)

(https://www.richis-lab.de/images/Transistoren/59x03.jpg)

I had a second one. The marking looked quite strange but it seems to be a genuine part because it has the same dies as the first one.


(https://www.richis-lab.de/images/Transistoren/59x04.jpg)

Interesting, the gate potential distribution lines are not symmetrical.
The die is 6,2mm x 4,3mm. It´s smaller than the die of the IXYS IXGH48N60C3D1 (7,2mm x 6,1mm / https://www.richis-lab.de/Bipolar26.htm (https://www.richis-lab.de/Bipolar26.htm)) because it has to conduct less current. The IRG4PH40K has a bigger field control area because of the much higher voltage rating.
The brownish coating seems to be a protective layer.


(https://www.richis-lab.de/images/Transistoren/59x05.jpg)

(https://www.richis-lab.de/images/Transistoren/59x06.jpg)

Gate potential distribution over the silicon.


(https://www.richis-lab.de/images/Transistoren/59x07.jpg)

The field control looks interesting. In the corners the metal lines are a little wider and there is a via connecting the silicon underneath.
While most of the field control is coated the first two isolation gaps are left blank.


(https://www.richis-lab.de/images/Transistoren/59x08.jpg)

(https://www.richis-lab.de/images/Transistoren/59x09.jpg)

The marking on the die is mirror inverted. => 1997


(https://www.richis-lab.de/images/Transistoren/59x11.jpg)

(https://www.richis-lab.de/images/Transistoren/59x12.jpg)

And that´s the HEXFRED (4,0mm x 3,0mm).


(https://www.richis-lab.de/images/Transistoren/59x13.jpg)

Field control like on the IGBT.
In the active area there is a honeycomb structure.


https://www.richis-lab.de/Bipolar35.htm (https://www.richis-lab.de/Bipolar35.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: exe on January 15, 2021, 09:31:56 pm
I have a FRED in stock.

You mean FERD, right? I'm in great anticipation! There is very little info on these beasts.

While searching for info, it seems there a newer generation called cc-ferd: https://www.semanticscholar.org/paper/A-New-Generation-of-Power-Diode%3A-Charge-Coupled-Lee-Ngwan/724f82fd90cbea5b81bb116e646b7105117ca701 (https://www.semanticscholar.org/paper/A-New-Generation-of-Power-Diode%3A-Charge-Coupled-Lee-Ngwan/724f82fd90cbea5b81bb116e646b7105117ca701) . I'm trying to find a full paper. Although, looking at research papers, there seems to be many ideas, but few make into silicon.

UP: found pdf scholar.google.com
Title: Re: Transistors - die pictures
Post by: Noopy on January 16, 2021, 04:17:48 am
I have a FRED in stock.

You mean FERD, right? I'm in great anticipation! There is very little info on these beasts.

While searching for info, it seems there a newer generation called cc-ferd: https://www.semanticscholar.org/paper/A-New-Generation-of-Power-Diode%3A-Charge-Coupled-Lee-Ngwan/724f82fd90cbea5b81bb116e646b7105117ca701 (https://www.semanticscholar.org/paper/A-New-Generation-of-Power-Diode%3A-Charge-Coupled-Lee-Ngwan/724f82fd90cbea5b81bb116e646b7105117ca701) . I'm trying to find a full paper. Although, looking at research papers, there seems to be many ideas, but few make into silicon.

UP: found pdf scholar.google.com

FRED, FERD,... ;D
Yes, I wanted to write FERD: https://www.mouser.de/ProductDetail/STMicroelectronics/FERD40H100SFP/?qs=ZSypp649SOX1Ct15PSJtkQ%3D%3D (https://www.mouser.de/ProductDetail/STMicroelectronics/FERD40H100SFP/?qs=ZSypp649SOX1Ct15PSJtkQ%3D%3D)
CC-FERD, interesting...
Title: Re: Transistors - die pictures
Post by: Noopy on January 18, 2021, 03:30:49 pm
(https://www.richis-lab.de/images/Transistoren/60x01.jpg)

Siliconix 2N5911 (1978)


(https://www.richis-lab.de/images/Transistoren/60x02.jpg)

The 2N5911 contains two sorted J-FETs with one dedicated pin contacting the package.


(https://www.richis-lab.de/images/Transistoren/60x03.jpg)

Hey that´s absolutely the same as the DN1682 (https://www.richis-lab.de/FET06.htm (https://www.richis-lab.de/FET06.htm), 1986).
The dies are placed on the flattened gate-pins.


(https://www.richis-lab.de/images/Transistoren/60x04.jpg)

(https://www.richis-lab.de/images/Transistoren/60x05.jpg)

Yeah, that are exactly the same J-FETs.
As described with the DN1682 I assume the numbers are for sorting the dies.


https://www.richis-lab.de/FET10.htm (https://www.richis-lab.de/FET10.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on January 19, 2021, 01:49:50 am
Ha, the gate connection for a JFET is through the substrate but that is also a point of failure so they added a bond wire in parallel.
Title: Re: Transistors - die pictures
Post by: Noopy on January 19, 2021, 04:11:24 am
Ha, the gate connection for a JFET is through the substrate but that is also a point of failure so they added a bond wire in parallel.

In addition the bond wire reduces the gate impedance.
Title: Re: Transistors - die pictures
Post by: David Hess on January 22, 2021, 05:45:21 pm
Ha, the gate connection for a JFET is through the substrate but that is also a point of failure so they added a bond wire in parallel.

In addition the bond wire reduces the gate impedance.

The connection through the substrate is much lower impedance than the bond wire, which also goes to the substrate.

The problem is that the substrate connection through the bottom of the die is difficult to make reliably.  There are examples of this in the past from National and Tektronix where the substrate connection became intermittent with temperature but the transistor still worked because of capacitive coupling, except of course when it did not.
Title: Re: Transistors - die pictures
Post by: Noopy on January 22, 2021, 07:07:00 pm
Ha, the gate connection for a JFET is through the substrate but that is also a point of failure so they added a bond wire in parallel.

In addition the bond wire reduces the gate impedance.

The connection through the substrate is much lower impedance than the bond wire, which also goes to the substrate.

The problem is that the substrate connection through the bottom of the die is difficult to make reliably.  There are examples of this in the past from National and Tektronix where the substrate connection became intermittent with temperature but the transistor still worked because of capacitive coupling, except of course when it did not.

Are you sure? I thought silicon has always more resistance than metal? OK, the die is much thicker and shorter than the bondwire but nevertheless...
It's hard to believe they bonded a wire just in case the substrate connection fails. The behaviour would change all the same.
Title: Re: Transistors - die pictures
Post by: Noopy on January 23, 2021, 12:37:30 pm
(https://www.richis-lab.de/images/Transistoren/61x01.jpg)

Finally we have a Dual-Gate-MOSFET: Motorla MFE122


(https://www.richis-lab.de/images/Transistoren/61x03.jpg)

Source is connected to the case.


(https://www.richis-lab.de/images/Transistoren/61x05.jpg)

(https://www.richis-lab.de/images/Transistoren/61x06.jpg)

(https://www.richis-lab.de/images/Transistoren/61x07.jpg)

The innermost metal structure is the drain contact. Around the drain we have gate 2 and gate 1 followed by the source contact.
The gate 1 electrode is smaller than the gate 2 electrode. I doesn´t look like an accident. Perhaps the gate 1 capacitance was lowered a little by using the smaller electrode.
Under the gate bondpads there are additional structures. Probably that are the gate protection diodes.


https://www.richis-lab.de/FET11.htm (https://www.richis-lab.de/FET11.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on January 27, 2021, 01:00:22 am
Ha, the gate connection for a JFET is through the substrate but that is also a point of failure so they added a bond wire in parallel.

In addition the bond wire reduces the gate impedance.

The connection through the substrate is much lower impedance than the bond wire, which also goes to the substrate.

The problem is that the substrate connection through the bottom of the die is difficult to make reliably.  There are examples of this in the past from National and Tektronix where the substrate connection became intermittent with temperature but the transistor still worked because of capacitive coupling, except of course when it did not.

Are you sure? I thought silicon has always more resistance than metal? OK, the die is much thicker and shorter than the bondwire but nevertheless...
It's hard to believe they bonded a wire just in case the substrate connection fails. The behaviour would change all the same.

For a JFET the substrate connection goes to the gate so any series resistance is inconsequential, unless it becomes very high.  And even when open, many circuits will still work because of capacitive coupling.

Title: Re: Transistors - die pictures
Post by: Noopy on January 27, 2021, 05:49:24 am
For a JFET the substrate connection goes to the gate so any series resistance is inconsequential, unless it becomes very high.  And even when open, many circuits will still work because of capacitive coupling.

Basically I agree with you. I´m just not sure whether that is unlimited true for matched HF-transistors. At 100MHz there will flow some 10mA over the gate and bad or "high resistance" connections will degrade the matching.
Title: Re: Transistors - die pictures
Post by: Noopy on January 28, 2021, 06:05:14 pm
(https://www.richis-lab.de/images/Transistoren/62x01.jpg)

Sescosem 2N3054


(https://www.richis-lab.de/images/Transistoren/62x02.jpg)

Some white potting on top of the transistor die.


(https://www.richis-lab.de/images/Transistoren/62x03.jpg)

There are some residues but it should be ok...


(https://www.richis-lab.de/images/Transistoren/62x05.jpg)

Yes, it´s a MESA-Transistor.


(https://www.richis-lab.de/images/Transistoren/62x04.jpg)

Nothing special but...


(https://www.richis-lab.de/images/Transistoren/62x06.jpg)

(https://www.richis-lab.de/images/Transistoren/62x07.jpg)

It seems they had problems with the mask alignment.  :o


https://www.richis-lab.de/Bipolar36.htm (https://www.richis-lab.de/Bipolar36.htm)

 :popcorn:
Title: Re: Transistors - die pictures
Post by: Noopy on January 30, 2021, 12:51:32 pm
Today a small one:


(https://www.richis-lab.de/images/Transistoren/63x01.jpg)

Ferranti ZTX108C


(https://www.richis-lab.de/images/Transistoren/63x03.jpg)

That´s an interesting contact design. The base electrodes lead around the emitter bond and contact the base area in the lower corners. I assume there is also a contact under the base bondpad. The emitter electrode is kind of U-shaped.
The edge length is 0,37mm. It´s always a lot of fun to find such a small die in the burned remains of the mold. Then you have to clean it and bring it in the front of the camera in the right orientation. If the small thing leaps down the tweezer you often can´t find it again.  :o


https://www.richis-lab.de/Bipolar37.htm (https://www.richis-lab.de/Bipolar37.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: dzseki on February 05, 2021, 09:12:17 pm
Sorry I don't want to hijack the thread but it is somewhat relevant and I hope you find this interesting as well.
At work we use some temperature sensor diodes those are suitable measuring between 1.4K-500K temperatures, with reasonable precision (up to +/-0.25K at low temperatures). Needless to say these can be stupidly expensive, so interesting to take them apart :)

One such example is the Lakeshore DT-670 series:
https://www.lakeshore.com/products/categories/overview/temperature-products/cryogenic-temperature-sensors/dt-670-silicon-diodes (https://www.lakeshore.com/products/categories/overview/temperature-products/cryogenic-temperature-sensors/dt-670-silicon-diodes)

One can find these in many flavours, even in 'bare die' configuration.
(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1166082;image)
Here you can see this is in fact a transistor's C-B diode that is used for temperature sensing. It would be nice to find out which transistor could this be -roughly. It is possible that this is somewhat a custom part made by 3rd party vendor, but then why would they hassle with transistor structure when only a diode is needed?
Obviously the very precise pieces are heavily binned so I don't think there is a free meal here, but still it would be nice to get a rough idea on the source.
Here is a self made shot too of such die (not as nice as you are use to it, sorry):
(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1166078;image)
Title: Re: Transistors - die pictures
Post by: Noopy on February 05, 2021, 11:19:27 pm
That´s an interesting story.

Here you can see this is in fact a transistor's C-B diode that is used for temperature sensing. It would be nice to find out which transistor could this be -roughly. It is possible that this is somewhat a custom part made by 3rd party vendor, but then why would they hassle with transistor structure when only a diode is needed?
Obviously the very precise pieces are heavily binned so I don't think there is a free meal here, but still it would be nice to get a rough idea on the source.

Well I´m definitely no expert for low temperature meassurements but I agree with you. Probably that´s a "normal" transistor. Of course the transistor is chosen so it is well suited for the temperature meassurement and I also assume they did a lot of binning but probably it´s a "normal" transistor.

Up to now I haven´t seen such a structure...  :-//
Title: Re: Transistors - die pictures
Post by: SilverSolder on February 05, 2021, 11:36:00 pm

It seems a surprisingly big transistor for temperature measurement, wonder what drove that decision?

And why the C-B diode instead of the B-E one?
Title: Re: Transistors - die pictures
Post by: dzseki on February 08, 2021, 09:43:02 pm
Well, I have seen similar structure on your pictures! On your OPA676 die pictures.

I only assume that the C-B diode is used because the Collector itself represents the die, so if there is some gradient (and at low temperatures there is) the the bigger sensing area might give more sensible reading. To reach cryogenic temperatures from room temperature takes usualy at least a hour or so, so fast response time is less of a concern.
Title: Re: Transistors - die pictures
Post by: Noopy on February 09, 2021, 04:29:59 am
Hm... The transistors look related but on this level all transistors look related... I wouldn´t state these are brothers...  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on February 11, 2021, 07:56:27 pm
(https://www.richis-lab.de/images/Transistoren/64x01.jpg)

Hitachi 2SK1317, breakdown voltage 1500V, 2,5A continuously, 7,5A peak.


(https://www.richis-lab.de/images/Transistoren/64x02.jpg)

Well I have taken better pictures... The package is quite tough and the die has a polyimid like coating.
The edge length is 5,4mm.


(https://www.richis-lab.de/images/Transistoren/64x03.jpg)

We have the usual potential steering but less rings than in the 1000V-BUK466 (https://www.richis-lab.de/FET07.htm (https://www.richis-lab.de/FET07.htm)).


(https://www.richis-lab.de/images/Transistoren/64x04.jpg)

There is quite some free space between the transistors.


https://www.richis-lab.de/FET12.htm (https://www.richis-lab.de/FET12.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on February 12, 2021, 08:02:25 am
Could you please remind me what are those rings around the transistor?
Title: Re: Transistors - die pictures
Post by: Noopy on February 12, 2021, 10:37:39 am
Could you please remind me what are those rings around the transistor?

That is field steering to get a more uniform electrical field and in consequence less isolation stress.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on February 16, 2021, 06:37:45 pm
(https://www.richis-lab.de/images/Transistoren/65x01.jpg)

Philips MPSA56, a pnp transistor.
They marked emitter, base and collector, nice!  :-+


(https://www.richis-lab.de/images/Transistoren/65x02.jpg)

0,6mm x 0,6mm, quite a big die for a small signal transistor. Well, it can conduct 500mA, 1Apeak.  :-+


https://www.richis-lab.de/Bipolar38.htm (https://www.richis-lab.de/Bipolar38.htm)

 :-+
Title: Re: Transistors - die pictures
Post by: David Hess on February 16, 2021, 10:58:56 pm
Philips MPSA56, a pnp transistor.

On Semiconductor makes it also and isn't MPS or MPSA a Motorola prefix?

It is so similar to the 2N4403 that I wonder why it even exists.  It is slightly slower but slightly higher voltage so I wonder if it is just a graded 2N4403.
Title: Re: Transistors - die pictures
Post by: Noopy on February 17, 2021, 05:23:26 am
Philips MPSA56, a pnp transistor.

On Semiconductor makes it also and isn't MPS or MPSA a Motorola prefix?

It is so similar to the 2N4403 that I wonder why it even exists.  It is slightly slower but slightly higher voltage so I wonder if it is just a graded 2N4403.

There are also MPSA transistors built by Philips. The one who gave me these transistors stated it is a Philips...  :-//
Title: Re: Transistors - die pictures
Post by: exe on February 17, 2021, 09:17:18 am
It is so similar to the 2N4403 that I wonder why it even exists.

Can it be a "European" equivalent of 2n4403? Like 2n3904 and bc548. Anyway, I'm pretty sure there are more part numbers than design variations. I bought BD135G, BD137G and BD139G (don't remember the vendor, there are several companies producing supplying them) and measured them with transistor tester and with siggen for gain vs freq. They all had very close gain and base drop voltage, which I interpret that they are the same design.
Title: Re: Transistors - die pictures
Post by: Noopy on February 18, 2021, 12:33:08 pm
Here we have a complementary pair BC550C / B560C built by Philips:


(https://www.richis-lab.de/images/Transistoren/66x01.jpg)

(https://www.richis-lab.de/images/Transistoren/66x02.jpg)

(https://www.richis-lab.de/images/Transistoren/66x04.jpg)

The BC550C-die is 0,26mm x 0,27mm. Luckily the die sticked on the leadframe so it was easier to put it in front of the camera.


(https://www.richis-lab.de/images/Transistoren/67x01.jpg)

(https://www.richis-lab.de/images/Transistoren/67x02.jpg)

(https://www.richis-lab.de/images/Transistoren/67x03.jpg)

The BC560C die is bigger than the NPN BC550C: 0,32mm x 0,32mm. That´s plausible because PNP transistors in principle have worse specifications than NPN transistors. Well, we don´t know if these two transistors are different generations but the different size is plausible. You also can see different collector capacities in the datasheets: BC550C: 1,5pF / BC560C: 4pF

https://www.richis-lab.de/Bipolar39.htm (https://www.richis-lab.de/Bipolar39.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on February 18, 2021, 05:41:18 pm
For some reason I like small bjts. They are small, fast and cheap. And if you need more power just use them in parallel (I'm kidding).
Title: Re: Transistors - die pictures
Post by: David Hess on February 19, 2021, 10:03:38 pm
There are also MPSA transistors built by Philips. The one how gave me these transistors stated it is a Philips...  :-//

I know others make MPS and MPSA prefix transistors.  I just thought that prefix originated with Motorola and others are second sources.

Can it be a "European" equivalent of 2n4403? Like 2n3904 and bc548. Anyway, I'm pretty sure there are more part numbers than design variations. I bought BD135G, BD137G and BD139G (don't remember the vendor, there are several companies producing supplying them) and measured them with transistor tester and with siggen for gain vs freq. They all had very close gain and base drop voltage, which I interpret that they are the same design.

I do not think so.  As far as I know, the BC series may be similar in function and application but are of a completely different origin of design, at least originally, then the 2N series.  The specifications for the 2N3904 and BC548 do not match at all.
Title: Re: Transistors - die pictures
Post by: Noopy on February 20, 2021, 05:45:33 am
There are also MPSA transistors built by Philips. The one who gave me these transistors stated it is a Philips...  :-//

I know others make MPS and MPSA prefix transistors.  I just thought that prefix originated with Motorola and others are second sources.

You are right, Philips was definitely not the first one selling the MPSA56 but certainly this MPSA56 is a "Philips-MPSA".  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on February 21, 2021, 08:53:01 pm
(https://www.richis-lab.de/images/Transistoren/68x01.jpg)

Valvo ASZ16, a PNP-Ge-Powertransistor (32V, 10A, 250kHz).
The TO-3 package is interesting: The base plate is quite big. The datasheet states 3,4mm. But the cap is quite low (3,6mm).


(https://www.richis-lab.de/images/Transistoren/68x02.jpg)

Valvo not only mounted a dehumidifying element in the package, they also potted the free room with a silicone gel like material.


(https://www.richis-lab.de/images/Transistoren/68x03.jpg)

Meanwhile we know the stackup of a Ge-Powertransistors.


(https://www.richis-lab.de/images/Transistoren/68x04.jpg)

There are isolating plates on the contact pins. Probably that makes fabrication easier.


(https://www.richis-lab.de/images/Transistoren/68x05.jpg)

 :-+


https://www.richis-lab.de/Bipolar40.htm (https://www.richis-lab.de/Bipolar40.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 25, 2021, 11:23:39 am
(https://www.richis-lab.de/images/Transistoren/70x01.jpg)

Siemens BC239C


(https://www.richis-lab.de/images/Transistoren/70x03.jpg)

(https://www.richis-lab.de/images/Transistoren/70x02.jpg)

Nothing special...


https://www.richis-lab.de/Bipolar41.htm (https://www.richis-lab.de/Bipolar41.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 01, 2021, 07:08:47 pm
(https://www.richis-lab.de/images/Transistoren/71x01.jpg)

The BUX66 is a pnp power transistor capable of isolating up to 350V and conducting up to 2A, 5Apeak.
They did quite some binning:
BUX66 150V
BUX66A 250V
BUX66B 300V
BUX66C 350V
This BUX66 built by Motorola seems to be quite new: 2005.


(https://www.richis-lab.de/images/Transistoren/71x02.jpg)

(https://www.richis-lab.de/images/Transistoren/71x03.jpg)

There is some silicone like potting on the die but the amount of potting is quite different in these two transistors.


(https://www.richis-lab.de/images/Transistoren/71x04.jpg)

Some damage due to the depotting...  :'(


(https://www.richis-lab.de/images/Transistoren/71x05.jpg)

The die is 3,6mm x 3,0mm.


(https://www.richis-lab.de/images/Transistoren/71x06.jpg)

It´s a MESA transistor with a nice trench at the edges of the die.


(https://www.richis-lab.de/images/Transistoren/71x07.jpg)

The structure is interesting. The left brown area is the p-doped emitter. The following green are is the n-doped base. In the next pictures we will see that this is the base-emitter-junction.
Before the base contact there is a small brown p-doped layer certainly above the base area. Why that? Looks like a pinch resistor to increase the base resistance. But why would they increase the base resistance? Perhaps the resistance is equalising the electric stress on the transistor area?  :-//


(https://www.richis-lab.de/images/Transistoren/71x08.jpg)

That´s the base emitter junction!  8)
(13,5V / 20mA)


(https://www.richis-lab.de/images/Transistoren/71x10.jpg)

Looks like a very uniform transistor structure.


(https://www.richis-lab.de/images/Transistoren/71x11.jpg)

0,8A  8)


https://www.richis-lab.de/Bipolar42.htm (https://www.richis-lab.de/Bipolar42.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 02, 2021, 04:52:39 am
(https://www.richis-lab.de/images/Transistoren/71x01.jpg)

Today I´m pretty sure that´s a conterfeit part:
- 2005 Motorola was already ON Semiconductor.
- In the "Motorola Semiconductor Master Selection Guide 1994" there is already no TO-66 package left.
- Up to now I found such a white potting just in the conterfeit BUX22 (https://www.richis-lab.de/Bipolar09.htm (https://www.richis-lab.de/Bipolar09.htm)) and in the Inchange 3DD15D (https://www.richis-lab.de/Bipolar05.htm (https://www.richis-lab.de/Bipolar05.htm))
- The strange additional "ring" between base and emitter was also only found in the conterfeit BUX22 and in the Inchange 3DD15D.

 >:D
Title: Re: Transistors - die pictures
Post by: exe on March 02, 2021, 11:26:55 am
I was about to say how well it's made :).

Perhaps there are many manufacturer in Asia that I've never heard of and who are producing parts like that (assuming it's from China). I found many parts that are absolete but yet cloned/produced/available. Like some jfets for mic pre-amps.
Title: Re: Transistors - die pictures
Post by: SilverSolder on March 02, 2021, 03:38:05 pm
(https://www.richis-lab.de/images/Transistoren/71x01.jpg)

Today I´m pretty sure that´s a conterfeit part:
- 2005 Motorola was already ON Semiconductor.
- In the "Motorola Semiconductor Master Selection Guide 1994" there is already no TO-66 package left.
- Up to now I found such a white potting just in the conterfeit BUX22 (https://www.richis-lab.de/Bipolar09.htm (https://www.richis-lab.de/Bipolar09.htm)) and in the Inchange 3DD15D (https://www.richis-lab.de/Bipolar05.htm (https://www.richis-lab.de/Bipolar05.htm))
- The strange additional "ring" between base and emitter was also only found in the conterfeit BUX22 and in the Inchange 3DD15D.

 >:D

Maybe the clean and uniform transistor structure that you found in the original post is a sign that it has been manufactured with a more modern process than the original?

Perhaps we ought to set up a "Counterfeit Test Program" to reveal which counterfeits are, in fact, quite good,  and which are not good?   :D
Title: Re: Transistors - die pictures
Post by: Noopy on March 02, 2021, 05:12:17 pm
This BUX66 definitely looks like a big good transistor.  :-+ Nevertheless it is a conterfeit part... But maybe good to use.  :-//

Testing these transistors would be very interesting but would need a lot more time and equipment.  :-\
Title: Re: Transistors - die pictures
Post by: Noopy on March 03, 2021, 12:27:16 pm
Siemens BC239C


(https://www.richis-lab.de/images/Transistoren/69x01.jpg)

Today: Philips BC239C


(https://www.richis-lab.de/images/Transistoren/69x02.jpg)

(https://www.richis-lab.de/images/Transistoren/69x03.jpg)

Interesting: The Philips BC239C looks exactly the same as the Siemens BC239C, same structures, same size!
I had to look twice because in the first place I wasn´t perfectly sure if I really had taken the Philips die and not the Siemens die by accident. But now I´m sure the Philips die is the same as the Siemens die.


https://www.richis-lab.de/Bipolar41.htm (https://www.richis-lab.de/Bipolar41.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 06, 2021, 08:47:38 pm
(https://www.richis-lab.de/images/Transistoren/72x01.jpg)

Motorola 2N2152, a Ge-PNP-Powertransistor: 30V, 30A, 2kHz. There are two more bins giving you 45V and 60V.
The 2N2152 is especially interesting compared to the 15A-line around the 2N2081 (https://www.richis-lab.de/Bipolar28.htm (https://www.richis-lab.de/Bipolar28.htm)).


(https://www.richis-lab.de/images/Transistoren/72x03.jpg)

The huge TO-36-packages makes 170W (@25°C) possible.  8)


(https://www.richis-lab.de/images/Transistoren/72x05.jpg)

A metal ring is carrying a n-doped germanium disk which is the base. On both sides of the disk there is an alloyed area giving you p-dopant for emitter and collector.


(https://www.richis-lab.de/images/Transistoren/72x06.jpg)

But wait! While in the 2N2081 there is a second base contact in the middle of the disk here it is missing. That explains the higher collector current (30A vs. 15A). The disk diameter is exactly the  same in the 2N2152 and in the 2N2081 but without the central base contact you have a much bigger emitter area. The drawback is a lower cutoff frequency (2kHz vs. 5kHz) since the base impedance is higher.


(https://www.richis-lab.de/images/Transistoren/72x07.jpg)

Quite a big emitter contact!  :-+


https://www.richis-lab.de/Bipolar43.htm (https://www.richis-lab.de/Bipolar43.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 09, 2021, 09:06:21 am
Some more transistor dust!  ;D


(https://www.richis-lab.de/images/Transistoren/73x01.jpg)

BC547C, pretty the same as the BC550 (https://www.richis-lab.de/Bipolar39.htm (https://www.richis-lab.de/Bipolar39.htm)) but the maximum noise figure is a bit higher: 10dB vs. 4dB
The base-emitter-junction is a little bit more robust: -6V vs. -5V. Probably the base doping of the BC550 is a bit higher. That gives you lower base resistance which gives you lower thermal noise but also reduces the base emitter breakdown voltage.


(https://www.richis-lab.de/images/Transistoren/73x02.jpg)

(https://www.richis-lab.de/images/Transistoren/73x03.jpg)

Hey, that´s exactly the same die as in the BC550 (https://www.richis-lab.de/Bipolar39.htm (https://www.richis-lab.de/Bipolar39.htm))! It seems like they just did some binning.
A die with 0,27mm edge length is really fun to handle.  >:D


https://www.richis-lab.de/Bipolar44.htm (https://www.richis-lab.de/Bipolar44.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 11, 2021, 06:20:59 pm
(https://www.richis-lab.de/images/Transistoren/74x01.jpg)

(https://www.richis-lab.de/images/Transistoren/74x02.jpg)

Today something new: Rohm DTC114, a digital transistor.


(https://www.richis-lab.de/images/Transistoren/74x04.jpg)

The die is 0,35mm x 0,35mm.


(https://www.richis-lab.de/images/Transistoren/74x05.jpg)

(https://www.richis-lab.de/images/Transistoren/74x06.jpg)

Well that´s quite clear.  :-+
Interesting point: The resistors have a different color. They probably used a special material to get the high resistance in this small area.


https://www.richis-lab.de/Bipolar45.htm (https://www.richis-lab.de/Bipolar45.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on March 11, 2021, 10:43:54 pm
Y'know, I don't think I ever tested one of those for Vbc.  I suppose the resistors are on top of oxide, not diffused into the collector, so that wouldn't matter.  I wonder if amorphous or poly-Si, or metal or what?

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on March 12, 2021, 04:17:20 am
I had the same opinion. Probably it´s some lower doped polysilicon. I assume the resistance of metal would be to low.

One would need to curve trace Vbc vs. Ibc to see the resistor... ...or not...  :-/O
Title: Re: Transistors - die pictures
Post by: exe on March 13, 2021, 09:28:19 am
The die is 0,35mm x 0,35mm.

Still can't wrap my head around how they cut and pack such tiny dies. Is it laser-cut yet or still cut by a saw? The BC547C has rough edges, I'd assume that one was cut by a saw.
Title: Re: Transistors - die pictures
Post by: Noopy on March 13, 2021, 10:38:44 am
Well I don´t know...  :-//
Title: Re: Transistors - die pictures
Post by: capt bullshot on March 13, 2021, 12:45:58 pm
Well I don´t know...  :-//

I vaguely remember, the wafer gets scribed along the lines between the dice, then attached to some elastic material and pulled apart to separate the dice.

Title: Re: Transistors - die pictures
Post by: Miyuki on March 15, 2021, 05:56:52 pm
Well I don´t know...  :-//

I vaguely remember, the wafer gets scribed along the lines between the dice, then attached to some elastic material and pulled apart to separate the dice.
So like most brittle materials (glass, ceramic)
Makes sense
No mess and waste
Title: Re: Transistors - die pictures
Post by: Noopy on March 17, 2021, 10:21:12 pm
(https://www.richis-lab.de/images/Transistoren/75x01.jpg)

Tesla KD605, a NPN-Powertransistor for linear operation like the KD501 (https://www.richis-lab.de/Bipolar02.htm (https://www.richis-lab.de/Bipolar02.htm)).
Both the KD501 and the KD605 can isolate 40V but the KD501 can conduct 20A compared to 10A for the KD605. Also the maximum power dissipation is quite different: 150W vs. 70W. Surprisingly the dies in the packages look the same. Probably the more massive package of the KD501 gives you a lot more power. Perhaps there was also some binning.


(https://www.richis-lab.de/images/Transistoren/75x04.jpg)

The die is potted with some red silicone like material.
The die of the KD501 is soldered directly to the package. Here there is a round carrier.


(https://www.richis-lab.de/images/Transistoren/75x06.jpg)

Looks similar to the KD501.


(https://www.richis-lab.de/images/Transistoren/75x07.jpg)

Besides the MESA structure we see kind of a step at the uppermost layer. That could be the collector base junction but more likely it is an isolating silicon oxide layer.


(https://www.richis-lab.de/images/Transistoren/75x08.jpg)

(https://www.richis-lab.de/images/Transistoren/75x09.jpg)

Interesting, there are some very small steps in the base-emitter-junction.


(https://www.richis-lab.de/images/Transistoren/75x10.jpg)

 8)
-9V / 100mA


(https://www.richis-lab.de/images/Transistoren/75x11.jpg)

1A


https://www.richis-lab.de/Bipolar46.htm (https://www.richis-lab.de/Bipolar46.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: daqq on March 17, 2021, 10:37:09 pm
Thanks for the great work!
Perhaps there was also some binning.
Yup, this was likely the case. Legend has it that Tesla did not gave great process yields or repeatability and they did a lot of binning for semiconductors.

An interesting analysis would be a silicon capacitor ( https://www.mouser.sk/Passive-Components/Capacitors/Silicon-RF-Capacitors-Thin-Film/_/N-5g95 (https://www.mouser.sk/Passive-Components/Capacitors/Silicon-RF-Capacitors-Thin-Film/_/N-5g95) ). Some seem to have far more advanced structures on them :)
Title: Re: Transistors - die pictures
Post by: Noopy on March 17, 2021, 10:47:55 pm
Thanks for the great work!

Thanks!  8)


Perhaps there was also some binning.
Yup, this was likely the case. Legend has it that Tesla did not gave great process yields or repeatability and they did a lot of binning for semiconductors.

But I assume besides the binning the more massive package has also some effect.


An interesting analysis would be a silicon capacitor ( https://www.mouser.sk/Passive-Components/Capacitors/Silicon-RF-Capacitors-Thin-Film/_/N-5g95 (https://www.mouser.sk/Passive-Components/Capacitors/Silicon-RF-Capacitors-Thin-Film/_/N-5g95) ). Some seem to have far more advanced structures on them :)


Sounds interesting! I´ll put them on my list.  :-+



Title: Re: Transistors - die pictures
Post by: SilverSolder on March 17, 2021, 10:48:45 pm
[...]Tesla KD605[...]

So who's hiding inside that transistor, then?  :D

(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1196250;image)
Title: Re: Transistors - die pictures
Post by: Noopy on March 17, 2021, 10:53:15 pm
So who's hiding inside that transistor, then?  :D

 ;D
Title: Re: Transistors - die pictures
Post by: Noopy on March 20, 2021, 09:11:01 pm
(https://www.richis-lab.de/images/Transistoren/75x01.jpg)

https://www.richis-lab.de/Bipolar46.htm (https://www.richis-lab.de/Bipolar46.htm)

I have to correct myself: The die of the KD605 is a little smaller than the die of the KD601: 4,5mm vs. 5,5mm edge length. I have lost one mm.  ::) But that doesn´t explain the lower power rating completely...
Title: Re: Transistors - die pictures
Post by: Noopy on March 22, 2021, 08:26:27 am
(https://www.richis-lab.de/images/Transistoren/76x01.jpg)

The STMicroelectronics VN820 is a Highside Smart-MOSFET of the third generation "M0-3".
The VN02H (https://www.richis-lab.de/FET02.htm (https://www.richis-lab.de/FET02.htm)) is of the first generation "M0-1".
The VN820 gives you 9A at 40m \$\Omega\$. Maximum isolation voltage is 55V (Clamping).


(https://www.richis-lab.de/images/Transistoren/76x03.jpg)

The die is 3,2mm x 2,6mm.


(https://www.richis-lab.de/images/Transistoren/76x04.jpg)

The design is named VN82B and was created in the year 2000.


(https://www.richis-lab.de/images/Transistoren/76x14.jpg)

The die is divided in two pieces.
The power transistor (red) is integrated in the same frame as the driver circuit (purple). They share the source potential as reference.
The second frame shares the GND potential as reference. In this frame there is the control circuit and the Vcc clamp which protects the devices against overvoltages on the supply line.
The main power transistor connects Vcc (substrate) to Output. The Vcc-Clamp connects Vcc (substrate) to GND.


(https://www.richis-lab.de/images/Transistoren/76x09.jpg)

An interesting connection between the two areas.


(https://www.richis-lab.de/images/Transistoren/76x10.jpg)

In the driver area there are some capacitors some probably storing the energy to charge the gate of the output transistor.
It seems like there are also some protection circuits in this area to keep reaction time short.


(https://www.richis-lab.de/images/Transistoren/76x11.jpg)

There are two small current sensing transistors. One transistor is connected to the driver circuits, one transistor is connected to the control circuit. The control circuit needs the current value for open load detection. The VN920 gives you a current sense output. Perhaps they use the same die.


(https://www.richis-lab.de/images/Transistoren/76x06.jpg)

Well the power transistor is a big MOSFET.  ;D
In the corners there are free squares. That looks like electrical field steering but I don´t think that is what these structures are for.


(https://www.richis-lab.de/images/Transistoren/76x13.jpg)

The control circuit and the Vcc clamp.


Some more pictures here:

https://www.richis-lab.de/FET13.htm (https://www.richis-lab.de/FET13.htm)
Title: Re: Transistors - die pictures
Post by: Noopy on March 26, 2021, 09:35:10 pm
(https://www.richis-lab.de/images/Transistoren/77x01.jpg)

The Siliconix VN88 is an old Power-MOSFET.


(https://www.richis-lab.de/images/Transistoren/77x02.jpg)

(https://www.richis-lab.de/images/Transistoren/77x03.jpg)

The die is 1,8mm x 1,0mm and was protected with a silicone like potting.


(https://www.richis-lab.de/images/Transistoren/77x04.jpg)

That´s an interesting die marking.


(https://www.richis-lab.de/images/Transistoren/77x05.jpg)

There is a small resistor between the gate bondpad and the gates. The surrounding area is connected quite massive to the source. Probably that is a zener protecting the gate-source-isolation.  :-+


https://www.richis-lab.de/FET14.htm (https://www.richis-lab.de/FET14.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on March 26, 2021, 09:48:43 pm
Interesting, they don't show the zener, at least in the -AFD (TO-220) version, at least in the Vishay/Siliconix datasheet from 2001.

Not sure if that's V-groove (VMOS innit?) or trench (VDMOS?), definitely not lateral in any case!

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on March 26, 2021, 09:52:43 pm
Nothing in the datassheet. I found that interesting too!  :-+

Some people state it is a VMOS...
Title: Re: Transistors - die pictures
Post by: vishkas on March 27, 2021, 03:23:06 am
Looks Interesting
Title: Re: Transistors - die pictures
Post by: Noopy on March 27, 2021, 07:39:31 pm
(https://www.richis-lab.de/images/Transistoren/78x01.jpg)

The П217Б (P217B) is an old germanium power transistor built by Pluton, a company you can still find in moscow. (Thanks to serg-el for the hint!)
45V / 7,5A / 30W


(https://www.richis-lab.de/images/Transistoren/78x02.jpg)

That is a package you don´t see every day.


(https://www.richis-lab.de/images/Transistoren/78x04.jpg)

In the package we find a lot of dehumidifying powder.


(https://www.richis-lab.de/images/Transistoren/78x05.jpg)

Well meanwhile we know these transistor stackups.


https://www.richis-lab.de/Bipolar47.htm (https://www.richis-lab.de/Bipolar47.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 30, 2021, 08:37:55 pm
(https://www.richis-lab.de/images/Transistoren/81x01.jpg)

The Ferranti ZTX312 is a transistor which switches quite fast: ton=20ns, toff=15ns
That makes it interesting to compare it with the general purpose ZTX108C (https://www.richis-lab.de/Bipolar37.htm (https://www.richis-lab.de/Bipolar37.htm))


(https://www.richis-lab.de/images/Transistoren/81x02.jpg)

(https://www.richis-lab.de/images/Transistoren/81x03.jpg)

Nice, there is an E to recognise the emitter.  ;D
The die is 0,44mm x 0,44mm. The active area is just 0,11mm x 0,09mm. With two emitter areas and three base contacts the transistor gets quite fast.
Interesting point: The ZTX312 allows 500mA while the ZTX108C is specified with just 100mA. A drawback of the ZTX312 is the lower amplification (less than a tenth of the ZTX108C).


https://www.richis-lab.de/Bipolar49.htm (https://www.richis-lab.de/Bipolar49.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Gyro on March 30, 2021, 08:46:29 pm
I think you may find that the 'E' stands for E-line.  ;) This family dates back to the Ferranti E-Line series.

They use a Silicone rather than Epoxy packaging material, allowing higher junction temperatures and dissipations than TO92. They were used a lot in Mil spec equipment.
Title: Re: Transistors - die pictures
Post by: Noopy on March 31, 2021, 04:09:19 am
Sounds plausible!  :-+ :)

I didn´t realize the higher operation temperature in the datasheet but I realized that the mold was a little different.  :-/O :-+
Title: Re: Transistors - die pictures
Post by: Gyro on March 31, 2021, 09:09:28 am
Yes, I did wonder if you had found the packaging different / harder to remove.  :)
Title: Re: Transistors - die pictures
Post by: Noopy on March 31, 2021, 06:27:34 pm
Yes, I did wonder if you had found the packaging different / harder to remove.  :)

Epoxy is a little more brittle after the baking process.
The silicone is more like a little too hard rubber but you can still "crumble" the die out of the residues.  :-/O ;D
Title: Re: Transistors - die pictures
Post by: David Hess on April 01, 2021, 01:58:03 am
I think you may find that the 'E' stands for E-line.  ;) This family dates back to the Ferranti E-Line series.

Is that the same as the E-line transistors from Zetex, now Diodes Incorporated?

Quote
They use a Silicone rather than Epoxy packaging material, allowing higher junction temperatures and dissipations than TO92. They were used a lot in Mil spec equipment.

The E-line transistors from Zetex were known for higher current gain and lower saturation voltage at higher current but not particularly higher power.  I thought Zetex was repurposing old IC production equipment for transistor production which gave them a much smaller feature size to work with.  On Semiconductor and Fairchild and I assume others eventually produced their own versions.

I always hoped that they would extend these designs to the TO-225 and TO-220 packages but this never really happened.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 01, 2021, 04:26:13 am
Yes, Ferranti --> Zetex --> Diodes.

Low-Vce(sat) parts are available in power SMDs up to DPAKs, not sure about D2PAK or leaded (aside from IPAK which almost doesn't count :P ), and up to 8A or so I think.  I don't have any part numbers offhand but I've seen a number of Japanese type numbers that perform very well.  They are (were?) common in CCFL backlights (Baxandall push-pull oscillator).

They also have very good inverted hFE, despite the low Vebo (i.e., asymmetrical junctions).  This is no coincidence, it's a necessary part of getting low Vce(sat).

One thing that's never been made, as far as I know, is a high fT model.  Would be nice to have much faster parts for gate drives I guess; but then, it's hard to make a gate drive that powerful (multiple amperes peak), go much faster than 10ns anyway, and you'll always be limited by stray inductance in that case.  So, shrug.

Ed: oh, I do remember one, https://fscdn.rohm.com/en/products/databook/datasheet-nrnd/discrete/transistor/bipolar/2sc5001.pdf which is since obsolete so YMMV, but you get the idea.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on April 01, 2021, 06:09:09 am
...

I had to correct some misspelling.  :o ;D


The voltage rating of the ZTX312 is interesting:
Vceo = 12V
Vcbo = 35V
That´s quite a difference!
I assume that is because of a very high doping of the emitter (and the base?) which they had to do to get fast switching. What is your opinion?
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 01, 2021, 07:17:23 am
Hmm, wonder if that was gold doped.  Would explain the higher leakage (arguably; leakage at 25°C is low enough it might be a testing limit, but it's also not a very round number?), and the relatively low voltage and switching time.  hFE curves are not provided (steeply reduced hFE at low Ic is a hallmark of such types).

Higher C-B leakage I think is a factor in Vcbo vs. Vceo breakdown, since the leakage is effectively multiplied; I'm not sure what all physics is really at work, as the ratio can be quite significant (as in this case); other times it's much more modest.

The boundary between the two conditions is a kind of avalanche breakdown that generates very high noise, indeed the avalanche multiplication can extend so far that the device saturates in a fraction of a nanosecond, while carrying several amperes in the process.  (Evidently this phenomenon involves two mechanisms: a high-level injection mechanism which crowds out the base doping concentration, effectively causing local punch-through (effectively a C-E short); and subsequent rapid heating, causing formation of a current filament (at high temperatures, intrinsic carriers outnumber dopants, maintaining punch-through).  That perhaps explains why recovery from this mechanism is so slow -- several microseconds at least.)

FWIW, I'd love to see microscopy of a bare die under such operation -- but I'm also afraid that there would be so little light emitted (due to the very low duty cycle, < 0.1% is typical) that it might not show at all.

(The usual setup is: a large pullup resistor to charge the collector, typically 10-100k to +100V or thereabouts; a B-E resistor, typically 4.7k or thereabouts, depending on type; and some kind of load, at least a few pF from C-E but also including an output coupling network like a 50 ohm transmission line or whatever.  100-120V is enough to cause 2N3904 to break down in this way; 2N2369 needs less, 60-80V I think; it even works for high voltage types, but because breakdown occurs as a narrow filament, power transistors are essentially dead weight for this -- a 1500V 10A transistor fails with only a few 100s of pF load, hardly more than a 300V 100mA type can handle.)

Tim
Title: Re: Transistors - die pictures
Post by: exe on April 01, 2021, 07:21:26 am
I have a question. Current western semiconductor companies such as onsemi, vishay, diodes, infineon, nexperia and rohm, do they still produce bjts by themselves, or they just relabel Chinese parts? Asking because bjts are so cheap, how they can make money from them...
Title: Re: Transistors - die pictures
Post by: Noopy on April 01, 2021, 08:36:23 am
Higher C-B leakage I think is a factor in Vcbo vs. Vceo breakdown, since the leakage is effectively multiplied; I'm not sure what all physics is really at work, as the ratio can be quite significant (as in this case); other times it's much more modest.

That sound plausible.
Surprisingly the hfe of the ZTX312 is quite low. I would have suspected more similar breakdown voltages than for example the ZTX108C has to offer: hfe=450-900 and 45V/30V.


FWIW, I'd love to see microscopy of a bare die under such operation -- but I'm also afraid that there would be so little light emitted (due to the very low duty cycle, < 0.1% is typical) that it might not show at all.

(The usual setup is: a large pullup resistor to charge the collector, typically 10-100k to +100V or thereabouts; a B-E resistor, typically 4.7k or thereabouts, depending on type; and some kind of load, at least a few pF from C-E but also including an output coupling network like a 50 ohm transmission line or whatever.  100-120V is enough to cause 2N3904 to break down in this way; 2N2369 needs less, 60-80V I think; it even works for high voltage types, but because breakdown occurs as a narrow filament, power transistors are essentially dead weight for this -- a 1500V 10A transistor fails with only a few 100s of pF load, hardly more than a 300V 100mA type can handle.)

Wouldn´t it be possible to test the CE-breakdown in a constant manner? If we use a low voltage transistor the power dissipation is perhaps low enough to take pictures for some seconds.



I have a question. Current western semiconductor companies such as onsemi, vishay, diodes, infineon, nexperia and rohm, do they still produce bjts by themselves, or they just relabel Chinese parts? Asking because bjts are so cheap, how they can make money from them...

I don´t know. Perhaps they are so cheap because you get 10000000000000000 transistors out of a 300mm wafer.  ;D

Title: Re: Transistors - die pictures
Post by: magic on April 01, 2021, 09:44:00 am
Rohm is very much an eastern company ;)

Given that reputable manufacturers are able to provide detailed detailed datasheets, and that occasionally there are differences in typical characteristics like hFE vs Ic, it seems they still design and control the manufacture of their products. Which exact Asian country the trannies are fabbed and packaged in you could ask your supplier; the country of origin is often given.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 01, 2021, 10:57:52 am
Wouldn´t it be possible to test the CE-breakdown in a constant manner? If we use a low voltage transistor the power dissipation is perhaps low enough to take pictures for some seconds.

Yes, it can be done at some mA -- but I wonder if the result is different in "simmering" versus "switching" operation.

Might be even more interesting in infrared, or far IR for that matter -- good luck getting a lens tight enough though, or enough framerate to see more than a blob of spread-out heat anyway?

(I know semi mfgs have tools to do this sort of thing -- IR microscopes to inspect fabbed dies, from the back side even, as silicon is transparent in longer wavelengths.  Not enough resolution to see individual transistors of course, but enough to have an idea where a problem might be.  Those would probably be able to resolve something... the question then is, can anything cheaper than a million dollars do the same? :P )

Tim
Title: Re: Transistors - die pictures
Post by: David Hess on April 01, 2021, 06:19:42 pm
Wouldn´t it be possible to test the CE-breakdown in a constant manner? If we use a low voltage transistor the power dissipation is perhaps low enough to take pictures for some seconds.

You can, but at low current density, non-uniformity in the junction means that only a small part of the entire junction is likely to break down and be visible.  Breakdown at a much higher current density will show the entire junction, but will quickly overheat the junction unless the time is limited.

Parts intended for avalanche operation, like avalanche rectifiers, have special processing to make the junction more uniform preventing hot spots which would destroy them at lower current.
Title: Re: Transistors - die pictures
Post by: Noopy on April 01, 2021, 08:26:28 pm
Well highspeed IR microscopy is a little to much for my equipment!  ;D

I will try some more breakdown pictures as soon as I have a transistor which fits to this experiments.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on April 03, 2021, 03:46:14 am
(https://www.richis-lab.de/images/Transistoren/79x01.jpg)

KT808, a russian power transistor built by Iskra: 130V, 10A, 60W, 2MHz


(https://www.richis-lab.de/images/Transistoren/79x03.jpg)

There is some potting on the die.


(https://www.richis-lab.de/images/Transistoren/79x06.jpg)

Here we see the MESA trench.


(https://www.richis-lab.de/images/Transistoren/79x07.jpg)

There is a scratch probably caused by a testing probe.
It seems  like the die is protected with polyimid.


(https://www.richis-lab.de/images/Transistoren/79x08.jpg)

Hm, there are metal flakes under the potting.


(https://www.richis-lab.de/images/Transistoren/79x09.jpg)

The avalanche breakdown light of the base emitter junction is quite uneven. (-6,5V / 0,1A)


(https://www.richis-lab.de/images/Transistoren/79x10.jpg)

1A, still uneven.



(https://www.richis-lab.de/images/Transistoren/80x01.jpg)

And one more KT808. It´s an older one.


(https://www.richis-lab.de/images/Transistoren/80x03.jpg)

There are no grooves in the heatspreader that can drain tin.


(https://www.richis-lab.de/images/Transistoren/80x04.jpg)

The bondpads are welded on the side of the connector pin.


(https://www.richis-lab.de/images/Transistoren/80x05.jpg)

There is no yellow protection layer on this transistor.
Quite extreme welding on the die...


(https://www.richis-lab.de/images/Transistoren/80x06.jpg)

MESA


(https://www.richis-lab.de/images/Transistoren/80x07.jpg)

Not really clean...  :o


(https://www.richis-lab.de/images/Transistoren/80x08.jpg)

Lights on!  8)


(https://www.richis-lab.de/images/Transistoren/80x09.jpg)

(https://www.richis-lab.de/images/Transistoren/80x10.jpg)

Even more uneven at -7V/0,1A


(https://www.richis-lab.de/images/Transistoren/80x12.jpg)

2A


https://www.richis-lab.de/Bipolar48.htm (https://www.richis-lab.de/Bipolar48.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 09, 2021, 06:42:58 pm
(https://www.richis-lab.de/images/Transistoren/82x01.jpg)

BUX42
250V, 12A / 15Ap, 8MHz, 120W


(https://www.richis-lab.de/images/Transistoren/82x02.jpg)

(https://www.richis-lab.de/images/Transistoren/82x13.jpg)

A nice transistor.  :-+
Perhaps the C is kind of a binning?
You can barely see the tin of the die attach.


(https://www.richis-lab.de/images/Transistoren/82x14.jpg)

It seems like the tin was quite runny. It flowed a long way inside the trenches on the heatspreader.
The tin layer between the die and the heatspreader is as thin as possible to get best heat conduction.


(https://www.richis-lab.de/images/Transistoren/82x03.jpg)

(https://www.richis-lab.de/images/Transistoren/82x04.jpg)

There is some distance between the emitter contact and the base-emitter-junction. It is a wide-emitter narrow-contact design which ensures equal current distribution.
Interesting: The base metal doesn´t contact the base area on the left edge of the die.


(https://www.richis-lab.de/images/Transistoren/82x05.jpg)

118, perhaps the name of the design.


(https://www.richis-lab.de/images/Transistoren/82x06.jpg)

(https://www.richis-lab.de/images/Transistoren/82x07.jpg)

Lights on!  8) ...at -15V.


(https://www.richis-lab.de/images/Transistoren/82x08.jpg)

20mA


(https://www.richis-lab.de/images/Transistoren/82x09.jpg)

100mA


(https://www.richis-lab.de/images/Transistoren/82x10.jpg)

200mA
Only the junction above the base contacts is glowing!  :o


(https://www.richis-lab.de/images/Transistoren/82x11.jpg)

500mA


(https://www.richis-lab.de/images/Transistoren/82x12.jpg)

1A
At higher currents the the other side of the base comes into play.
But you can clearly see that there is no base contact on the left side. The base resistance is higher at this edge and the current crowds in the rest of the die.


https://www.richis-lab.de/Bipolar50.htm (https://www.richis-lab.de/Bipolar50.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on April 09, 2021, 09:02:57 pm

Some amazing pictures there, @Noopy, have you got some new equipment or techniques you are playing with?  Or do you just keep getting better? :D
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 09, 2021, 09:48:35 pm
Oh wow weird, is that... two, three thicknesses of metallization?

I've always wondered if they do things with metallization thickness but never saw much evidence for it (also, it's extra masks, why bother..?), sure looks like they did that here though.  Would the thinner first layer (particularly for the emitter) serve as ballasting?

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on April 10, 2021, 03:23:07 am
Some amazing pictures there, @Noopy, have you got some new equipment or techniques you are playing with?  Or do you just keep getting better? :D

Actually I´m doing experiments with the Canon MP-E 65mm f/2.8 1-5x but most of the improvement is due to experience and patience.  8)
And sometimes I´m more lucky with my pictures.  ::)


Oh wow weird, is that... two, three thicknesses of metallization?

I've always wondered if they do things with metallization thickness but never saw much evidence for it (also, it's extra masks, why bother..?), sure looks like they did that here though.  Would the thinner first layer (particularly for the emitter) serve as ballasting?

I don´t think there is more than one metal layer. The metal layer looks quite different but I´m pretty sure that is just due to the contact areas and the different heights of the underlaying layer.
The emitter contact for example is the wide-emitter narrow-contact design.
Title: Re: Transistors - die pictures
Post by: magic on April 10, 2021, 06:22:38 am
patience
aka focus stacking :P
Title: Re: Transistors - die pictures
Post by: Noopy on April 10, 2021, 06:41:39 am
patience
aka focus stacking :P

Yes:


(https://www.richis-lab.de/temp/focus.jpg)

(https://www.richis-lab.de/images/Transistoren/82x05.jpg)

37 pictures / 1GB for this one...

 :-/O 8)
Title: Re: Transistors - die pictures
Post by: SilverSolder on April 10, 2021, 12:23:35 pm

Are you using Photoshop for the focus stacking?
Title: Re: Transistors - die pictures
Post by: Noopy on April 10, 2021, 01:45:51 pm
I use Photoshop but for focus stacking I use Helicon Focus: https://www.heliconsoft.com/heliconsoft-products/helicon-focus/ (https://www.heliconsoft.com/heliconsoft-products/helicon-focus/)
Works fine.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on April 15, 2021, 06:20:43 pm
(https://www.richis-lab.de/images/Transistoren/83x01.jpg)

The Motorola ENI-1B seems to be a special transistor for the RF amp manufacturer ENI. It was found in a plasma generator but I can´t tell you more.  :-//
Perhaps Motorola did some binning. Perhaps they just gave it a new name.  :-//


(https://www.richis-lab.de/images/Transistoren/83x02.jpg)

(https://www.richis-lab.de/images/Transistoren/83x03.jpg)

A nice big transistor with a big heatspreader and a big die.


(https://www.richis-lab.de/images/Transistoren/83x04.jpg)

And a nice bondwire!  :-+ 8)


(https://www.richis-lab.de/images/Transistoren/83x05.jpg)

It´s a MESA-transistor.


(https://www.richis-lab.de/images/Transistoren/83x06.jpg)

There are more structures between base and emitter than you would expect.
We have similar structures in the conterfeit BUX22 (https://www.richis-lab.de/Bipolar09.htm (https://www.richis-lab.de/Bipolar09.htm)), in the conterfeit BUX66 (https://www.richis-lab.de/Bipolar42.htm (https://www.richis-lab.de/Bipolar42.htm)) and in the 3DD15D (https://www.richis-lab.de/Bipolar05.htm (https://www.richis-lab.de/Bipolar05.htm)). I still don´t know why they integrated these structures.  :-//


(https://www.richis-lab.de/images/Transistoren/83x07.jpg)

Base emitter breakdown occurs at -11V and is quite uniform.
20mA


(https://www.richis-lab.de/images/Transistoren/83x08.jpg)

50mA


(https://www.richis-lab.de/images/Transistoren/83x09.jpg)

100mA


(https://www.richis-lab.de/images/Transistoren/83x10.jpg)

200mA


(https://www.richis-lab.de/images/Transistoren/83x11.jpg)

500mA


https://www.richis-lab.de/Bipolar51.htm (https://www.richis-lab.de/Bipolar51.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 21, 2021, 12:07:25 pm
I have added two transistors built by CDIL (Continental Device India Ltd.):


(https://www.richis-lab.de/images/transistoren/84x01.jpg)

CDIL BC550C


(https://www.richis-lab.de/images/transistoren/84x02.jpg)

(https://www.richis-lab.de/images/transistoren/84x03.jpg)

With an edge length of 0,31mm the CDIL BC550C is a little bigger than the Philips BC550C (0,26mm x 0,27mm).


(https://www.richis-lab.de/images/transistoren/84x04.jpg)

Yes, it´s a small transistor.  ;D


https://www.richis-lab.de/Bipolar39.htm (https://www.richis-lab.de/Bipolar39.htm)




(https://www.richis-lab.de/images/transistoren/85x01.jpg)

CDIL BC560C


(https://www.richis-lab.de/images/transistoren/85x02.jpg)

(https://www.richis-lab.de/images/transistoren/85x03.jpg)

Although pnp transistors have often worse specifications than npn transistors the CDIL BC560C has the same edge length as the CDIL BC550C.


(https://www.richis-lab.de/images/transistoren/85x04.jpg)

Yes, also a small transistor.  ;D


https://www.richis-lab.de/Bipolar52.htm (https://www.richis-lab.de/Bipolar52.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on April 21, 2021, 01:19:12 pm
Although pnp transistors have often worse specifications than npn transistors the CDIL BC560C has the same edge length as the CDIL BC550C.

Yeah, I wonder about that, according to datasheets, their collector-base capacitances are identical. Their die geometries seem to be the same or very similar. Perhaps, they tried to make matching devices? If so, they succeeded. Or, may be, N-devices are only smaller when it comes to fets?
Title: Re: Transistors - die pictures
Post by: Noopy on April 21, 2021, 04:15:19 pm
Although pnp transistors have often worse specifications than npn transistors the CDIL BC560C has the same edge length as the CDIL BC550C.

Yeah, I wonder about that, according to datasheets, their collector-base capacitances are identical. Their die geometries seem to be the same or very similar. Perhaps, they tried to make matching devices? If so, they succeeded. Or, may be, N-devices are only smaller when it comes to fets?


Philips BC550 and BC560 were different in size...  :-/O

Edit: It looks like the BC560 has a smaller "base contact frame" and so more active area than the BC550.
Title: Re: Transistors - die pictures
Post by: Noopy on April 28, 2021, 08:11:13 am
(https://www.richis-lab.de/images/Transistoren/86x01.jpg)

OC811, the first junction transistor built in the GDR.
20V / 15mA


(https://www.richis-lab.de/images/Transistoren/86x03.jpg)

(https://www.richis-lab.de/images/Transistoren/86x04.jpg)

(https://www.richis-lab.de/images/Transistoren/86x05.jpg)

The usual construction...


(https://www.richis-lab.de/images/Transistoren/86x10.jpg)

(https://www.richis-lab.de/images/Transistoren/86x07.jpg)

(https://www.richis-lab.de/images/Transistoren/86x06.jpg)

(https://www.richis-lab.de/images/Transistoren/86x11.jpg)

In some of the OC811 it seems like they had problems with the production quality.  :o


https://www.richis-lab.de/Bipolar53.htm (https://www.richis-lab.de/Bipolar53.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on April 28, 2021, 11:18:57 am
Ah, hand soldering, good ol' days :). In the USSR we had a rumor that only women were hired to do the final assembly (i.e., attaching bond wires). Also, I was told they were not allowed to open windows in the facility as that would half the yield due to impurities in the air and drafts. Do you know any anecdotes about semiconductor production back in the day?
Title: Re: Transistors - die pictures
Post by: Noopy on April 28, 2021, 02:27:59 pm
I have heard of erratic low yields in one of the old american semiconductor companies. Most of the time everything was perfect and sometimes the yield was really low. It took them some time to realise the root cause was a farmer who from time to time sprayed herbicides. His field was located besides the factory. The chemicals made their way through the air supply and killed the devices.  :-BROKE
Title: Re: Transistors - die pictures
Post by: Noopy on May 04, 2021, 04:21:57 am
(https://www.richis-lab.de/images/Transistoren/87x01.jpg)

ON Semiconductor BC546B. The high voltage type of the BC5xx series (65V).
...well, at least it should be a ON Semiconductor BC546B. You can´t be 100% sure. These small packages and dies give you almost no hint who is the manufacturer.
The pins are not covered with tin completely. That´s seems a little odd to me.  ???


(https://www.richis-lab.de/images/Transistoren/87x02.jpg)

(https://www.richis-lab.de/images/Transistoren/87x03.jpg)

The die is 0,33mm x 0,33mm.



(https://www.richis-lab.de/images/Transistoren/88x01.jpg)

ON Semiconductor BC546C. Index C gives you the highest hfe (420 - 800).


(https://www.richis-lab.de/images/Transistoren/88x02.jpg)

(https://www.richis-lab.de/images/Transistoren/88x03.jpg)

Unsurprisingly the BC546B uses the same die as the BC546C.


https://www.richis-lab.de/Bipolar54.htm (https://www.richis-lab.de/Bipolar54.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 06, 2021, 03:25:43 am
(https://www.richis-lab.de/images/Transistoren/89x01.jpg)

ON Semiconductor BC556B, the PNP type beside the B546.


(https://www.richis-lab.de/images/Transistoren/89x02.jpg)

(https://www.richis-lab.de/images/Transistoren/89x03.jpg)

Same size, same structure.  :-/O


https://www.richis-lab.de/Bipolar55.htm (https://www.richis-lab.de/Bipolar55.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 08, 2021, 04:00:28 am
(https://www.richis-lab.de/images/Transistoren/82x01.jpg)

I have put some more information about the BUX42 here: https://www.eevblog.com/forum/projects/decapping-and-chip-documentation-howto/msg3565360/#msg3565360 (https://www.eevblog.com/forum/projects/decapping-and-chip-documentation-howto/msg3565360/#msg3565360)
Title: Re: Transistors - die pictures
Post by: Noopy on May 21, 2021, 03:14:42 am
(https://www.richis-lab.de/images/Transistoren/71x01.jpg)

...

(https://www.richis-lab.de/images/Transistoren/71x07.jpg)

The structure is interesting. The left brown area is the p-doped emitter. The following green are is the n-doped base. In the next pictures we will see that this is the base-emitter-junction.
Before the base contact there is a small brown p-doped layer certainly above the base area. Why that? Looks like a pinch resistor to increase the base resistance. But why would they increase the base resistance? Perhaps the resistance is equalising the electric stress on the transistor area?  :-//


(https://www.richis-lab.de/images/Transistoren/71x08.jpg)

That´s the base emitter junction!  8)
(13,5V / 20mA)

...



(https://www.richis-lab.de/images/Transistoren/71x12.jpg)

(https://www.richis-lab.de/images/Transistoren/71x13.jpg)

Do you remember the counterfeit BUX66?
If we remove the metal layer we get a better look at the strange structure around the base area. As already described in the n-type base area (cyan) there is a p-type ring (light green) just behind the pn-junction. I still don´t know why.  :-//


https://www.richis-lab.de/Bipolar42.htm (https://www.richis-lab.de/Bipolar42.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: magic on May 21, 2021, 08:45:50 am
It seems a theoretical possibility that uniformly distributed base resistance reduces formation of current hot spots and improves SOA.
A local increase in current increases voltage loss across Rb and reduces Vbe.
Title: Re: Transistors - die pictures
Post by: Noopy on May 23, 2021, 04:11:34 am
It seems a theoretical possibility that uniformly distributed base resistance reduces formation of current hot spots and improves SOA.
A local increase in current increases voltage loss across Rb and reduces Vbe.

Sounds plausible.  :-+


(https://www.richis-lab.de/images/Transistoren/90x01.jpg)

(https://www.richis-lab.de/images/Transistoren/90x02.jpg)

Today we will take a look into a RCA 2N3375.
The 2N3375 is very similar to the 2N3553 (https://www.richis-lab.de/Bipolar22.htm (https://www.richis-lab.de/Bipolar22.htm)) but can conduct more current and dissipate more heat  (0,5A/1,5A vs. 0,33A/1A and 11,6W vs. 7W).


(https://www.richis-lab.de/images/Transistoren/90x03.jpg)

The pins are embedded in a pink ceramic.


(https://www.richis-lab.de/images/Transistoren/90x04.jpg)

You have to grind carefully because the 2N3375 contains BeO.  :-/O


(https://www.richis-lab.de/images/Transistoren/90x06.jpg)

The pins were soldered to the ceramic which carries the transistor.


(https://www.richis-lab.de/images/Transistoren/90x05.jpg)

Here we have the BeO which isolates the transistor from the package.
The flat makes it easier to align the ceramic.


(https://www.richis-lab.de/images/Transistoren/90x07.jpg)

The die is the same as the die in the 2N3553. The higher power capability of the 2N3375 is just caused by the different package.
Here we have only one bondwire but the bondwires are welded to the carrier three times.
Perhaps the 2N3632 (1A/3A, 23W) which is on the same datasheet contains two of these dies. The datasheet states two times the base-collector-capacity...


(https://www.richis-lab.de/images/Transistoren/90x09.jpg)

Gold solder.  8)


(https://www.richis-lab.de/images/Transistoren/90x08.jpg)

(https://www.richis-lab.de/images/Transistoren/90x10.jpg)

More about the multi emitter design can be found here:
https://www.richis-lab.de/Bipolar22.htm (https://www.richis-lab.de/Bipolar22.htm)
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3286140/#msg3286140 (https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3286140/#msg3286140)


https://www.richis-lab.de/Bipolar56.htm (https://www.richis-lab.de/Bipolar56.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 27, 2021, 10:42:42 am
(https://www.richis-lab.de/images/Transistoren/91x01.jpg)

That´s a dead Motorola MJ802 (90V/30A/2MHz/200W).


(https://www.richis-lab.de/images/Transistoren/91x02.jpg)

(https://www.richis-lab.de/images/Transistoren/91x03.jpg)

A big die and a big heatspreader as we would expect.
They used different bondwire diameters for emitter and base.
And yes, it´s dead.  ;D


(https://www.richis-lab.de/images/Transistoren/91x04.jpg)

We can spot four dots due to the testing in the production line.


(https://www.richis-lab.de/images/Transistoren/91x05.jpg)

It´s a MESA transistor with a trench at the edges.


(https://www.richis-lab.de/images/Transistoren/91x06.jpg)

(https://www.richis-lab.de/images/Transistoren/91x07.jpg)

Now that looks bad. There is a lot of molten metal.


(https://www.richis-lab.de/images/Transistoren/91x08.jpg)

After removing the bondwire we can see the whole mess. In the upper area there is a discoloration over the pn-junction like we have seen it in the 2N2222 I killed (https://www.richis-lab.de/Bipolar04.htm (https://www.richis-lab.de/Bipolar04.htm)). The first failure must have occurred in this area where most of the metal is molten. Some of the metal accumulated right of the bondwire. The die is cracked.  :o


(https://www.richis-lab.de/images/Transistoren/91x09.jpg)

(https://www.richis-lab.de/images/Transistoren/91x11.jpg)

(https://www.richis-lab.de/images/Transistoren/91x10.jpg)

The cracks go all the way down to the heatspreader.
The molten trench is quite deep. Normally the metal layer isn´t that deep. I assume in this small area some of the silicon is molten. Silicon needs 1400°C to melt but with a lot of energy in this small area it should be possible.


(https://www.richis-lab.de/images/Transistoren/91x12.jpg)

I tried to remove the metal layer to see more details of the failed structures but the die fell apart...


https://www.richis-lab.de/Bipolar57.htm (https://www.richis-lab.de/Bipolar57.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 27, 2021, 01:02:42 pm
Aluminum depresses the melting point of silicon, although it does seem suspicious that there'd be enough to do that.  Alternate explanation might be arc flash, and the aluminum carried more current, preferentially heating those areas.  Maybe both!

Ed: If some of the bond wire melted/sprayed into it, that would definitely be enough.  It's not clear from the side view how much if any did; there's a spot on the wire but I can't tell if it's a cavity and I'm seeing through it, or it's just marked by metal vapor.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on May 27, 2021, 04:18:34 pm
That are some interesting thoughts.  :-+

I didn't see significant damage at the bondwires.
In my view there is just some metal build-up
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 27, 2021, 06:47:56 pm
I have a special fondness for Al-Si alloys as I did some amateur foundry work years ago, along with studying some metallurgy, which I still remember a fair bit of. :)

Al-Si alloys have high strength and low ductility as-cast, and flow into molds better than any other alloy.  (Ductility doesn't help castings, as you can't get any strength into them by mechanical working!  Compare with wrought alloys like 6061, which achieve maximum strength with rolling/drawing/etc. so are only available as plate, bar, extrusion, etc.)

Typical compositions are 8-10% or 22-28% Si, a few % of other elements to improve strength (Mg, Cu, etc.) and balance Al.

The eutectic is around 13%, which freezes suddenly at 576°C so isn't good for casting: metal shrinks on freezing, causing it to suck in from anywhere hotter, leaving voids there; it's better that this happens more gradually, with a "mushy" off-eutectic alloy.

The higher concentration is hypereutectic (literally: past eutectic), so instead of growing primary aluminum dendrites on cooling, it's full of plates of Si crystals floating in a eutectic (fine grained) matrix.  The larger Si crystals make it abrasion resistant, and it's good for hot-forging as well, so is commonly used for engine parts such as pistons and connecting rods.

Needless to say, such crystals are very heavily P-doped. :D I don't know that I've ever seen the resistance probed, that'd be an interesting experiment I suppose... it should be measurably different, but still quite a low resistance over either grain (Si or Al).

Al-Si forms no intermetallic compound, it's a simple binary eutectic system.  Much like Pb-Sn, for a familiar example. ;D  Which, for soldering, we prefer around the eutectic, because shrinkage is avoided by the low molten mass required, and because we want the joint to freeze suddenly.  (SAC305 is a bit past eutectic, so tends to leave a rough surface as crystals have enough time to grow to macroscopic size -- hence its tendency to look "cold".  Both silver and copper, by the way, form intermetallics -- brittle compounds that make for a stronger alloy.)


So, at the surface of that poor ex-sistor, it'll be some kind of hyperhypereutectic Al-Si alloy, I should guess.  The melting point will be close to that of pure Si, ~1400°C. :)

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on May 27, 2021, 07:15:53 pm
Hey, we have a Al-Si-Expert here.  :-+

Now it would be interesting how high the temperature on such a die can go. I assume discharging a big capacitor quite fast in some micrometer^3 will give you a lot of temperature.  >:D
Title: Re: Transistors - die pictures
Post by: dzseki on May 27, 2021, 08:16:27 pm
These are the real transistor die pictures  :palm: (pun intended)

(https://www.richis-lab.de/images/Transistoren/91x01.jpg)

That´s a dead Motorola MJ802 (90V/30A/2MHz/200W).


(https://www.richis-lab.de/images/Transistoren/91x02.jpg)

(https://www.richis-lab.de/images/Transistoren/91x03.jpg)

A big die and a big heatspreader as we would expect.
They used different bondwire diameters for emitter and base.
And yes, it´s dead.  ;D


(https://www.richis-lab.de/images/Transistoren/91x04.jpg)

We can spot four dots due to the testing in the production line.


(https://www.richis-lab.de/images/Transistoren/91x05.jpg)

It´s a MESA
transistor with a trench at the edges.


(https://www.richis-lab.de/images/Transistoren/91x06.jpg)

(https://www.richis-lab.de/images/Transistoren/91x07.jpg)

Now that looks bad. There is a lot of molten metal.


(https://www.richis-lab.de/images/Transistoren/91x08.jpg)

After removing the bondwire we can see the whole mess. In the upper area there is a discoloration over the pn-junction like we have seen it in the 2N2222 I killed (https://www.richis-lab.de/Bipolar04.htm (https://www.richis-lab.de/Bipolar04.htm)). The first failure must have occurred in this area where most of the metal is molten. Some of the metal accumulated right of the bondwire. The die is cracked.  :o


(https://www.richis-lab.de/images/Transistoren/91x09.jpg)

(https://www.richis-lab.de/images/Transistoren/91x11.jpg)

(https://www.richis-lab.de/images/Transistoren/91x10.jpg)

The cracks go all the way down to the heatspreader.
The molten trench is quite deep. Normally the metal layer isn´t that deep. I assume in this small area some of the silicon is molten. Silicon needs 1400°C to melt but with a lot of energy in this small area it should be possible.


(https://www.richis-lab.de/images/Transistoren/91x12.jpg)

I tried to remove the metal layer to see more details of the failed structures but the die fell apart...


https://www.richis-lab.de/Bipolar57.htm (https://www.richis-lab.de/Bipolar57.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 27, 2021, 08:21:18 pm
I've had IGBTs fail, in turn crowbarring an industrial 480V circuit.  That's a few 10s of kA fault current, and it lasts for some milliseconds before the fuses open.  In that time, the bondwires and die surface evaporate into plasma, the buildup in pressure blowing apart the plastic casing like a shotgun shell.  In the next milliseconds, the expanding arc flash erodes anything nearby; the PCB showed erosion and melting of supply and output connections, around solder joints.  (Soldermask is an effective insulator at these voltages -- or ablatively under the heat?)

And that was with the smaller SOT-227 modules.  The bigger bus-bar mounted kind tend to launch shrapnel when this happens.  Installing guards is recommended, or operating with the equipment closed up. :)

Likely the above example could've happened in an audio or servo driver, just from electrolytic capacitor discharge.  There's really not that much material there, and an arc delivers heat quite efficiently.  Once the bondwire pops off, the rest is history. :-+

Tim
Title: Re: Transistors - die pictures
Post by: capt bullshot on May 27, 2021, 08:30:45 pm

And that was with the smaller SOT-227 modules.  The bigger bus-bar mounted kind tend to launch shrapnel when this happens.  Installing guards is recommended, or operating with the equipment closed up. :)


This is why most larger IGBT modules are gel filled. The gel absorbs the energy quite efficiently and doesn't create shrapnels.

(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1222725;image)
(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1222727;image)
(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1222729;image)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 27, 2021, 08:40:47 pm
This is why most larger IGBT modules are gel filled. The gel absorbs the energy quite efficiently and doesn't create shrapnels.

Yeah, that helps -- the difference is whether enough energy was released to blast the cover off it (and I suppose, launch bits of goo).  Arc flash is serious business. :o

Basically the difference between a semiconductor fuse right at the device*, versus at the mains inlet (or any fuse type), is how much shrapnel is produced. ;D

*Not that you'd do this on a switching inverter, but upstream of minimal value bypass caps, perhaps.

Tim
Title: Re: Transistors - die pictures
Post by: capt bullshot on May 27, 2021, 08:47:25 pm
This is why most larger IGBT modules are gel filled. The gel absorbs the energy quite efficiently and doesn't create shrapnels.

Yeah, that helps -- the difference is whether enough energy was released to blast the cover off it (and I suppose, launch bits of goo).  Arc flash is serious business. :o

Basically the difference between a semiconductor fuse right at the device*, versus at the mains inlet (or any fuse type), is how much shrapnel is produced. ;D

*Not that you'd do this on a switching inverter, but upstream of minimal value bypass caps, perhaps.

Tim

None of these had semiconductor fuses installed, just the usual line fuses, and the usual DC link capacitors ...
I've seen the aftermath of bigger booms than these, but the covers weren't blasted off, and the goo stays in place. Plasma and / or arcs can escape and leave a lot of blackened stuff, but no flying parts around from these modules. I've seen other stuff (like AC input bridge rectifiers, electrolytic DC link capacitors) explode more violently.

Yes, this stuff gets blown intentionally as part of product safety testing.

Title: Re: Transistors - die pictures
Post by: David Hess on May 27, 2021, 11:47:53 pm
Yeah, that helps -- the difference is whether enough energy was released to blast the cover off it (and I suppose, launch bits of goo).

For the record, the plastic bits from plastic encapsulation will puncture skin and stick in you.  A face shield would not be out of line when doing that sort of development work.
Title: Re: Transistors - die pictures
Post by: David Hess on May 27, 2021, 11:50:51 pm
That´s a dead Motorola MJ802 (90V/30A/2MHz/200W).

I have a parts drawer full of good ones, and some of the complementary parts.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 27, 2021, 11:54:04 pm
None of these had semiconductor fuses installed, just the usual line fuses, and the usual DC link capacitors ...
I've seen the aftermath of bigger booms than these, but the covers weren't blasted off, and the goo stays in place. Plasma and / or arcs can escape and leave a lot of blackened stuff, but no flying parts around from these modules. I've seen other stuff (like AC input bridge rectifiers, electrolytic DC link capacitors) explode more violently.

Yes, this stuff gets blown intentionally as part of product safety testing.

Hmm, lucky!

Oh, also, that's one of those with the snap-on cover with some holes/slots in it, right?  They may vent well enough to avoid utter explosion.  That's no guarantee of course, just a matter of scale -- put enough power into anything, and all that.

Those are, usually smaller in size I think?  Maybe they're making bigger ones now, but I don't recall much beyond 1200V/250-300A as of about a decade ago.  The bigger ones usually have a rigid cover on top, which doesn't have any obvious venting paths as far as I can recall.  (The big ones we were using, were full bridge 1200V/600A I think.)

And the "next size up" bridge rectifier modules, are made the same way I think, not fully potted but probably using some goo or something, and a rigid shell?  Don't think I've seen any with the snap cover like those low profile IGBT modules anyway.

Tim
Title: Re: Transistors - die pictures
Post by: capt bullshot on May 28, 2021, 05:45:36 am
Yes, the large one had a snap-on cover. The other ones had covers with no holes. Anyway,  a cracked cover (but still in one piece) has been seen, normally the module stays in one piece. Larger ones aren't that flat profile anymore, but still gel filled construction and no hard potting.

Rectifiers and SCR modules I've seen are of different construction, they use disc SCR / diodes, pressure contacts, large conductors and hard enclosure material  These hard packaged ones break into pieces and crumbles, as they are buried deep within the complete unit while testing, there's not a big chance of shrapnel flying around. You'd still use adequate protection for your personal safety.
SCR and diodes in gel filled packages exist, usually that flat package. These have no large holes or covers to to vent, but don't explode. For smaller sizes, one can get flat profile modules with input rectifier, output bridge and chopper transistor in one package.

Older bridge rectifiers had hard packaging and potting, these exploded quite nicely ;)
Title: Re: Transistors - die pictures
Post by: Noopy on May 31, 2021, 06:45:09 pm
(https://www.richis-lab.de/images/Transistoren/92x01.jpg)

Clevite 2N257, a germanium power transistor: 35V / 4A


(https://www.richis-lab.de/images/Transistoren/92x02.jpg)

Some drying agent.


(https://www.richis-lab.de/images/Transistoren/92x03.jpg)

(https://www.richis-lab.de/images/Transistoren/92x05.jpg)

Now that are a interesting contact electrodes. There had been one single element that was cut into base and emitter in two places.


(https://www.richis-lab.de/images/Transistoren/92x04.jpg)

The germanium plate is connected to a disk that is soldered to the base electrode.


(https://www.richis-lab.de/images/Transistoren/92x06.jpg)

Here we have the emitter contact on the germanium disk.


(https://www.richis-lab.de/images/Transistoren/92x07.jpg)

After removing the residues of the lid we can see the collector part of the transistor.


https://www.richis-lab.de/Bipolar58.htm (https://www.richis-lab.de/Bipolar58.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 06, 2021, 04:44:54 am
(https://www.richis-lab.de/images/transistoren/93x01.jpg)

STP3NB100FP, another Power-MOSFET (1000V, 3A, 5,3 \$\Omega\$).


(https://www.richis-lab.de/images/transistoren/93x02.jpg)

(https://www.richis-lab.de/images/transistoren/93x03.jpg)

The die is 3,9mm x 3,7mm.


(https://www.richis-lab.de/images/transistoren/93x04.jpg)

(https://www.richis-lab.de/images/transistoren/93x05.jpg)

The STP3NB100 doesn´t use the small square transistors we have seen in other power transistors. The datasheet calls it "strip layout".


(https://www.richis-lab.de/images/transistoren/93x06.jpg)

The electrical field steering is mentioned in the datasheet too and looks quite interesting.
Most transistors use toroidal lines. Here we have squares with different size.  :-//


https://www.richis-lab.de/FET15.htm (https://www.richis-lab.de/FET15.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on June 06, 2021, 01:54:39 pm
[...]
Most transistors use toroidal lines. Here we have squares with different size.  :-//
[...]


Perhaps a French design?  French engineers often like to do things different...  (think Citroën)

Title: Re: Transistors - die pictures
Post by: Noopy on June 06, 2021, 03:38:26 pm
[...]
Most transistors use toroidal lines. Here we have squares with different size.  :-//
[...]


Perhaps a French design?  French engineers often like to do things different...  (think Citroën)

Sound reasonable!  :)
Title: Re: Transistors - die pictures
Post by: Noopy on June 10, 2021, 12:40:40 pm
(https://www.richis-lab.de/images/transistoren/94x01.jpg)

(https://www.richis-lab.de/images/transistoren/94x12.jpg)

SU111, a Darlington-Transistor built by Gleichrichterwerk Stahnsdorf.
400V, 10A/15A, 120W


(https://www.richis-lab.de/images/transistoren/94x03.jpg)

Quite a high socket on which the die is placed.
A small bondwire for the base current and a thick bondwire for the emitter current.


(https://www.richis-lab.de/images/transistoren/94x04.jpg)

The silicon is quite easy to remove.


(https://www.richis-lab.de/images/transistoren/94x05.jpg)

The upper part of the die is the driver transistor part. The lower part of the die is the power transistor part.


(https://www.richis-lab.de/images/transistoren/94x06.jpg)

(https://www.richis-lab.de/images/transistoren/94x07.jpg)

It´s a MESA transistor. Etching the trench did quite some damage to the surface nearby.


(https://www.richis-lab.de/images/transistoren/94x08.jpg)

Base-Emitter-junction...


(https://www.richis-lab.de/images/transistoren/94x09.jpg)

(https://www.richis-lab.de/images/transistoren/94x10.jpg)

(https://www.richis-lab.de/images/transistoren/94x11.jpg)

Removing the metal layer gives us some more details.


(https://www.richis-lab.de/images/transistoren/94x13.jpg)

(https://www.richis-lab.de/images/transistoren/94x14.jpg)

In my view the setup looks like this.


(https://www.richis-lab.de/images/transistoren/94x15.jpg)

Current that flows into the base of the driver transistor activates a current flow from its collector to its emitter.
The emitter current of the driver transistor is directed to the base of the power transistor and activates this transistor.
I assume the blue rectangle in the base of the driver transistor throttles the base current so that this base current doesn´t switch the power transistor directly. Not sure about that.  :-//


(https://www.richis-lab.de/images/transistoren/94x16.jpg)

The resistor R1 is part of the base layer. To get the resistor R2 the base layer connects the T2 emitter metal layer through the emitter layer.
Switching the SU111 off the free charges in the driver transistor flow through R1 to the emitter of the power transistor. The free charges of the power transistor take the same way to the emitter.
The "hole" in the emitter layer of the power transistor has a second purpose. It gives you the emitter-collector-diode that you need in half bridge or H-bridge configurations.


https://www.richis-lab.de/Bipolar59.htm (https://www.richis-lab.de/Bipolar59.htm)

 :-+

Title: Re: Transistors - die pictures
Post by: SilverSolder on June 10, 2021, 02:02:04 pm

Interesting, I didn't know that Darlingtons were implemented on a single chip like that...  makes sense, obviously.
Title: Re: Transistors - die pictures
Post by: Noopy on June 10, 2021, 02:13:40 pm

Interesting, I didn't know that Darlingtons were implemented on a single chip like that...  makes sense, obviously.

I have opened a MJ3001. Looks different but quite similar.  ;D Coming soon...  :-/O

Title: Re: Transistors - die pictures
Post by: magic on June 10, 2021, 10:42:18 pm
Interesting, I didn't know that Darlingtons were implemented on a single chip like that...  makes sense, obviously.
Old story, Sidney Darlington had a patent on that.

Quote
8. A signal translating device comprising a body of semi-conductive material having therein a first zone of one conductivity type, a pair of spaced zones of the opposite conductivity type contiguous with said first zone and a pair of zones of said one type each contiguous with a respective one of said first pair of zones, and remote from the other, means electrically connectin one of said first pair of zones to the one of said second pair of zones remote therefrom, and individual electrical connections to said first zone, the other of said first pair of zones and the other of said second pair of zones.
Title: Re: Transistors - die pictures
Post by: Noopy on June 11, 2021, 03:06:11 am
Interesting, I didn't know that Darlingtons were implemented on a single chip like that...  makes sense, obviously.
Old story, Sidney Darlington had a patent on that.

Quote
8. A signal translating device comprising a body of semi-conductive material having therein a first zone of one conductivity type, a pair of spaced zones of the opposite conductivity type contiguous with said first zone and a pair of zones of said one type each contiguous with a respective one of said first pair of zones, and remote from the other, means electrically connectin one of said first pair of zones to the one of said second pair of zones remote therefrom, and individual electrical connections to said first zone, the other of said first pair of zones and the other of said second pair of zones.

But that sounds more like the (Motorola) MJ3001 (coming soon): Two transistors on one die separated except for the collector.
By contrast the SU111 share the base layer.
Title: Re: Transistors - die pictures
Post by: magic on June 11, 2021, 08:50:05 am
Good observation. I wonder if that base-to-base resistor could make this device exempt from Darlington's patent :-DD
Perhaps not, because it had other, more general claims.

BTW, US2663806 was granted in 1953 so it should have expired long, long ago and not be a concern in any remotely modern design.
Title: Re: Transistors - die pictures
Post by: dzseki on June 11, 2021, 09:02:36 am
Good observation. I wonder if that base-to-base resistor could make this device exempt from Darlington's patent :-DD
Perhaps not, because it had other, more general claims.

BTW, US2663806 was granted in 1953 so it should have expired long, long ago and not be a concern in any remotely modern design.

Not that eastern block companies gave much on western patents, eh? :)
Title: Re: Transistors - die pictures
Post by: Noopy on June 12, 2021, 03:35:07 am
(https://www.richis-lab.de/images/transistoren/95x01.jpg)

Now the Darlington MJ3001: 80V, 10A, 150W


(https://www.richis-lab.de/images/transistoren/95x04.jpg)

Nothing special to see but...


(https://www.richis-lab.de/images/transistoren/95x06.jpg)

(https://www.richis-lab.de/images/transistoren/95x07.jpg)

...the die is interesting!  :-+
There are two trenches isolating the driver transistor.


(https://www.richis-lab.de/images/transistoren/95x10.jpg)

Let´s remove the metal layer. The package got dissolved too.  >:D


(https://www.richis-lab.de/images/transistoren/95x11.jpg)

Now we see a little bit more.


(https://www.richis-lab.de/images/transistoren/95x12.jpg)

In the upper right corner we have the driver transistor. The base area in the middle of the area and the emitter like a ring around (above) it.
The metal layer connects the emitter of the driver transistor via a catwalk with the base area of the power transistor.
The power transistor is constructed like other power transistors: A base area with a emitter island above it.

You have to look closely to find the base emitter resistor R1. It is build with the red base area leading from the base area of the driver transistor, under the emitter of the driver transistor, over the catwalk to the base area of the power transistor which is connected to the emitter of the driver transistor over the metal layer.
The green area on the catwalk forms a pinch resistor to get the high resistance (2k).

The base emitter resistor R2 is built with the green emitter material of the power transistor. There is a small short stub in the lower left corner which is enough to get the 50 \$\Omega\$.

The freewheeling diode is integrated underneath the emitter bonding area. There is a opening in the emitter area so the metal layer connects to the base area which gives you the freewheeling diode from the collector to the emitter of the MJ3001.

The MJ3001 is not really built like the transistor described in the patent US2663806. The base areas are still connected.


https://www.richis-lab.de/Bipolar60.htm (https://www.richis-lab.de/Bipolar60.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on June 12, 2021, 06:29:44 am
I see metal layer fully covers R1. Why it doesn't short it?
Title: Re: Transistors - die pictures
Post by: Noopy on June 12, 2021, 06:36:01 am
I see metal layer fully covers R1. Why it doesn't short it?

There is SiO2 all over the place isolating the red/green silicon. The metal layer makes contact where the greyish areas are nowhere else.  :-/O

In the greyish areas the SiO2 is opened and we see the residues of the.contact. Probably it's the rough surface we see.
Title: Re: Transistors - die pictures
Post by: Noopy on June 16, 2021, 03:43:25 am
I have added a new category:
"Thyristors and Variants"
https://www.richis-lab.de/Thyristoren.htm (https://www.richis-lab.de/Thyristoren.htm)
I will continue to post the parts here.


(https://www.richis-lab.de/images/transistoren/96x01.jpg)

General Electric 3N84, a "Thyristortetrode" also known as "Silicon Controlled Switch (SCS)".
It´s a Thyristor with a second gate.


(https://www.richis-lab.de/images/transistoren/96x09.jpg)

A long time ago SCS were used in a lot of special applications like counters and ring memory but even today there is an interesting applications shown in the datasheet of the TISP83121 which is still available. With such a protection circuit you don´t deflect overvoltages (and undervoltages) into your supply like with clamping diodes but to ground. That is often a lot less problematic.


(https://www.richis-lab.de/images/transistoren/96x04.jpg)

The fourth pin is connected to the can.


(https://www.richis-lab.de/images/transistoren/96x05.jpg)

(https://www.richis-lab.de/images/transistoren/96x06.jpg)

The die is 0,5mm x 0,5mm and looks quite similar to the 2N6027 which I have updated too: https://www.richis-lab.de/Bipolar14.htm (https://www.richis-lab.de/Bipolar14.htm)


(https://www.richis-lab.de/images/transistoren/96x07.jpg)

(https://www.richis-lab.de/images/transistoren/96x08.jpg)

Understanding the different areas is no big deal.
The square in the lower right corner seems to be a testpoint for the Cathode-Gate.


https://www.richis-lab.de/Bipolar61.htm (https://www.richis-lab.de/Bipolar61.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on June 16, 2021, 02:13:34 pm
A long time ago SCS were used in a lot of special applications like counters and ring memory but even today there is an interesting applications shown in the datasheet of the TISP83121 which is still available. With such a protection circuit you don´t deflect overvoltages (and undervoltages) into your supply like with clamping diodes but to ground. That is often a lot less problematic.

The same thing can be done with a bipolar transistor to redirect the current into the positive supply into ground instead, but I hardly ever see it done.  I guess the advantage of an SCS is that it latches on during the overload so there is no gate current into the positive supply.

If you did need an SCS now, a pair of bipolar transistors could be used just as with an SCR.
Title: Re: Transistors - die pictures
Post by: mawyatt on June 16, 2021, 03:04:41 pm
Long ago we used 3 SCRs with core die in planes X, Y and Z as high energy detectors. These were used to "crowbar" the main power supplies when a nuclear event was detected. The idea was too quickly discharge the main energy sources in the PS before they had time to damage the main electronics in the system. During an event all the semiconductor PN junctions become forward biased and can damage the chip, this also required a minimum decoupling capacitor to limit the available energy source for the forward biased junctions. We also used large die transistors like 2N3055 as detectors. Early CMOS chips would latch up during an event, remember seeing a very expensive CMOS chip melted because of this. RCA developed a CMOS Silicon on Sapphire (SOS) process especially for radiation-hard use, later others developed Silicon on Insulator (SOI) processes for various reasons including rad hard features. Lots of time and effort went into developing techniques for equipment nuclear survivability, with different levels for different types of equipment. We had an on-site Flash Xray lab to emulate a nuclear event to help with these developments.

Thank goodness we never had to find out if all this rad-hard stuff actually worked :phew:

BTW great images as usual :-+

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on June 16, 2021, 06:36:12 pm
If you did need an SCS now, a pair of bipolar transistors could be used just as with an SCR.

 :-+



Long ago we used 3 SCRs with core die in planes X, Y and Z as high energy detectors. These were used to "crowbar" the main power supplies when a nuclear event was detected. The idea was too quickly discharge the main energy sources in the PS before they had time to damage the main electronics in the system. During an event all the semiconductor PN junctions become forward biased and can damage the chip, this also required a minimum decoupling capacitor to limit the available energy source for the forward biased junctions. We also used large die transistors like 2N3055 as detectors.

Very interesting!  :-+


We had an on-site Flash Xray lab to emulate a nuclear event to help with these developments.

I´m sure that was an interesting lab!  ;D


BTW great images as usual :-+

Thanks!  8)

Title: Re: Transistors - die pictures
Post by: Noopy on June 19, 2021, 06:24:12 pm
(https://www.richis-lab.de/images/transistoren/95x01.jpg)
...


I have a more recent Motorola MJ3001:


(https://www.richis-lab.de/images/transistoren/97x01.jpg)

(https://www.richis-lab.de/images/transistoren/97x02.jpg)

(https://www.richis-lab.de/images/transistoren/97x03.jpg)

Now that is the kind of package and heatspreader we expect in more recent transistors.


(https://www.richis-lab.de/images/transistoren/97x05.jpg)

(https://www.richis-lab.de/images/transistoren/97x04.jpg)

The design is the same as in the older one but the die doesn´t look very good.  ???
It´s kind of dirty and in the upper left corner there is a hole in the metal layer.


https://www.richis-lab.de/Bipolar60.htm (https://www.richis-lab.de/Bipolar60.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 22, 2021, 03:45:01 am
(https://richis-lab.de/images/transistoren/98x01.jpg)

TIC236, a Triac built by Texas Instruments.
There are eight indices with voltage ratings from 100V to 800V. M stands for 600V.
The TIC236 allows a continuous current of 12A.


(https://richis-lab.de/images/transistoren/98x03.jpg)

(https://richis-lab.de/images/transistoren/98x02.jpg)

In the middle of the die is the gate contact. In the lower area of the die there are two big bondwires contacting the upper main terminal (surge current is 100A!).


(https://richis-lab.de/images/transistoren/98x04.jpg)

A etched trench guarantees clean edges for high voltage ratings.


(https://richis-lab.de/images/transistoren/98x05.jpg)

At the gate contact there are two etched hemispheres.
You can spot the different doping...


(https://richis-lab.de/images/transistoren/98x06.jpg)

Removing the metal layer doesn´t help very much but you can guess the construction.


(https://richis-lab.de/images/transistoren/98x07.jpg)

(https://richis-lab.de/images/transistoren/98x08.jpg)

There are two antiparallel connected thyristors. In the middle the gate with the p- and the n-doped areas can generate free charges in every operating point and fire up the thyristor.
The hemispheres at the gate contact were neccessary so that the n-doping of the gate doesn´t short to the n-doping of the main contact.


https://richis-lab.de/Bipolar62.htm (https://richis-lab.de/Bipolar62.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: mawyatt on June 23, 2021, 12:34:40 am
We had an on-site Flash Xray lab to emulate a nuclear event to help with these developments.

I´m sure that was an interesting lab!  ;D

Thanks!

Yes indeed!! They had an audible alarm system to let everyone know they were about to fire off the Flash Xray or Explosive Decompression test, you didn't want to be around for either :o

Keep those great semiconductor images coming, these are fascinating to view, especially for those of us that worked in this field  :-+

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on June 23, 2021, 03:54:54 am
Keep those great semiconductor images coming, these are fascinating to view, especially for those of us that worked in this field  :-+

I will!  :-+ :)
I still have quite a lot semiconductors: big and small, old and new, complex and simple, known by everyone and very special...  8)

I wonder how long it will take till the shutter of my camera quits.  >:D
I bought a new hard disk for my NAS so memory won´t be a problem the next months.
Title: Re: Transistors - die pictures
Post by: exe on June 23, 2021, 06:15:36 pm
I still have quite a lot semiconductors: big and small, old and new, complex and simple, known by everyone and very special...  8)

I vote for FRED/FERD diodes :)
Title: Re: Transistors - die pictures
Post by: Noopy on June 24, 2021, 03:07:56 am
I still have quite a lot semiconductors: big and small, old and new, complex and simple, known by everyone and very special...  8)

I vote for FRED/FERD diodes :)

Acknowledged!  :)
Title: Re: Transistors - die pictures
Post by: Noopy on June 26, 2021, 07:22:37 pm
Some more pictures of the Motorola MJ3001:


(https://www.richis-lab.de/images/transistoren/97x06.jpg)

Yeah, base emitter breakdown!  ;D
The driver transistor is glowing first because at lower currents (0,03A) the base emitter resistor of the power transistor (50 \$\Omega\$) doesn´t  provide enough voltage to drive the base emitter junction of the power transistor into avalanche breakdown.


(https://www.richis-lab.de/images/transistoren/97x08.jpg)

0,2A


(https://www.richis-lab.de/images/transistoren/97x09.jpg)

At 0,5A there is a first light in the power transistor. Can you locate it?  ;)
Here we have a voltage drop of 26V. Assuming the voltage across the driver transistor is still around 13V the voltage drop across the power transistor is 13V too. It´s plausible that both have the same breakdown voltage. To get 13V with a current of 0,5A the resistor across the base emitter junction has to be around 26 \$\Omega\$ (datasheet says 50 \$\Omega\$).
With a voltage drop of 10V across the whole MJ3001 you can estimate a base emitter resistance across the driver transistor of 7k \$\Omega\$ (datasheet says 2k \$\Omega\$).
Well the exact resistances aren´t important and resistors in semiconductors often own a high tolerance.


(https://www.richis-lab.de/images/transistoren/97x10.jpg)

0,6A, there are quite some "highlights" and darker areas.


(https://www.richis-lab.de/images/transistoren/97x13.jpg)

0,9A, still the light is not very uniform.
Through the base emitter resistor of the power transistor there has to flow a current of 0,5A. For the base emitter junction there are only 0,4A left. 0,4A over a larger area gives a dimmer light than 0,9A through the smaller area of the driver transistor.


(https://www.richis-lab.de/images/transistoren/97x14.jpg)

That´s interesting: The light in the driver transistor is quite wide.
You can see it´s no focus problem because in the corners there are sharp structures.


(https://www.richis-lab.de/images/transistoren/97x15.jpg)

(https://www.richis-lab.de/images/transistoren/97x16.jpg)

The light extends wider into the inner base area than into the outer emitter area. Perhaps that is due to the doping concentrations? The higher doped emitter occupies less of the junction than the lower doped base.


(https://www.richis-lab.de/images/transistoren/97x17.jpg)

(https://www.richis-lab.de/images/transistoren/97x18.jpg)

(https://www.richis-lab.de/images/transistoren/97x19.jpg)

Here we see the small defect that shows first light and consumes current from the nearby areas that stay dark at higher currents.
We have seen a similar defect / effect in one of the BUX22: https://www.richis-lab.de/Bipolar07.htm (https://www.richis-lab.de/Bipolar07.htm)


(https://www.richis-lab.de/images/transistoren/97x20.jpg)

The defect is a point with a diameter of round about 4µm.


Some more pictures here:

https://www.richis-lab.de/Bipolar64.htm (https://www.richis-lab.de/Bipolar64.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on June 26, 2021, 07:40:34 pm

(https://www.richis-lab.de/images/transistoren/97x14.jpg)

That´s interesting: The light in the driver transistor is quite wide.
You can see it´s no focus problem because in the corners there are sharp structures.

Why does the light at the 4 corners located inside of the enclosed area (the 4 corners right near the bonding wire) appears as thick as in the straight lines, while in the rest of the corners the light appears to be thinner?
Title: Re: Transistors - die pictures
Post by: Noopy on June 26, 2021, 07:44:05 pm

(https://www.richis-lab.de/images/transistoren/97x14.jpg)

That´s interesting: The light in the driver transistor is quite wide.
You can see it´s no focus problem because in the corners there are sharp structures.

Why does the light at the 4 corners located inside of the enclosed area (the 4 corners right near the bonding wire) appears as thick as in the straight lines, while in the rest of the corners the light appears to be thinner?

I assume it´s all about current distribution. The concave corners get a lot of current while the convex corners have to glow with less current since a lot of the current disappears on the way across the edges.
Title: Re: Transistors - die pictures
Post by: Noopy on June 30, 2021, 03:20:20 am
(https://www.richis-lab.de/images/transistoren/99x01.jpg)

TIC263, a Triac a little more powerful than the TIC236: 25A / 175A.


(https://www.richis-lab.de/images/transistoren/99x03.jpg)

(https://www.richis-lab.de/images/transistoren/99x02.jpg)

Yes, there is some damage.  :-[
The edge length of the die is 4,3mm. They used three bondwires to connect the upper main terminal.


(https://www.richis-lab.de/images/transistoren/99x04.jpg)

A cleanly etched edge.


(https://www.richis-lab.de/images/transistoren/99x05.jpg)

(https://www.richis-lab.de/images/transistoren/99x06.jpg)

We know these structures.  :-+


https://www.richis-lab.de/Bipolar63.htm (https://www.richis-lab.de/Bipolar63.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Miyuki on June 30, 2021, 05:58:08 pm
Just wondering, do beasts for 100 Amps and more still have the same structure just huge, or are many small in parallel?
Title: Re: Transistors - die pictures
Post by: Noopy on June 30, 2021, 06:05:03 pm
Just wondering, do beasts for 100 Amps and more still have the same structure just huge, or are many small in parallel?

"Normal" big Thyristors are just huge single Thyristors.
GTOs have a special structure at one of the main terminals that prevents current crowding while switching off (the triggered switch-off, not the zero-current switch-off).
Title: Re: Transistors - die pictures
Post by: SeanB on June 30, 2021, 07:41:00 pm
How about unijunction transistors, those are hard to emulate these days as a drop in arrangement.
Title: Re: Transistors - die pictures
Post by: Noopy on June 30, 2021, 07:51:37 pm
Here we had the Programmable Unijunction Transistor 2N6027: https://www.richis-lab.de/Bipolar14.htm (https://www.richis-lab.de/Bipolar14.htm)
It´s a built like a thyristor.

Somewhere in my warehouse I have a "real" unijunction transistor. Sooner or later we will see one in detail.  :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on July 09, 2021, 03:33:34 am
(https://www.richis-lab.de/images/transistoren/a00x01.jpg)

Tesla GD619, one of the more rare Germanium-NPN-Powertransistors. 16V / 1A / 4W / 1MHz


(https://www.richis-lab.de/images/transistoren/a00x02.jpg)

Some drying agent.


(https://www.richis-lab.de/images/transistoren/a00x03.jpg)

In the package there is some greenish coat.


(https://www.richis-lab.de/images/transistoren/a00x05.jpg)

Now that is interesting. It seems there are whiskers in the package. In some situations these thin crystals grow out of some metals.
Unfortunately I cleaned the package after the first pictures and realized the whiskers later. So no pictures in more detail.  :'(


(https://www.richis-lab.de/images/transistoren/a00x04.jpg)

On the other side of the base contact there are thicker crystals.


(https://www.richis-lab.de/images/transistoren/a00x06.jpg)

There is some red potting on the transistor but it looks quite "dirty".



(https://www.richis-lab.de/images/transistoren/a01x01.jpg)

The complementary GD619 owns nearly the same specifications but is a little slower: 0,6MHz Perhaps because of the slower p-type doping?


(https://www.richis-lab.de/images/transistoren/a01x02.jpg)

No green potting in this package. No whiskers.


(https://www.richis-lab.de/images/transistoren/a01x03.jpg)

That looks a lot cleaner than in the GD609. But at the bottom there is some green goo too.


https://www.richis-lab.de/Bipolar65.htm (https://www.richis-lab.de/Bipolar65.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2021, 04:30:51 am
(https://www.richis-lab.de/images/transistoren/a02x01.jpg)

Valvo BTY92, a power transistor isolating up to 100V and conducting up to 50A.


(https://www.richis-lab.de/images/transistoren/a02x02.jpg)

(https://www.richis-lab.de/images/transistoren/a02x05.jpg)

Cathode and gate wiring.


(https://www.richis-lab.de/images/transistoren/a02x06.jpg)

(https://www.richis-lab.de/images/transistoren/a02x08.jpg)

The die is protected with some silicone potting.


(https://www.richis-lab.de/images/transistoren/a02x09.jpg)

The gate bondwire was wetched directly on top of the silicon plate.


(https://www.richis-lab.de/images/transistoren/a02x07.jpg)

The General Electric SCR Manual shows how these thyristors were built.


(https://www.richis-lab.de/images/transistoren/a02x10.jpg)

The die is 14,7mm in diameter and 0,2mm thick.


(https://www.richis-lab.de/images/transistoren/a02x11.jpg)

The surface is quite rough and the die seems to get thinner at the edge.


(https://www.richis-lab.de/images/transistoren/a02x12.jpg)

(https://www.richis-lab.de/images/transistoren/a02x13.jpg)

There is a crack around one quarter of the die. I don´t know whether that was a production problem or a damage that occurred later.


https://www.richis-lab.de/Bipolar66.htm (https://www.richis-lab.de/Bipolar66.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on July 18, 2021, 07:47:13 pm
(https://www.richis-lab.de/images/Transistoren/79x03.jpg)

We had these KT808AM built 1984 and 1986. That was the new design of the KT808.


(https://www.richis-lab.de/images/transistoren/a03x01.jpg)

Here we have a KT808AM built 1982.


(https://www.richis-lab.de/images/transistoren/a03x02.jpg)

(https://www.richis-lab.de/images/transistoren/a03x03.jpg)

In this KT808AM we see the old transistor design.


(https://www.richis-lab.de/images/transistoren/a03x04.jpg)

(https://www.richis-lab.de/images/transistoren/a03x05.jpg)

They had some problems with the bondwires. One of the wires got bent accidentally. While this happened the wire was torn off the die.
There seems to be a thin transparent coating on the die.


(https://www.richis-lab.de/images/transistoren/a03x06.jpg)

The edge length of the die is 5,0mm. It´s significant bigger than the die in the newer KT808 (4,3mm).
It´s no surprise older datasheet state a ft of 2MHz while newer datasheets speak of 8MHz.
At the edges there are blue traces probably marking the area where to saw the wafer.
There is a uncommon MESA structure around the transistor.
The bondwires are soldered to the metal structures.


(https://www.richis-lab.de/images/transistoren/a03x07.jpg)

The structures are quite dirty...  ???


(https://www.richis-lab.de/images/transistoren/a03x15.jpg)

Yeah, lights on!


Some more pictures here:

https://www.richis-lab.de/Bipolar67.htm (https://www.richis-lab.de/Bipolar67.htm)

 :-+
Title: Re: Transistors - die pictures
Post by: Noopy on July 26, 2021, 04:01:45 am
(https://www.richis-lab.de/images/transistoren/a04x01.jpg)

The MJ2501 is the PNP brother of the MJ3001 (https://www.richis-lab.de/Bipolar60.htm (https://www.richis-lab.de/Bipolar60.htm)).


(https://www.richis-lab.de/images/transistoren/a04x02.jpg)

(https://www.richis-lab.de/images/transistoren/a04x03.jpg)

The construction is the same as the construction of the MJ3001.


(https://www.richis-lab.de/images/transistoren/a04x04.jpg)

(https://www.richis-lab.de/images/transistoren/a04x05.jpg)

The die is the same too.



(https://www.richis-lab.de/images/transistoren/a05x01.jpg)

This MJ2501 is a little newer (1979 vs. 1978).


(https://www.richis-lab.de/images/transistoren/a05x02.jpg)

(https://www.richis-lab.de/images/transistoren/a05x03.jpg)

The construction is a little less clean.


(https://www.richis-lab.de/images/transistoren/a05x04.jpg)

And the silicon seems to be a little blurred too.  ???


(https://www.richis-lab.de/images/transistoren/a05x06.jpg)

Some imperfections.


(https://www.richis-lab.de/images/transistoren/a05x07.jpg)

Base-emitter-breakdown occurs at -18V, a little later than in the MJ3001 (-13V).
When both junctions are in "breakdown mode" we see some brighter dots.


(https://www.richis-lab.de/images/transistoren/a05x08.jpg)

(https://www.richis-lab.de/images/transistoren/a05x09.jpg)

The structures don´t look good in detail. But you don´t find a cause for the bright dot.  :-//


https://www.richis-lab.de/Bipolar68.htm (https://www.richis-lab.de/Bipolar68.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on July 28, 2021, 09:32:22 am
(https://www.richis-lab.de/images/transistoren/a06x01.jpg)

2N369, a small germanium transistor: Ucb=30V, Ic=50mA, ft=1,3MHz, P=150mW
Manufacturer: ?


(https://www.richis-lab.de/images/transistoren/a06x02.jpg)

(https://www.richis-lab.de/images/transistoren/a06x03.jpg)

Some white paste probably for better heat removal and corrosion protection.


(https://www.richis-lab.de/images/transistoren/a06x04.jpg)

(https://www.richis-lab.de/images/transistoren/a06x05.jpg)

A nice little alloy transistor.
A thin base and a smaller emitter for better specifications.


(https://www.richis-lab.de/images/transistoren/a06x06.jpg)

Quite massive potting in the base of the package.


(https://www.richis-lab.de/images/transistoren/a06x07.jpg)

(https://www.richis-lab.de/images/transistoren/a06x08.jpg)

 8)


https://www.richis-lab.de/Bipolar69.htm (https://www.richis-lab.de/Bipolar69.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on July 30, 2021, 03:37:04 am
(https://www.richis-lab.de/images/transistoren/a07x01.jpg)

Fairchild BC550C


(https://www.richis-lab.de/images/transistoren/a07x02.jpg)

(https://www.richis-lab.de/images/transistoren/a07x03.jpg)

(https://www.richis-lab.de/images/transistoren/a07x04.jpg)

The edge length ist 0,33mm.



(https://www.richis-lab.de/images/transistoren/a08x01.jpg)

Fairchild BC560C


(https://www.richis-lab.de/images/transistoren/a08x02.jpg)

(https://www.richis-lab.de/images/transistoren/a08x03.jpg)

0,33mm edge length, same as the BC550C. The structures are the same too.


https://www.richis-lab.de/Bipolar39.htm (https://www.richis-lab.de/Bipolar39.htm)
https://www.richis-lab.de/Bipolar52.htm (https://www.richis-lab.de/Bipolar52.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 09, 2021, 08:29:20 pm
(https://www.richis-lab.de/images/transistoren/a09x01.jpg)

(https://www.richis-lab.de/images/transistoren/a09x02.jpg)

(https://www.richis-lab.de/images/transistoren/a09x03.jpg)

KT808AT, the "round variant" of the KT808.
You can bolt it on a heatspreader with an additional plate.


(https://www.richis-lab.de/images/transistoren/a09x05.jpg)

It looks quite similar to the KT808AM we had last time (https://www.richis-lab.de/Bipolar67.htm (https://www.richis-lab.de/Bipolar67.htm)).


(https://www.richis-lab.de/images/transistoren/a09x06.jpg)

A nice clean die.


(https://www.richis-lab.de/images/transistoren/a09x07.jpg)

On the lower edge the silicon is splintered.


(https://www.richis-lab.de/images/transistoren/a09x08.jpg)

A alignment aid?


(https://www.richis-lab.de/images/transistoren/a09x09.jpg)

(https://www.richis-lab.de/images/transistoren/a09x10.jpg)

You can distinguish the emitter and the base area. The distances between the electrodes and the pn-junction varies quite a lot.


And now base emitter breakdown (starting at -7,5V):


(https://www.richis-lab.de/images/transistoren/a09x11.jpg)

20mA


(https://www.richis-lab.de/images/transistoren/a09x13.jpg)

100mA


(https://www.richis-lab.de/images/transistoren/a09x14.jpg)

200mA


(https://www.richis-lab.de/images/transistoren/a09x16.jpg)

1A


https://www.richis-lab.de/Bipolar70.htm (https://www.richis-lab.de/Bipolar70.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on August 11, 2021, 05:08:24 am
I always found something oddly satisfying about those old power transistor packages.
Title: Re: Transistors - die pictures
Post by: Noopy on August 11, 2021, 05:22:36 am
I always found something oddly satisfying about those old power transistor packages.

 :-+
They look more like engineering than the "quantum physics" you need for modern integrated circuits.
(Of course there is a lot of engineering in modern devices but I think you know what I mean.)
Title: Re: Transistors - die pictures
Post by: mawyatt on August 11, 2021, 12:28:55 pm
Remember the T03, TO39, TO18, the stud type rectifiers, and the Fairchild transistors with circular ceramic base with black epoxy on top. When I was a kid repairing guitar amps, Peavy used these Fairchild transistors. Think Fairchild also used this package with some RTL logic.

Fond memories indeed!!

Best,
Title: Re: Transistors - die pictures
Post by: exe on August 11, 2021, 04:09:31 pm
I like the aesthetics of metal packages.
Title: Re: Transistors - die pictures
Post by: David Hess on August 11, 2021, 08:15:34 pm
... and the Fairchild transistors with circular ceramic base with black epoxy on top. When I was a kid repairing guitar amps, Peavy used these Fairchild transistors.

And they came in two sizes.  The ones shown below had black ceramic but some had white ceramic.  I think the TO-92 plastic package eventually won out because it was compatible with automatic insertion.

Quote
Think Fairchild also used this package with some RTL logic.

That was Fairchild "MicroLogic" as seen below in the larger packages from 1968.

http://spingalhistory.blogspot.com/2017/02/fairchild-micrologic-worlds-first-ics.html (http://spingalhistory.blogspot.com/2017/02/fairchild-micrologic-worlds-first-ics.html)
http://semiconductormuseum.com/MuseumStore/MuseumStore_Fairchild_923_Index.htm (http://semiconductormuseum.com/MuseumStore/MuseumStore_Fairchild_923_Index.htm)
Title: Re: Transistors - die pictures
Post by: Noopy on August 21, 2021, 03:32:33 am
(https://www.richis-lab.de/images/transistoren/a10x01.jpg)

(https://www.richis-lab.de/images/transistoren/a10x02.jpg)

The famous BF862.


(https://www.richis-lab.de/images/transistoren/a10x03.jpg)

(https://www.richis-lab.de/images/transistoren/a10x04.jpg)

It´s an genuine one!  ;D
The design is very interesting. Two areas contain a lot of small transistors.


(https://www.richis-lab.de/images/transistoren/a10x05.jpg)

Well, Zeptobar´s pictures are better...
There is a very thin gate grid surrounding the drain and source areas contacted by the metal layer.
There are three round areas without contacts and gate grid. Would be interesting what these round areas do. Do they lower the current density? Do they optimize the manufacturing? Some weird noise reduction?  :-//


https://www.richis-lab.de/FET17.htm (https://www.richis-lab.de/FET17.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Miyuki on August 22, 2021, 05:57:50 pm
(https://www.richis-lab.de/images/transistoren/a10x05.jpg)

Well, Zeptobar´s pictures are better...
There is a very thin gate grid surrounding the drain and source areas contacted by the metal layer.
There are three round areas without contacts and gate grid. Would be interesting what these round areas do. Do they lower the current density? Do they optimize the manufacturing? Some weird noise reduction?  :-//

 :-/O
Do I understand it right. Those tiny electrodes connected to bond pads are D/S and the die itself is Gate?


Title: Re: Transistors - die pictures
Post by: Noopy on August 22, 2021, 06:15:04 pm
(https://www.richis-lab.de/images/transistoren/a10x05.jpg)

Well, Zeptobar´s pictures are better...
There is a very thin gate grid surrounding the drain and source areas contacted by the metal layer.
There are three round areas without contacts and gate grid. Would be interesting what these round areas do. Do they lower the current density? Do they optimize the manufacturing? Some weird noise reduction?  :-//

 :-/O
Do I understand it right. Those tiny electrodes connected to bond pads are D/S and the die itself is Gate?

The tiny contacts contact a lower layer where there are small drain and source rectangles.
The channel is controlled by the substrate (below) and a very thin grid that is integrated around the drain and source rectangles (above). The substrate and the grid are the gate.
Title: Re: Transistors - die pictures
Post by: Noopy on August 22, 2021, 07:23:06 pm
(https://www.richis-lab.de/images/transistoren/a11x01.jpg)

(https://www.richis-lab.de/images/transistoren/a11x02.jpg)

2AW - internet says that´s the BF862 manufactured in China while the 2Ap is manufactured in Hong-Kong. I found no official statement to the 2AW. In the datasheet you just find the 2Ap.
The 2AW was one of the cheapest BF862 I found on Ebay (0,5€ while the 2Ap was 2,74€).
The surface of the package looks a little strange like it was sanded.


(https://www.richis-lab.de/images/transistoren/a11x03.jpg)

(https://www.richis-lab.de/images/transistoren/a11x04.jpg)

Surprise, it´s a counterfeit BF862!  :scared:
I´m sure that transistor does behave very different than a BF862.
There is an unused gate bondpad. Gate potential comes through the substrate.


https://www.richis-lab.de/FET18.htm (https://www.richis-lab.de/FET18.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: magic on August 22, 2021, 07:51:27 pm
The 2AW was one of the cheapest BF862 I found on Ebay (0,5€ while the 2Ap was 2,74€).
The surface of the package looks a little strange like it was sanded.
I'm shocked :-DD

Do I understand it right. Those tiny electrodes connected to bond pads are D/S and the die itself is Gate?
Right. Basic structure shown below (Siliconix, "Designing with Field Effect Transistors"). In BF862 the gate is a grid rather than a single line or multiple lines. It seems that the substrate is typically (always?) connected to the top gate and also participates in pinching the channel.

(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1250524;image)

I wonder if those "holes" in BF862 could be connections between the top grid and the substrate.
Title: Re: Transistors - die pictures
Post by: Noopy on August 23, 2021, 04:41:53 am
I wonder if those "holes" in BF862 could be connections between the top grid and the substrate.

That´s possible...  :-//


Someone told me what transistor we probably have found here:

(https://www.richis-lab.de/images/transistoren/a11x05.jpg)

(National Semiconductor FET Databook 1977)

 :-+
Title: Re: Transistors - die pictures
Post by: Noopy on August 24, 2021, 03:20:50 am
(https://www.richis-lab.de/images/transistoren/a12x01.jpg)

Now let´s take a look into a BF861. It has less forward transfer admittance than the BF862 and was sold in three different bins.
M34 is the old Philips naming.


(https://www.richis-lab.de/images/transistoren/a12x02.jpg)

(https://www.richis-lab.de/images/transistoren/a12x03.jpg)

The edge length is 0,32mm. The structures are similar to the structures of the BF862 but they are bigger. Cgd is bigger than Cgd of the BF862 (2,1-2,7pF vs. 1,9pF).


https://www.richis-lab.de/FET19.htm (https://www.richis-lab.de/FET19.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 28, 2021, 04:09:51 am
(https://www.richis-lab.de/images/transistoren/a13x01.jpg)

(https://www.richis-lab.de/images/transistoren/a13x02.jpg)

(https://www.richis-lab.de/images/transistoren/a13x03.jpg)

(https://www.richis-lab.de/images/transistoren/a13x04.jpg)

(https://www.richis-lab.de/images/transistoren/a13x05.jpg)

Today something special.
The К1HT291Б (K1NT291B) is a dual transistor built by ALFA (Latvia). Because the transistors are integrated on one die they are ideal for differential amplifiers => similar temperatures, similar specifications
The special package was used to develop hybrid circuits (the DAC 32 is an example for a hybrid circuit: https://www.richis-lab.de/DAC03.htm (https://www.richis-lab.de/DAC03.htm)). Over the valve like pins in the bottom glass plate you are able to test the transistors. Then you cut the wires near the pins and solder them into your new hybrid circuit.  :-/O


(https://www.richis-lab.de/images/transistoren/a13x06.jpg)

(https://www.richis-lab.de/images/transistoren/a13x07.jpg)

The bondwires hold the die in place. There is some potting protecting the die and the bonds.


(https://www.richis-lab.de/images/transistoren/a13x09.jpg)

(https://www.richis-lab.de/images/transistoren/a13x08.jpg)

The die was cut out of the wafer quite crude.
In the sawing lines there are test structures to monitor the mask alignment and the manufacturing process.


(https://www.richis-lab.de/images/transistoren/a13x10.jpg)

The two transistors are isolated from each other with frames.
The big bondpad connects the collector. It seems like there is no buried collector connection.
You can see the base area and on the right side you can even spot the small emitter area.


https://www.richis-lab.de/Bipolar71.htm (https://www.richis-lab.de/Bipolar71.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on August 28, 2021, 08:07:32 am
What on Earth is that?!   :o
Title: Re: Transistors - die pictures
Post by: Noopy on August 28, 2021, 10:12:50 am
A special package for a special purpose.  ;D

It absolutely makes sense.
In first place you can test the transistors. Perhaps you even test your whole circuit. Date code is 1972. I´m sure there were a lot of tube sockets around.  :-+
Then you cut the wires and just have to solder them in place without the need of bonding wires.  :-+

Hybrid circuits, a world on its own. In Russia they have built a lot with hybrid circuits.
Title: Re: Transistors - die pictures
Post by: RoGeorge on August 28, 2021, 10:55:23 am
It absolutely makes sense.

(https://www.eevblog.com/forum/projects/transistors-die-pictures/?action=dlattach;attach=1255636;image)
Title: Re: Transistors - die pictures
Post by: Noopy on August 28, 2021, 10:59:34 am
 :-DD

YMMD
Title: Re: Transistors - die pictures
Post by: mawyatt on August 28, 2021, 12:02:11 pm
Nice images!!

Wonder if this is something like Fluke did way back then when they developed a RMS detector utilizing a pair of transistors that were thermally isolated from the case. By isolating the transistor pair, this had low thermal mass. The idea was based upon having a integrated resistor pair (50 ohms I believe) near each transistor, one resistor was driven with the measurement waveform, the other resistor driven from an integrating feedback loop to "balance" the two transistors thru heating the resistor to balance the Vbes. This feedback was the equivalent of the heating effect of the waveform and thus the RMS content.

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on August 28, 2021, 12:14:09 pm
Thanks!  :)

Would be a good solution for a RMS detector.  :-+

The more modern version is the LT1088:
https://richis-lab.de/LT1088.htm (https://richis-lab.de/LT1088.htm)
Title: Re: Transistors - die pictures
Post by: magic on August 28, 2021, 01:13:04 pm
The slightly less obsolete version ;)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 28, 2021, 01:39:43 pm
It's... just fucking floating in space?!  What was it rated for, 10mW? :o

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on August 28, 2021, 01:45:34 pm
15mW  ;D
Title: Re: Transistors - die pictures
Post by: mawyatt on August 28, 2021, 01:55:06 pm
Thanks!  :)

Would be a good solution for a RMS detector.  :-+

The more modern version is the LT1088:
https://richis-lab.de/LT1088.htm (https://richis-lab.de/LT1088.htm)

Think LT copied the idea much later, I recall the Fluke note from ~1970. Fluke even thinned the die to reduce the thermal mass and suspended it with wire bonds just like in your images (why I immediately thought of the Fluke concept). At that time the only effective lab means for a somewhat True RMS measurement was the Calorimetric Wattmeter from HP, the analog techniques employing the transistor exponential characteristics worked OK, but didn't handle high crest factors well. Of course the usual absolute value averaged RMS calibrated method back then was only accurate for pure sinusoidal waveforms, and you had to apply a correction factor for other common waveforms.

Edit: Thinned die was often used for various purposes, recall when we were working with Draper Labs a demo of an 200mm thinned wafer you could see thru!!! Then this wafer was wrapped around a Coke can :wtf:

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on September 01, 2021, 05:31:55 am
(https://www.richis-lab.de/images/transistoren/a14x01.jpg)

Tesla KT110, a fast power thyristor. This one holds 400V ("/400"). Other bins isolate 200V to 750V. Continuous current is 3,2A, peak current is 30A, once 50A. The switch off time is less than 40µs.


(https://www.richis-lab.de/images/transistoren/a14x02.jpg)

We know this red potting Tesla used.
The cathode wire is thicker than the gate wire.  :-+


(https://www.richis-lab.de/images/transistoren/a14x03.jpg)

The wires were soldered to the connector pins... ...but that tin ball doesn´t look good.  :o


(https://www.richis-lab.de/images/transistoren/a14x05.jpg)

(https://www.richis-lab.de/images/transistoren/a14x04.jpg)

The edge length is 2,8mm. The cathode area was flooded with tin for lower resistance.
You can spot a step in color between the gate and the cathode area. The construction is probably similar to the well known thyristor structure that is shown with the ST103: https://www.richis-lab.de/Bipolar13.htm (https://www.richis-lab.de/Bipolar13.htm)


(https://www.richis-lab.de/images/transistoren/a14x06.jpg)

They etched the edges of the die (a funny sentence  ;D) to get a clean gate cathode junction edge.


https://www.richis-lab.de/Bipolar72.htm (https://www.richis-lab.de/Bipolar72.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Miyuki on September 01, 2021, 08:17:08 am
(https://www.richis-lab.de/images/transistoren/a14x03.jpg)

The wires were soldered to the connector pins... ...but that tin ball doesn´t look good.  :o
Oh, just imagine that poor workers soldering wires to this  :phew:
Title: Re: Transistors - die pictures
Post by: Noopy on September 05, 2021, 03:24:56 am
(https://www.richis-lab.de/images/transistoren/a15x01.jpg)

2N3700, a transistor that was produces by a lot of companies. I don´t know which company made this one. There is just 2N3700 on the package.
You can get the 2N3700 still today, you can get it with MIL spec and there is even a radiation hardened 2N3700HR. It seems the 2N3700 was integrated in ballistic missiles.  >:D
Max ratings: 80V, 1A, 1W


(https://www.richis-lab.de/images/transistoren/a15x02.jpg)

(https://www.richis-lab.de/images/transistoren/a15x03.jpg)

With an edge length of 0,68mm the die is quite big for a small signal transistor. The contact structure of the metal layer looks like a power transistor. With that setup ft is just 100MHz.


https://www.richis-lab.de/Bipolar73.htm (https://www.richis-lab.de/Bipolar73.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on September 20, 2021, 06:55:59 pm
(https://www.richis-lab.de/images/transistoren/a16x01.jpg)

KT808BM, the worse KT808 (https://www.richis-lab.de/Bipolar48.htm (https://www.richis-lab.de/Bipolar48.htm)). Vce is just 100V (130V for the KT808A).


(https://www.richis-lab.de/images/transistoren/a16x02.jpg)

(https://www.richis-lab.de/images/transistoren/a16x03.jpg)

The old KT808 design...


(https://www.richis-lab.de/images/transistoren/a16x05.jpg)

(https://www.richis-lab.de/images/transistoren/a16x06.jpg)

(https://www.richis-lab.de/images/transistoren/a16x07.jpg)

Not the cleanest structures but the other KT808 (old design) look similar.


(https://www.richis-lab.de/images/transistoren/a16x08.jpg)

Base emitter breakdown occurs at -7,5V (50mA).


(https://www.richis-lab.de/images/transistoren/a16x13.jpg)

(1A) There is an artefact...


(https://www.richis-lab.de/images/transistoren/a16x09.jpg)

(https://www.richis-lab.de/images/transistoren/a16x10.jpg)

(https://www.richis-lab.de/images/transistoren/a16x11.jpg)

(https://www.richis-lab.de/images/transistoren/a16x12.jpg)

There is a small dot with round about 15µm diameter besides the base emitter border. The light emission shows us that the junction goes around this impurity. Due to the higher field strength the breakdown occurs early at this point.



(https://www.richis-lab.de/images/transistoren/a17x01.jpg)

A second KT808BM with the same date code but the thickness of the base plate is nearly twice that of the first KT808BM: 2,5mm vs. 1,4mm.


(https://www.richis-lab.de/images/transistoren/a17x02.jpg)

(https://www.richis-lab.de/images/transistoren/a17x03.jpg)

(https://www.richis-lab.de/images/transistoren/a17x04.jpg)

Nothing special inside... ...but the die attach looks a bit strange. There is quite a lot of solder around the die.


(https://www.richis-lab.de/images/transistoren/a17x05.jpg)

The die looks a little stressed where the connection wires were soldered.


(https://www.richis-lab.de/images/transistoren/a17x07.jpg)

In breakdown (-8V, 1A) the current distribution is very uneven. Most of the light occurs above the base electrodes.


https://www.richis-lab.de/Bipolar74.htm (https://www.richis-lab.de/Bipolar74.htm)


 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on September 24, 2021, 03:58:03 am
(https://www.richis-lab.de/images/transistoren/a18x01.jpg)

(https://www.richis-lab.de/images/transistoren/a18x02.jpg)

SF137, a small HF transistor built by the Halbleiterwerk Frankfurt Oder.
20V 200mA 300MHz


(https://www.richis-lab.de/images/transistoren/a18x02.gif)

Now that is a big current amplification range!  :o


(https://www.richis-lab.de/images/transistoren/a18x04.jpg)

LM, built in September 1972.


(https://www.richis-lab.de/images/transistoren/a18x05.jpg)

(https://www.richis-lab.de/images/transistoren/a18x06.jpg)

(https://www.richis-lab.de/images/transistoren/a18x07.jpg)

The die is 0,49mm x 0,49mm.
The design is similar to the SS109 (https://www.richis-lab.de/Bipolar01.htm (https://www.richis-lab.de/Bipolar01.htm)).


https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on September 24, 2021, 08:26:55 am
(https://www.richis-lab.de/images/transistoren/a18x06.jpg)

(https://www.richis-lab.de/images/transistoren/a18x07.jpg)



It reminds of the rod and crankshaft from the Steam logo:

(https://1000logos.net/wp-content/uploads/2020/08/Steam-Logo-768x480.jpg)
Photo from:  https://1000logos.net/steam-logo/ (https://1000logos.net/steam-logo/)
Title: Re: Transistors - die pictures
Post by: Noopy on September 24, 2021, 08:45:58 am
It reminds of the rod and crankshaft from the Steam logo:

Indeed!
Opening the next TO-3 I will be afraid of small headcrabs!  :scared: ;D
https://half-life.fandom.com/wiki/Headcrab (https://half-life.fandom.com/wiki/Headcrab)
Title: Re: Transistors - die pictures
Post by: RoGeorge on September 24, 2021, 10:17:33 am
Half-Life was an incredibly good game.   :-+
Googled the year and it was released in 1998.
Title: Re: Transistors - die pictures
Post by: Noopy on September 24, 2021, 10:46:13 am
Half-Life was definitely a highlight!  :-+

I got some insider information about the SF137:
It was the first silicon epitaxial planar transistor built by the HFO (1967).
They introduced these many hfe bins to be able to sell as much transistors as possible. After 1970 they mostly got D and E.
Here we have an updated design because the first one consumed 1mm2 of silicon.
Title: Re: Transistors - die pictures
Post by: Noopy on September 26, 2021, 04:04:40 am
(https://www.richis-lab.de/images/transistoren/a19x01.jpg)

2N2915, an old dual bipolar transistor which was built by a lot of companies. I found the first 2N2915 in a GE transistor manual dating back to 1964. This one was built by Texas Instruments.
There was a family of transistors named 2N1913 - 2N1920 with slightly different specifications. The 2N2915 can isolate 45V, can conduct 30mA and gives you a hfe of 60-240 while the hfe factor of the two transistors is higher than 0,9.


(https://www.richis-lab.de/images/transistoren/a19x02.jpg)

(https://www.richis-lab.de/images/transistoren/a19x03.jpg)

In the package there are two dies placed on a ceramic substrate. That gives you a good thermal coupling while the transistors are electrically isolated.


(https://www.richis-lab.de/images/transistoren/a19x04.jpg)

(https://www.richis-lab.de/images/transistoren/a19x05.jpg)

The die has an edge length of 0,43mm. There are four base contacts. You can see that on one contact there was a test needle some time ago.
I assume the outer metal ring is just for a proper border finalization.


https://www.richis-lab.de/Bipolar76.htm (https://www.richis-lab.de/Bipolar76.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on September 26, 2021, 05:44:34 am
Dual transistors like that were very common as differential pairs until the 741 operational amplifier became popular and economical.
Title: Re: Transistors - die pictures
Post by: Noopy on September 26, 2021, 05:50:28 am
Dual transistors like that were very common as differential pairs until the 741 operational amplifier became popular and economical.

 :-+

I should have mentioned that. The binned and thermally coupled transistors work well in differential stages.
Title: Re: Transistors - die pictures
Post by: bsw_m on September 26, 2021, 11:06:40 pm
A dual low noise differential pair on channel field-effect transistors US006 was used on a V7-54 voltmeter as the input differential pair of the amplifier of the device. In reality, it has an ultra-low leakage current of the gate (according to the documentation, no more than 3pA, according to measurements it is less than 100fA). The actual offset of the amplifier on this micro-assembly (without offset correction) is no more than 30μV.
This micro-assembly was developed and manufactured by MNIPI.
Includes 4 crystals a channel field-effect transistor crystals and a set of resistors, with the possibility of adjustment.
Title: Re: Transistors - die pictures
Post by: bsw_m on September 26, 2021, 11:55:22 pm
A electrometric pair of P-channel MOSFETs.
Designed and manufactured by MNIPI. In production from 1978 to 19??
This pair of transistors was used in electrometers and electrometric amplifiers developed by MNIPI.
An example of devices where these transistors were used are U5-11, V7E-42.
Of interesting, datasheet say that gate leakage current value does not exceed 1fA. The measured actual value of the gate leakage current is approximately 50aA.
Title: Re: Transistors - die pictures
Post by: David Hess on September 27, 2021, 05:39:29 am
Dual transistors like that were very common as differential pairs until the 741 operational amplifier became popular and economical.

I should have mentioned that. The binned and thermally coupled transistors work well in differential stages.

They are not the only ones, but I was thinking of various Tektronix linear regulator designs which changed from dual transistors to 741 and 1458 operational amplifiers sometime between 1981 and 1984.  They used a lot of 2N2918/2N2919s in the form of two 2N2484s in the TO-78 package as differential pairs for the voltage and current error amplifiers.  They had more than three different grades but I do not know what their matching criteria was beyond one being low noise and one being higher voltage.  I assume the offset voltage would have been somewhere between 1.5 and 5 millivolts but maybe they were making their own to get better precision, or were just being cheap.

I do not have any spares or extras, or I could mail one to Noopy to get an idea of what they were doing.
Title: Re: Transistors - die pictures
Post by: David Hess on September 27, 2021, 05:48:11 am
A pair of P-channel MOSFETs.
Designed and manufactured by MNIPI.
This pair of transistors was used in electrometers and electrometric amplifiers developed by MNIPI.
An example of devices where these transistors were used are U5-11, V7E-42.
Of interesting, passport gate leakage current value does not exceed 1fA. The measured actual value of the gate leakage current is approximately 50aA.

How did others get those kinds of parts?  Did they grade 3N series MOSFETs or 2N4351s for gate leakage?
Title: Re: Transistors - die pictures
Post by: bobAk on September 28, 2021, 12:40:48 am
What is 3n mosfet?
Title: Re: Transistors - die pictures
Post by: David Hess on September 28, 2021, 03:24:41 am
What is 3n mosfet?

The original common discrete 4-lead small signal MOSFETs, which are still available, were JEDEC registered with 3N part numbers like 3N163 through 3N166, 3N170, 3N171, 3N190, 3N191, etc.
Title: Re: Transistors - die pictures
Post by: Noopy on October 04, 2021, 07:31:29 pm
(https://richis-lab.de/images/transistoren/a20x01.jpg)

(https://richis-lab.de/images/transistoren/a20x02.jpg)

BC149B, a old transistor in an old package (SOT-25) built by many manufacturers.
20V, 50mA, 350MHz but the different manufacturers had sometimes different specifications.


(https://richis-lab.de/images/transistoren/a20x03.jpg)

(https://richis-lab.de/images/transistoren/a20x04.jpg)

The edge length of the die is 0,35mm.


(https://richis-lab.de/images/transistoren/a21x01.jpg)

(https://richis-lab.de/images/transistoren/a21x02.jpg)

"DE9", a different datecode?


(https://richis-lab.de/images/transistoren/a21x03.jpg)

(https://richis-lab.de/images/transistoren/a21x04.jpg)

There is a little difference, there is just one alignment structure in the upper right corner.


https://richis-lab.de/Bipolar77.htm (https://richis-lab.de/Bipolar77.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 05, 2021, 03:47:35 am
(https://www.richis-lab.de/images/transistoren/a22x01.jpg)

BC158, a complementary type to the BC149B (but not the low noise one, that would be the BC159).


(https://www.richis-lab.de/images/transistoren/a22x03.jpg)

(https://www.richis-lab.de/images/transistoren/a22x04.jpg)

The design is a little different.  :-/O


https://www.richis-lab.de/Bipolar78.htm (https://www.richis-lab.de/Bipolar78.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 09, 2021, 06:32:04 pm
(https://www.richis-lab.de/images/transistoren/a23x01.jpg)

SL3127, a fast transistor array built by Plessey Semiconductors. There are five transistors with a ft of 1,6Ghz at 5mA collector current. The maximum collector emitter voltage is 18V. The base emitter voltages differ no more than 5mV.
There is a substrate contact which you have to connect to the most negative voltage of the transistors. You can also use a more negative potential. That reduces the leakage current and the parasitic capacitance. Maximum collector substrate voltage is 55V typ. (but only 20V min.!).


(https://www.richis-lab.de/images/transistoren/a23x03.jpg)

(https://www.richis-lab.de/images/transistoren/a23x04.jpg)

The die is 1,1mm x 1,0mm. WH047B is the internal name. There are a lot of structures to check the process quality.
There are six transistors. The unused one is shorted with a metal strip. There is also an unused substrate contact. With a different metal layer you get a different circuit.


(https://www.richis-lab.de/images/transistoren/a23x05.jpg)

(https://www.richis-lab.de/images/transistoren/a23x06.jpg)

(https://www.richis-lab.de/images/transistoren/a23x07.jpg)

The brown area is the collector area (n) isolated from the green area (p). The collector potential is connected at the top and at the bottom of the transistor. It looks like there is an area around the collector contact. That is probably an area with higher doping for low resistance in the collector path.
Base and emitter are a little strange. There is a big rectangle which is connected to the emitter pin by two vias. There are three base contacts which seem to contact three smaller areas in the emitter rectangle. Such an arrangement only makes sense if it´s a perforated emitter like structure.


https://www.richis-lab.de/Bipolar79.htm (https://www.richis-lab.de/Bipolar79.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 10, 2021, 09:12:31 am
(https://www.richis-lab.de/images/transistoren/a24x01.jpg)

The SL3145 and the SL3127 share the same datasheet.


(https://www.richis-lab.de/images/transistoren/a24x03.jpg)

The SL3145 gives you 5 transistors too. It´s packaged in a smaller package (DIL-14 vs. DIL-16). To reduce the pincount there are two emitters connected for a differential stage and the substrate is connected to these two emitters.


(https://www.richis-lab.de/images/transistoren/a24x04.jpg)

(https://www.richis-lab.de/images/transistoren/a24x05.jpg)

No surprise: The die is basically the same as the die in the SL3127 but the metal layer is different. The SL3145 uses the upper substrate contact, the transistor in the middle of the upper line is shorted and the transistors in the lower right corner are connected together (connections of collector and emitter are quite similar to get a good matching of the differential stage). The internal naming is WH047A (vs. WH047B).


https://www.richis-lab.de/Bipolar80.htm (https://www.richis-lab.de/Bipolar80.htm)

 :-+
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on October 10, 2021, 02:45:20 pm
The substrate is connected to another emitter, rather.

A likely application for this arrangement (also CA3086, LM3086 etc.) is the substrate-emitter transistor serves as current sink, the common-emitter pair is the diff pair on top of it, and the other two can be used for whatever, maybe cascode or follower at the diff amp collectors.  (Another monolithic pair would be needed for PNP current mirrors, if using that type of design.  Would be handy if they put PNPs into the same package, but alas.)  Gain depends on bias (no external resistance between emitters), so this is useful for mixers and variable-gain (OTA) circuits as well as plain old amplifiers.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on October 10, 2021, 02:55:46 pm
The substrate is connected to another emitter, rather.

Correct, that was a mistake on my side. Sorry!

A likely application for this arrangement (also CA3086, LM3086 etc.) is the substrate-emitter transistor serves as current sink, the common-emitter pair is the diff pair on top of it, and the other two can be used for whatever, maybe cascode or follower at the diff amp collectors.  (Another monolithic pair would be needed for PNP current mirrors, if using that type of design.  Would be handy if they put PNPs into the same package, but alas.)  Gain depends on bias (no external resistance between emitters), so this is useful for mixers and variable-gain (OTA) circuits as well as plain old amplifiers.

The five transistors are ideal to built mixer stages, "Gilbert-Zelle" in Germany.
https://de.m.wikipedia.org/wiki/Gilbertzelle (https://de.m.wikipedia.org/wiki/Gilbertzelle)
Title: Re: Transistors - die pictures
Post by: Noopy on October 10, 2021, 03:06:16 pm
Wait a moment! That is strange:


(https://www.richis-lab.de/images/transistoren/a24x02.jpg)

In the datasheet for the SL3145 the substrate is connected to the two emitters of the differential pair transistors!
(For example here: https://datasheetspdf.com/pdf-file/270949/ZarlinkSemiconductorInc/SL3145/1 (https://datasheetspdf.com/pdf-file/270949/ZarlinkSemiconductorInc/SL3145/1))
That is odd...  :-//
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on October 10, 2021, 04:15:45 pm
Uh.. that's interesting!

I wonder how many people got burned by that!?  Or maybe they changed it along the way?

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on October 10, 2021, 04:29:15 pm
I found three different datasheets but all of them showed substrate at pin 3.
Would be a strange change during.  ;D  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on October 10, 2021, 08:31:33 pm
The datasheet of the SL3145 explains that it can replace the SL3045. The datasheet of the SL3045 shows the substrate connected to T5:
https://www.datasheetarchive.com/pdf/download.php?id=a3525a182d942a45d57edcaa2f3f915488d2b5&type=M&term=SL3045 (https://www.datasheetarchive.com/pdf/download.php?id=a3525a182d942a45d57edcaa2f3f915488d2b5&type=M&term=SL3045)
Nevertheless that doesn´t help developers that start with the SL3145.
Title: Re: Transistors - die pictures
Post by: Noopy on October 13, 2021, 06:31:28 am
(https://www.richis-lab.de/images/transistoren/a25x01.jpg)

The Gleichrichterwerk Stahnsdorf had built a MJ3001 too.


(https://www.richis-lab.de/images/transistoren/a25x02.jpg)

(https://www.richis-lab.de/images/transistoren/a25x03.jpg)

There is the red potting we often have seen in "eastern" transistors.
In the SU111 they used two different bondwire diameters (https://www.richis-lab.de/Bipolar59.htm (https://www.richis-lab.de/Bipolar59.htm)). In the MJ3001 they used only one diameter and two of them for the emitter contact.


(https://www.richis-lab.de/images/transistoren/a25x04.jpg)

The die is orientated in a way you are able to bond the wires as good as possible.


(https://www.richis-lab.de/images/transistoren/a25x05.jpg)

The die looks like the die in the SU111 (https://www.richis-lab.de/Bipolar59.htm (https://www.richis-lab.de/Bipolar59.htm)). It´s quite possible they used the same die here, perhaps a different bin of the SU111. The SU111 can conduct the same current as the Motorola MJ3001 (https://www.richis-lab.de/Bipolar60.htm (https://www.richis-lab.de/Bipolar60.htm)) but the maximum Vce is a lot higher (400V).


(https://www.richis-lab.de/images/transistoren/a25x06.jpg)

The edge of the die is a little different. In the SU111 the MESA structure left a small strip that is removed nearly completely in the MJ3001. Just in the corners there is a little "tower" left.


https://www.richis-lab.de/Bipolar81.htm (https://www.richis-lab.de/Bipolar81.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 22, 2021, 03:32:55 am
(https://www.richis-lab.de/images/transistoren/a26x01.jpg)

(https://www.richis-lab.de/images/transistoren/a26x02.jpg)

Honeywell 2N1262, a very old Ge power transistor (45V, 3,5A, 32W, 0,2MHz) built by Honeywell.


(https://www.richis-lab.de/images/transistoren/a26x11.jpg)

A 2N1262 ad back in the year 1959 (Electronic Design, December 9, 1959).


(https://www.richis-lab.de/images/transistoren/a26x03.jpg)

Heat spreading with copper. The package is MT-36.


(https://www.richis-lab.de/images/transistoren/a26x04.jpg)

Nice!  8)


(https://www.richis-lab.de/images/transistoren/a26x06.jpg)

The 2N1262 is hard to disassemble because the contact pins are shells in which the contact wires are squeezed...


(https://www.richis-lab.de/images/transistoren/a26x07.jpg)

...and because of that the transistor broke.  :-\
There is a small rectangle germanium plate contacted with a metal ring which is the base contact. In the middle there is the emitter contact.


(https://www.richis-lab.de/images/transistoren/a26x08.jpg)

The germanium plate sits on a copper socket that is the collector contact and removes heat.


(https://www.richis-lab.de/images/transistoren/a26x09.jpg)

(https://www.richis-lab.de/images/transistoren/a26x10.jpg)

Collector area is bigger than emitter area and the active area is a little thinner than the rest of the plate. Both facts improve the transistor specs.


https://www.richis-lab.de/Bipolar82.htm (https://www.richis-lab.de/Bipolar82.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: salihkanber on October 22, 2021, 07:50:44 pm
Those looks like true art 👍
Title: Re: Transistors - die pictures
Post by: Noopy on October 27, 2021, 07:24:07 am
(https://www.richis-lab.de/images/transistoren/a27x01.jpg)

(https://www.richis-lab.de/images/transistoren/a27x08.jpg)

(https://www.richis-lab.de/images/transistoren/a27x02.jpg)

Let´s take a look into a SMY60, a Dual-p-MOSFET built by the Funkwerk Erfurt.
The SMY60 has no protection diodes. To protect the MOSFETs against ESD there is a copper clamp above the package shorting all pins. After soldering the SMY60 into a circuit you can remove the clamp.
K stands for a production in the year 1977.
(-25V/20mA)


(https://www.richis-lab.de/images/transistoren/a27x03.jpg)

The datasheet shows that the bulk contacts of the two MOSFETs are connected but they are not connected to the source contacts.
Although it can conduct twice the current of the SMY51 (https://www.richis-lab.de/FET09.htm (https://www.richis-lab.de/FET09.htm)) the gate capacity is a little lower: 10pF vs. 12pF. One explanation for the lower gate charge is that the SMY51 contains protection diodes.


(https://www.richis-lab.de/images/transistoren/a27x04.jpg)

(https://www.richis-lab.de/images/transistoren/a27x05.jpg)

The die was protected with some silicone like potting. It is 1,1mm x 0,9mm, a little bigger than the SMY51 but the sizes of the transistors are quite similar. The gate electrodes are a little less overlapping in the SMY60. That could be another small share to the smaller gate capacity. In the upper right area there are four squares to check the manufacturing quality. The 2222 shows the revisions of the masks.

The two MOSFETs are integrated side by side to get them most equal in terms of production and temperature. On the left side we have the bulk connection. This potential is guided around the die and between the two MOSFETs to get some shielding.

You can see the meshed drain and source areas. They are a little unsymmetrical and it seems there are different doping levels too. The datasheet states a Source-Bulk breakdown voltage of -15V and a Drain-Bulk breakdown voltage of -25V. The source area seems to be doped more heavily.


(https://www.richis-lab.de/images/transistoren/a27x06.jpg)

(https://www.richis-lab.de/images/transistoren/a27x07.jpg)

After removing some of the metal layer we can take a closer look at the MOSFET.
The field oxide (FOX) had been removed in the area where the MOSFET was integrated. The substrate is p-doped. The area of source and drain got n-doped. Between source and drain there is the p-doped channel left. The channel width is something around 8-9µm.
Left and right of the MOSFET there are vias to contact source and drain with the metal layer.
The yellowish part is the thin gate oxide (GOX). In this area the potential of the metal layer influences the resistance of the channel. In the areas around the GOX the silicone oxide is a little thicker but still thinner than the FOX.


https://www.richis-lab.de/FET20.htm (https://www.richis-lab.de/FET20.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 11, 2021, 06:47:10 am
(https://www.richis-lab.de/images/transistoren/a28x01.jpg)

(https://www.richis-lab.de/images/transistoren/a28x02.jpg)

(https://www.richis-lab.de/images/transistoren/a28x03.jpg)

2N6485, a Dual-JFET built by several companies. This one is from Harris Semiconductor. Datasheet says it is especially suitable for low frequency low noise applications (50V / 7,5mA)
2N6483, 2N6484 and 2N6485 are different grades with different offset voltages. 2N6485 is the worst one with up to 15mV.


(https://www.richis-lab.de/images/transistoren/a28x04.jpg)

The die is quite big. The pins are properly separated.


(https://www.richis-lab.de/images/transistoren/a28x05.jpg)

(https://www.richis-lab.de/images/transistoren/a28x06.jpg)

You can easily spot the red p-doped gate electrode. Under the gate electrode there is the n-channel placed in a p-doped substrate. The inner contact is drain. The outer contacts are source.


https://www.richis-lab.de/FET21.htm (https://www.richis-lab.de/FET21.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 15, 2021, 04:38:51 am
(https://www.richis-lab.de/images/transistoren/a29x01.jpg)

One more 2N3055, a Siemens 2N3055H. It looks like Siemens marked its 2N3055 similar to RCA (https://www.richis-lab.de/2N3055_08.htm (https://www.richis-lab.de/2N3055_08.htm)): First all 2N3055 were hometaxial. With the new epitaxial 2N3055 the hometaxial were named 2N3055H.


(https://www.richis-lab.de/images/transistoren/a29x02.jpg)

(https://www.richis-lab.de/images/transistoren/a29x03.jpg)

Compared to the old Siemens 2N3055 (https://www.richis-lab.de/2N3055_01.htm (https://www.richis-lab.de/2N3055_01.htm)) this one is really modern!  ;D


(https://www.richis-lab.de/images/transistoren/a29x04.jpg)

The die looks quite similar to the other hometaxial 2N3055.
But there is some interesting damage...


(https://www.richis-lab.de/images/transistoren/a29x05.jpg)

On the left emitter electrode there is only a small damage. On the right side the transparent coating is ripped.  >:D


https://www.richis-lab.de/2N3055_14.htm (https://www.richis-lab.de/2N3055_14.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 21, 2021, 04:49:58 am
(https://www.richis-lab.de/images/transistoren/a30x01.jpg)

Have you ever heard of the company "Solid State"? Try to search for information about a company named "Solid State"!  ;D


(https://www.richis-lab.de/images/transistoren/a30x02.jpg)

The 2N3752 is a power transistor in a TO-111 package that can be screwed into a heat sink and dissipate up to 30W of power at 100°C. It can isolate 80V and conduct up to 1A. Cutoff frequency is 50MHz. The transistor is isolated from the package, which has four connections for this reason.


(https://www.richis-lab.de/images/transistoren/a30x03.jpg)

A B * ? I don´t know what that means...


(https://www.richis-lab.de/images/transistoren/a30x04.jpg)

(https://www.richis-lab.de/images/transistoren/a30x05.jpg)

(https://www.richis-lab.de/images/transistoren/a30x06.jpg)

The upper part of the transistor cannot be removed completely without damaging it. In the lower part, three pins are molded in three holes and contact the transistor and its carrier. After putting on the upper part the pins move into the connectors of the housing which are bushings (not sure whether that´s the right name) at the bottom. After assembly, the bushings are pressed together.


(https://www.richis-lab.de/images/transistoren/a30x07.jpg)

The die is on a round element that isolates it from the case. On the right side of the element, a piece of the metallization and the die is torn off. The white material is probably beryllium oxide which insulates electrically but still dissipates power reasonably well.


(https://www.richis-lab.de/images/transistoren/a30x08.jpg)

The die has no special structure. The emitter (blue) is placed in a base area (pink). The metallization has some scratches. On the right edge there is a missing part.


(https://www.richis-lab.de/images/transistoren/a30x09.jpg)

The junction is a little messy and the metal layer is no aligned perfectly but it´s ok.


(https://www.richis-lab.de/images/transistoren/a30x10.jpg)

Viewed from the side one can see that the emitter area is somewhat elevated compared to the base area. This would fit to an epitaxially grown emitter. The contact areas are gray. The contact area of the base shows some height difference at the edge too. This is the breakthrough through the insulating passivation layer.


https://www.richis-lab.de/Bipolar83.htm (https://www.richis-lab.de/Bipolar83.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on November 21, 2021, 06:24:33 pm
No glowing pictures? :)
Title: Re: Transistors - die pictures
Post by: Noopy on November 21, 2021, 06:27:13 pm
No good connections left.  ;D
And it's a ordinary transistor. We have seen a lot of them glowing.  ;)
Title: Re: Transistors - die pictures
Post by: David Hess on November 22, 2021, 05:43:55 am
Have you ever heard of the company "Solid State"? Try to search for information about a company named "Solid State"!  ;D

...

The 2N3752 is a power transistor in a TO-111 package that can be screwed into a heat sink and dissipate up to 30W of power at 100°C. It can isolate 80V and conduct up to 1A. Cutoff frequency is 50MHz. The transistor is isolated from the package, which has four connections for this reason.

I am sure I have some of those in my junk box.  I never found a use for them.
Title: Re: Transistors - die pictures
Post by: Noopy on November 29, 2021, 09:11:17 am
(https://www.richis-lab.de/images/transistoren/a31x01.jpg)

The ГT906 (GT906) is a germanium power transistor that can block up to 75V. Maximum collector current is 10A. Up to 15W can be dissipated through the package. The temperature of the die must remain below 75°C. The cutoff frequency is 30MHz.
You can´t identify the manufacturer.  :-// The second line could be a date code (1981).


(https://www.richis-lab.de/images/transistoren/a31x02.jpg)

(https://www.richis-lab.de/images/transistoren/a31x03.jpg)

The pin holes looks a little sloppy.


(https://www.richis-lab.de/images/transistoren/a31x04.jpg)

A dry agent.


(https://www.richis-lab.de/images/transistoren/a31x05.jpg)

(https://www.richis-lab.de/images/transistoren/a31x11.jpg)

That´s an interesting pin conduct.


(https://www.richis-lab.de/images/transistoren/a31x06.jpg)

(https://www.richis-lab.de/images/transistoren/a31x07.jpg)

The design of the GT906 looks similar to the Philips AU103 (https://www.richis-lab.de/Bipolar03.htm (https://www.richis-lab.de/Bipolar03.htm)). The diameter of the germanium disk is round about 6,8mm. There are three solder circles that are connected with the pins.


(https://www.richis-lab.de/images/transistoren/a31x09.jpg)

(https://www.richis-lab.de/images/transistoren/a31x08.jpg)

The inner and the outer ring are connected to the base pin. The ring in the middle is connected to the emitter pin.


(https://www.richis-lab.de/images/transistoren/a31x14.jpg)

The GT906 is a post-alloy diffused transistor (PADT). The picture above shows how the structures of the transistor probably look like. It is taken from "Einführung in die Physik des Transistors" written by W.W. Gärtner.
You start with a p-doped slice that is the collector. Then you put Pb-Sb on the slice where you want to get a base contact and Pb-Sb-Al where you want to get the emitter contact. After a heat treatment these elements are alloyed with the germanium slice. Since Sb diffuses faster than Al you always have a n-doped layer (Sb) under the p-doped emitter area (Al).  :-+
Sometimes PADTs are manufactured in two steps and there is a diffusion process before the alloying. The diffusion brings an initial base layer into the slice. It seems like this was done a lot with HF transistors like the 2N1561 (https://www.richis-lab.de/Bipolar17.htm (https://www.richis-lab.de/Bipolar17.htm)).


(https://www.richis-lab.de/images/transistoren/a31x10.jpg)

Base and emitter ring have to be located as near as possible to get low resistances to the active area.
You can see the different structures of the rings probably due to the different materials.
Looks like there is a transparent protective coating on top of the die.


(https://www.richis-lab.de/images/transistoren/a31x12.jpg)

(https://www.richis-lab.de/images/transistoren/a31x13.jpg)

The thickness of the germanium slice is only round about 20µm. It is placed on a carrier with a height of 0.3mm.
The germanium slice must be very thin so the collector resistance doesn´t get too high. If we assume a specific resistance of 5Ωcm as shown in the book above, a diameter of 6,8mm and a thickness of 20µm gives you a path resistance of 28mΩ. At the maximum current of 10A you get 2.8W of power loss in this area!


https://www.richis-lab.de/Bipolar84.htm (https://www.richis-lab.de/Bipolar84.htm)

 :-/O


In addition I have updated:
2N1561 https://www.richis-lab.de/Bipolar17.htm (https://www.richis-lab.de/Bipolar17.htm)
AU103 https://www.richis-lab.de/Bipolar03.htm (https://www.richis-lab.de/Bipolar03.htm)
Title: Re: Transistors - die pictures
Post by: Miyuki on November 29, 2021, 09:50:32 am
Wow those weird patterns
It is so nice 🖤
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2021, 04:32:14 am
(https://www.richis-lab.de/images/transistoren/a32x01.jpg)

2N3055 built by SGS ATES (today ST Microelectronics).


(https://www.richis-lab.de/images/transistoren/a32x02.jpg)

(https://www.richis-lab.de/images/transistoren/a32x03.jpg)

The logo is really hard to identify.


(https://www.richis-lab.de/images/transistoren/a32x04.jpg)

(https://www.richis-lab.de/images/transistoren/a32x05.jpg)

(https://www.richis-lab.de/images/transistoren/a32x06.jpg)

A hometaxial transistor, nothing special. A big heatspreader with trenches to drain solder. There is a big solder blob on the right side.  :-// It looks like the contact sheets had some kind of coating.


(https://www.richis-lab.de/images/transistoren/a32x07.jpg)

The die looked fine but there had so be a defect because I wasn´t able to drive BE in breakdown but instead at higher currents (3A) I got a funny glow destroying the structures.  >:D
I did a small video: https://www.richis-lab.de/images/transistoren/a32x07.mp4 (https://www.richis-lab.de/images/transistoren/a32x07.mp4)


https://www.richis-lab.de/2N3055_15.htm (https://www.richis-lab.de/2N3055_15.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2021, 03:46:12 am
(https://www.richis-lab.de/images/transistoren/a33x01.jpg)

Besides the 2N3055 SGS ATES did some other versions of the 2N3055. Probably they binned the transistors. I found datasheets for the 2N3055C (Ucb a little lower) and for the 2N3055U (higher Uce0, no second breakdown). Unfortunately there is no data for the 2N3055VT.


(https://www.richis-lab.de/images/transistoren/a33x02.jpg)

(https://www.richis-lab.de/images/transistoren/a33x03.jpg)

It looks a little older than the 2N3055.


(https://www.richis-lab.de/images/transistoren/a33x04.jpg)

The die took damage at the upper edge. Additional left of the left contact the coating is ruined.


(https://www.richis-lab.de/images/transistoren/a33x05.jpg)

Looks like there was a base collector flashover.


https://www.richis-lab.de/2N3055_16.htm (https://www.richis-lab.de/2N3055_16.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on December 08, 2021, 04:00:10 am
Speculation, V might be high voltage.  There were some -HV variants by others.  That might even be suggested by the flashover..!  Though still not because of sheer voltage alone, that would be crazy, but I wonder maybe if there were tin whiskers somewhere inside that did it in?  (Any roughness on the package?)

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2021, 06:03:29 am
"high voltage" is at least possible.  :-+

I didn´t find hints of tin whiskers but I wouldn´t rule them out.  :-//
Title: Re: Transistors - die pictures
Post by: quadtech on December 08, 2021, 03:55:18 pm
The 2N6485 die shot reminded me of this one of INT591A from Zeptobars -

https://zeptobars.com/en/read/1NT591A-double-bjt-transistor-array-differential-amplifier
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2021, 05:01:14 pm
The 2N6485 die shot reminded me of this one of INT591A from Zeptobars -

https://zeptobars.com/en/read/1NT591A-double-bjt-transistor-array-differential-amplifier (https://zeptobars.com/en/read/1NT591A-double-bjt-transistor-array-differential-amplifier)

You are talking about the 1HT291Б (K1NT291B)?
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3651136/#msg3651136 (https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3651136/#msg3651136)

Yes, this one is quite similar to the INT591A.
Title: Re: Transistors - die pictures
Post by: Noopy on December 12, 2021, 04:23:52 am
(https://www.richis-lab.de/images/transistoren/a34x01.jpg)

(https://www.richis-lab.de/images/transistoren/a34x02.jpg)

GD170, a PNP-Ge-Transistor built in the Halbleiterwerk Frankfurt Oder. 30V/3A/180kHz/5,3W@25°C and a hfe between 18 and 90.  ;D
In fact nothing very special.


(https://www.richis-lab.de/images/transistoren/a34x03.jpg)

Quite a big drying agent disk.


(https://www.richis-lab.de/images/transistoren/a34x04.jpg)

That´s a big base ring. They even had to cut it so it can fit into the package!
Emitter connection is done with a pin.
The transistor is coated to protect it against the environment.


(https://www.richis-lab.de/images/transistoren/a34x05.jpg)

The connector pins were treated somehow and there are some fibers probably due to the treatment.


(https://www.richis-lab.de/images/transistoren/a34x06.jpg)


https://www.richis-lab.de/Bipolar85.htm (https://www.richis-lab.de/Bipolar85.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on December 12, 2021, 05:30:44 am
GD170, a PNP-Ge-Transistor built in the Halbleiterwerk Frankfurt Oder. 30V/3A/180kHz/5,3W@25°C and a hfe between 18 and 90.  ;D
In fact nothing very special.

It could have especially low saturation. :)

Germanium transistors do have lower Vce(sat) than silicon transistors.
Title: Re: Transistors - die pictures
Post by: SeanB on December 12, 2021, 06:13:05 am
Those fibres are the cotton cloth used to apply the conformal coat. Probably the original die was meant to be used in a TO3 can, and instead they decided to use them in the TO66 package instead.

Looks like they made them with the emitter as a long length of wire laid down on the indium preform blocks, then sent the lot through an over to melt the Indium and diffuse it, afterwards shearing off the base tab, so they could test the individual transistors, before cutting the emitter rod to separate them. Then placed in the kovar base, and a drop of solder paste base and emitter, then a final oven trip to solder the collector and mount the can.

Wonder what the reject rate was, they must have gotten it over 90% pass by the end of production. Wide Hfe range, they really probably all fell in the area of 40 to 60, as that is very process dependent, and if you can control the process steps time and temperature wise you can get a close spread.
Title: Re: Transistors - die pictures
Post by: Noopy on December 12, 2021, 07:08:05 am
It could have especially low saturation. :)

Germanium transistors do have lower Vce(sat) than silicon transistors.

<0,6V @3A  :-+


...

Sounds reasonable.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on December 26, 2021, 04:11:27 am
(https://www.richis-lab.de/images/transistoren/a35x01.jpg)

Motorola 2N3614, 35V, 7A continues, 15A peak, 77W @25°C case temperature.


(https://www.richis-lab.de/images/transistoren/a35x02.jpg)

(https://www.richis-lab.de/images/transistoren/a35x03.jpg)

There are two metal sheets contacting base and emitter which were initially connected.


(https://www.richis-lab.de/images/transistoren/a35x06.jpg)

(https://www.richis-lab.de/images/transistoren/a35x07.jpg)

There is a n-doped germanium slice acting as base region. The p-doped emitter and collector areas are alloyed into the two sides of the base slice.


(https://www.richis-lab.de/images/transistoren/a35x04.jpg)

(https://www.richis-lab.de/images/transistoren/a35x05.jpg)

There are two metal sheets. In the first place the base metal sheet is fixed by the two contact pins. The emitter metal sheet is fixed by the emitter pin and a hole in the base metal sheet. Taken together this construction assures that the emitter contact is in the middle of the germanium slice. The base metal sheet is cut at the hole where there is only one metal sheet and the cross section is lowest.


https://www.richis-lab.de/Bipolar86.htm (https://www.richis-lab.de/Bipolar86.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on December 26, 2021, 09:50:26 am
Wow, those tilted shots are amazing!   :-+
Title: Re: Transistors - die pictures
Post by: SilverSolder on December 27, 2021, 03:22:29 pm

Focus stacking taken to new heights!  :D
Title: Re: Transistors - die pictures
Post by: David Hess on December 27, 2021, 03:50:43 pm
Focus stacking taken to new heights!  :D

It takes bright light to allow for a narrow aperture for large depth of field.  I have taken to manually setting the aperture of my camera as small as possible but it only goes down to F8.
Title: Re: Transistors - die pictures
Post by: Noopy on December 27, 2021, 03:54:54 pm
With a narrow aperture you get problems at high magnifications due to diffraction. So you better work with wide apertures, a lot of pictures and focus stacking.
I have added 3TB to my NAS.  ;D
Title: Re: Transistors - die pictures
Post by: David Hess on December 27, 2021, 04:22:00 pm
With a narrow aperture you get problems at high magnifications due to diffraction. So you better work with wide apertures, a lot of pictures and focus stacking.

But that would be cheating.
Title: Re: Transistors - die pictures
Post by: Noopy on December 27, 2021, 04:33:11 pm
With a narrow aperture you get problems at high magnifications due to diffraction. So you better work with wide apertures, a lot of pictures and focus stacking.

But that would be cheating.

Just compensating the limitations of camera optics.  :-/O :-+
Title: Re: Transistors - die pictures
Post by: mawyatt on December 27, 2021, 04:58:15 pm
With a narrow aperture you get problems at high magnifications due to diffraction. So you better work with wide apertures, a lot of pictures and focus stacking.

But that would be cheating.

Been "cheating" for 20 years ;D

Best,
Title: Re: Transistors - die pictures
Post by: mawyatt on December 27, 2021, 05:06:51 pm

Motorola 2N3614, 35V, 7A continues, 15A peak, 77W @25°C case temperature.



There are two metal sheets contacting base and emitter which were initially connected.


(https://www.richis-lab.de/images/transistoren/a35x06.jpg)

(https://www.richis-lab.de/images/transistoren/a35x07.jpg)

There is a n-doped germanium slice acting as base region. The p-doped emitter and collector areas are alloyed into the two sides of the base slice.


(https://www.richis-lab.de/images/transistoren/a35x04.jpg)

(https://www.richis-lab.de/images/transistoren/a35x05.jpg)

There are two metal sheets. In the first place the base metal sheet is fixed by the two contact pins. The emitter metal sheet is fixed by the emitter pin and a hole in the base metal sheet. Taken together this construction assures that the emitter contact is in the middle of the germanium slice. The base metal sheet is cut at the hole where there is only one metal sheet and the cross section is lowest.


https://www.richis-lab.de/Bipolar86.htm (https://www.richis-lab.de/Bipolar86.htm)

 :-/O

Nice 3D look!!

Well done  :clap:

Are you using Zerene for stacking?

Now it's time to really "cheat" with Stack & Stitch  >:D

Best,
Title: Re: Transistors - die pictures
Post by: mawyatt on December 27, 2021, 05:10:50 pm
With a narrow aperture you get problems at high magnifications due to diffraction. So you better work with wide apertures, a lot of pictures and focus stacking.
I have added 3TB to my NAS.  ;D

Exactly :-+

Best
Title: Re: Transistors - die pictures
Post by: Noopy on December 27, 2021, 05:21:19 pm
Thanks!

I'm using Helicon Focus for stacking. Works quite well for me.
On some pictures you can find some smaller artefacts but I won't blame the software. I often have very complex pictures: thin bondwires with small distance to big planes, hard edges and wide areas with some delicate pattern, mirroring and so on...  :phew: That isn't an easy task!
Title: Re: Transistors - die pictures
Post by: David Hess on December 28, 2021, 04:39:42 am
I may try experimenting with that since I have Magic Lantern installed which in theory supports focus bracketing on my Canon PowerShot SX150 IS that I use for macro photography.  Recently I have concentrated on getting better lighting with a ring light which helped a lot although glare has been a problem.  I need to improve the diffusion with something like a cone.
Title: Re: Transistors - die pictures
Post by: Noopy on December 28, 2021, 07:36:39 am
I have tried a lot of different light sources. For "small" parts like a single TO-3 a very simple but good solution is a normal sheet of paper folded like a simple tent. A common desk light gives you a very broad light with respect to small parts. The paper tent adds diffusion.
The amount of light is irrelevant if you do long term exposure. I would recommend this.
For bigger objects that's not the best solution...
Title: Re: Transistors - die pictures
Post by: mawyatt on December 29, 2021, 02:05:36 am
For smaller objects white styrofoam cups work well, but they eat lots of light and thus usually require bright LEDs or strobe/speedlight. As Noopy indicated you can use good white paper folded into a tent or rolled up into a cone. With any diffusion and various light sources be sure to do a good white balance.

A few years ago we did some modifications to a cheap IKEA LED light.

https://www.photomacrography.net/forum/viewtopic.php?f=25&t=41464&hilit=Jansjo (https://www.photomacrography.net/forum/viewtopic.php?f=25&t=41464&hilit=Jansjo)

And a higher output Godox LED light.

https://www.photomacrography.net/forum/viewtopic.php?f=25&t=41353&p=264797&hilit=Jansjo#p264797 (https://www.photomacrography.net/forum/viewtopic.php?f=25&t=41353&p=264797&hilit=Jansjo#p264797)

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on December 30, 2021, 03:59:08 pm
(https://www.richis-lab.de/images/transistoren/a36x01.jpg)

Tesla KD616, a PNP power transistor for linear applications. It´s the complementary part to the KD606.
60V, 10A, 2MHz, hfe>30 @1A


(https://www.richis-lab.de/images/transistoren/a36x02.jpg)

B and E, so you know where to find the right potential.  :-+


(https://www.richis-lab.de/images/transistoren/a36x03.jpg)

(https://www.richis-lab.de/images/transistoren/a36x04.jpg)

We know these Tesla transistors with the red potting.


(https://www.richis-lab.de/images/transistoren/a36x05.jpg)

The potting doesn´t stick very hard but it´s still not easy to remove it completely.


(https://www.richis-lab.de/images/transistoren/a36x06.jpg)

(https://www.richis-lab.de/images/transistoren/a36x07.jpg)

The die is quite similar to  the KD605 (https://www.richis-lab.de/Bipolar46.htm (https://www.richis-lab.de/Bipolar46.htm)). I assume the KD60x (NPN) and the KD61x (PNP) are the same transistors just binned to different voltage ratings.


(https://www.richis-lab.de/images/transistoren/a36x11.jpg)

There is a square hole in the metal layer. You can see a square in the silicon underneath. This way you can check the mask alignment.


(https://www.richis-lab.de/images/transistoren/a36x08.jpg)

(https://www.richis-lab.de/images/transistoren/a36x09.jpg)

Here you can see the different colors of base and emitter. At the edges of the metal at some places you can see the step of the hole in the SiO2 isolation through which the metal can contact the silicon.
The MESA edge is quite poor compared to the KD605 (https://www.richis-lab.de/Bipolar46.htm (https://www.richis-lab.de/Bipolar46.htm)). That´s probably due to the age. KD616 is "IV" => May 1979. KD605 is "S6" => June 1984. It seems like they have improved the process.


(https://www.richis-lab.de/images/transistoren/a36x10.jpg)

Viewed sideways you can see how inhomogeneous the etching ist.


https://www.richis-lab.de/Bipolar87.htm (https://www.richis-lab.de/Bipolar87.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 07, 2022, 05:08:09 am
(https://www.richis-lab.de/images/transistoren/a37x01.jpg)

(https://www.richis-lab.de/images/transistoren/a37x02.jpg)

The OC45 was made by a lot of companies. I don´t know which one produced this one.
Compared to the OC811 (https://www.richis-lab.de/Bipolar53.htm (https://www.richis-lab.de/Bipolar53.htm)) the OC45 is a high frequency transistor which can switch up to 4MHz.


(https://www.richis-lab.de/images/transistoren/a37x03.jpg)

(https://www.richis-lab.de/images/transistoren/a37x04.jpg)

You can scrape off the black paint that protects the transistor against light.
In the glass housing there is a blue potting.


(https://www.richis-lab.de/images/transistoren/a37x05.jpg)

Looks like silicon.


(https://www.richis-lab.de/images/transistoren/a37x06.jpg)

You can remove the blue stuff with paint stripper.
At the transistor there are bulges around the contact wires. Perhaps there is an additional protective coating.


(https://www.richis-lab.de/images/transistoren/a37x07.jpg)

(https://www.richis-lab.de/images/transistoren/a37x08.jpg)

After the treatment with lack stripper the transistor is clean.
At the pin in the middle there is the base ring contact.


(https://www.richis-lab.de/images/transistoren/a37x11.jpg)

(https://www.richis-lab.de/images/transistoren/a37x12.jpg)

(https://www.richis-lab.de/images/transistoren/a37x13.jpg)

The plate is 1,4mm in diameter.


(https://www.richis-lab.de/images/transistoren/a37x09.jpg)

The height of the germanium plate is just 40µm.


(https://www.richis-lab.de/images/transistoren/a37x10.jpg)

(https://www.richis-lab.de/images/transistoren/a37x14.jpg)

Emitter


https://www.richis-lab.de/Bipolar88.htm (https://www.richis-lab.de/Bipolar88.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on January 07, 2022, 07:37:11 am
Were those devices packaged manually? I wonder how difficult it was to solder them.
Title: Re: Transistors - die pictures
Post by: Noopy on January 07, 2022, 09:20:31 am
I don't know for the OC45 but it seems there was a lot handcraft back in the days:
https://www.thevalvepage.com/trans/manufac/manufac1.htm (https://www.thevalvepage.com/trans/manufac/manufac1.htm)
Title: Re: Transistors - die pictures
Post by: eutectique on January 07, 2022, 01:55:08 pm

The ГT906 (GT906) is a germanium power transistor that can block up to 75V. ... The second line could be a date code (1981).

It is February 1981, indeed. Soviet manufacturers used to mark production month with Roman numerals.
Title: Re: Transistors - die pictures
Post by: mawyatt on January 07, 2022, 04:25:11 pm
Interesting old transistor, great images :-+

Best,
Title: Re: Transistors - die pictures
Post by: Miyuki on January 11, 2022, 08:16:48 pm
I don't know for the OC45 but it seems there was a lot handcraft back in the days:
https://www.thevalvepage.com/trans/manufac/manufac1.htm (https://www.thevalvepage.com/trans/manufac/manufac1.htm)
No wonder it used to cost a fortune
Title: Re: Transistors - die pictures
Post by: Noopy on January 11, 2022, 08:56:03 pm
I don't know for the OC45 but it seems there was a lot handcraft back in the days:
https://www.thevalvepage.com/trans/manufac/manufac1.htm (https://www.thevalvepage.com/trans/manufac/manufac1.htm)
No wonder it used to cost a fortune


Quote from: www.thevalvepage.com
The thinnest base wafers are those produced for the OC44 and OC45.These wafers are only 100 µm thick - a tenth of a millimetre. At this still quite early stage in manufacture, the dice are worth more than their weight in gold.

Sound like a lot of money but it´s just 0,05$.  ;D

Nevertheless you are absolutely right. Back in the days it was unthinkable to buy 30k transistors for 500$.
Title: Re: Transistors - die pictures
Post by: Noopy on January 12, 2022, 08:15:16 pm
(https://www.richis-lab.de/images/transistoren/a38x01.jpg)

I don´t know which company has built this BDY92. The marking looks a little like Philips. What is your opinion?

The BDY92 isolates 60V and can conduct 10A (15A peak). It has a "very high" transition frequency: 70MHz.


(https://www.richis-lab.de/images/transistoren/a38x02.jpg)

(https://www.richis-lab.de/images/transistoren/a38x03.jpg)

Some white potting is protecting the die.


(https://www.richis-lab.de/images/transistoren/a38x04.jpg)

The die is soldered on a round plate.


(https://www.richis-lab.de/images/transistoren/a38x05.jpg)

(https://www.richis-lab.de/images/transistoren/a38x06.jpg)

The edge length of the die is 3,1mm. The structure of the metal layer is interesting. I assume it shall distribute the current as good as possible while providing a low inductance.


(https://www.richis-lab.de/images/transistoren/a38x09.jpg)

The base emitter junction is near the emitter. I don´t know why there are two boundaries.  :-//


(https://www.richis-lab.de/images/transistoren/a38x08.jpg)

Driving the transistor into base-emitter-breakdown we can see the base emitter junction is near the emitter (-7,5V, 1A).


(https://www.richis-lab.de/images/transistoren/a38x10.jpg)

That doesn´t look good. A production problem? A damage caused by the bonding process?


(https://www.richis-lab.de/images/transistoren/a38x07.jpg)

And another artifact...


https://www.richis-lab.de/Bipolar89.htm (https://www.richis-lab.de/Bipolar89.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on January 12, 2022, 08:18:29 pm
Oh cool, a log periodic sort of interdigitation!  With fT of that I would expect perforated emitter, but there you have it.

Tim
Title: Re: Transistors - die pictures
Post by: David Hess on January 12, 2022, 08:51:14 pm
That layout equalizes the emitter resistance to the far points of the emitter.
Title: Re: Transistors - die pictures
Post by: Noopy on January 13, 2022, 09:29:53 pm
That layout equalizes the emitter resistance to the far points of the emitter.

But compared to for example the KD616 the layout ensures a low inductance too:

(https://www.richis-lab.de/images/transistoren/a36x07.jpg)

Title: Re: Transistors - die pictures
Post by: Noopy on January 16, 2022, 04:21:40 am
(https://www.richis-lab.de/images/transistoren/a39x01.jpg)

Sescosem 391HT2 - You don´t find any information about this transistors. It is said to be similar to the BDY25: 140V, 6A, 88W, 10MHz


(https://www.richis-lab.de/images/transistoren/a39x02.jpg)

(https://www.richis-lab.de/images/transistoren/a39x03.jpg)

There is a big heatspreader.
The emitter potential is brought to the die with two bondwires.


(https://www.richis-lab.de/images/transistoren/a39x04.jpg)

The heatspreader is probably made out of copper. In some places it wasn´t coated probably and you can still see it.


(https://www.richis-lab.de/images/transistoren/a39x05.jpg)

(https://www.richis-lab.de/images/transistoren/a39x06.jpg)

The architecture is unusual. The inner contact is the base not the emitter and because of that the inner metal layer was made quite thin.
It seems like the die was broken out of the wafer. You can see the rough edges.


(https://www.richis-lab.de/images/transistoren/a39x07.jpg)

(https://www.richis-lab.de/images/transistoren/a39x08.jpg)

The base metal is smoother than the emitter metal. There are three edges between base and emitter. The outer two are probably the openings in the isolating SiO2. The inner one is the junction.


(https://www.richis-lab.de/images/transistoren/a39x09.jpg)

The base emitter breakdown voltage is quite high: -15V. The datasheet of the BDY25 states -10V.
A nice uniform glowing...  :)


https://www.richis-lab.de/Bipolar90.htm (https://www.richis-lab.de/Bipolar90.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 23, 2022, 09:38:24 pm
(https://www.richis-lab.de/images/transistoren/a40x01.jpg)

Just a small signal transistor, a SC206 built in the Halbleiterwerk Frankfurt Oder.
15V, 100mA, 200mW, 300MHz


(https://www.richis-lab.de/images/transistoren/a40x02.jpg)

The naming is a little strange. S stands for silicon. Since they didn´t package germanium transistors in plastic packages the S is omitted. They omitted the 2 too and so there is just a C06.  :-//

The transistors were binned by hfe. That´s the E in the upper left corner. They sold B (28-71) - F (450-1120). C is a very short datecode.


(https://www.richis-lab.de/images/transistoren/a40x04.jpg)

(https://www.richis-lab.de/images/transistoren/a40x03.jpg)

The edge length of the die is 0,5mm. It is quite similar to the SF137 (https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)).


https://www.richis-lab.de/Bipolar91.htm (https://www.richis-lab.de/Bipolar91.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 27, 2022, 07:36:29 pm
(https://www.richis-lab.de/images/transistoren/a41x01.jpg)

Sescosem BDX18, a PNP transistor conducting up to 15A with a Vce of 60V. ft is 4MHz. The package can dissipate up to 117W.


(https://www.richis-lab.de/images/transistoren/a41x02.jpg)

(https://www.richis-lab.de/images/transistoren/a41x03.jpg)

The die is placed on a big heatspreader and potted.


(https://www.richis-lab.de/images/transistoren/a41x04.jpg)

(https://www.richis-lab.de/images/transistoren/a41x05.jpg)

The potting is really hard to remove. It´s a MESA transistor.


(https://www.richis-lab.de/images/transistoren/a41x06.jpg)

In the lower left corner there is a strange discoloration.  :-//


https://www.richis-lab.de/Bipolar92.htm (https://www.richis-lab.de/Bipolar92.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: doktor pyta on January 29, 2022, 12:17:32 pm
Just found this.
[attachimg=1]
Title: Re: Transistors - die pictures
Post by: Noopy on January 29, 2022, 12:43:02 pm
Just found this.
(Attachment Link)

Sounds interesting!
Kind of an early High-Power-2N3375 (https://www.richis-lab.de/Bipolar56.htm (https://www.richis-lab.de/Bipolar56.htm))  8)
Title: Re: Transistors - die pictures
Post by: Noopy on February 03, 2022, 08:12:48 pm
(https://www.richis-lab.de/images/transistoren/a42x01.jpg)

(https://www.richis-lab.de/images/transistoren/a42x02.jpg)

One more Miniplast-Transistor built by the Halbleiterwerk Frankfurt Oder. The SF216 is specified for high frequency amplifiers and oscillators up to 100MHz. Compared to the SC206 (https://www.richis-lab.de/Bipolar91.htm (https://www.richis-lab.de/Bipolar91.htm)) the SF216 offers a noticeably higher reverse voltage of 33V. The maximum permissible collector current is 100mA. The cutoff frequency is specified with 350MHz. The D in the upper left corner stands for a hfe between 112 and 280.


(https://www.richis-lab.de/images/transistoren/a42x03.jpg)

(https://www.richis-lab.de/images/transistoren/a42x04.jpg)

The edge length of the dies is 0,5mm. The structures are quite similar to the SC206 (https://www.richis-lab.de/Bipolar91.htm (https://www.richis-lab.de/Bipolar91.htm)), but in fact they are a bit closer to the SF137 (https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)). In the left lower corner there is a pattern to check the mask alignment.


https://www.richis-lab.de/Bipolar93.htm (https://www.richis-lab.de/Bipolar93.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on February 03, 2022, 10:18:34 pm
I would like to see what a Zetex "super e-line" transistor looks like.  Other manufacturers now make them as low saturation voltage and high current gain parts.
Title: Re: Transistors - die pictures
Post by: Noopy on February 04, 2022, 05:20:56 am
I would like to see what a Zetex "super e-line" transistor looks like.  Other manufacturers now make them as low saturation voltage and high current gain parts.

I will put it on the list.  :-+
Title: Re: Transistors - die pictures
Post by: floobydust on February 04, 2022, 08:54:09 pm
ZTX689B (https://www.diodes.com/assets/Datasheets/ZTX689B.pdf) and ZTX851 are popular not as a medium power transistor, but for low noise audio preamplifiers and they have a low rbb'. The die would be very interesting to see.
Title: Re: Transistors - die pictures
Post by: Noopy on February 04, 2022, 09:00:42 pm
ZTX689B (https://www.diodes.com/assets/Datasheets/ZTX689B.pdf) and ZTX851 are popular not as a medium power transistor, but for low noise audio preamplifiers and they have a low rbb'. The die would be very interesting to see.

 :-+
Title: Re: Transistors - die pictures
Post by: David Hess on February 05, 2022, 01:38:17 am
ZTX689B (https://www.diodes.com/assets/Datasheets/ZTX689B.pdf) and ZTX851 are popular not as a medium power transistor, but for low noise audio preamplifiers and they have a low rbb'. The die would be very interesting to see.

All of the "super e-line" style transistors should have low base spreading resistance.

The way I remember it, Zetex bought obsolete IC fabrication equipment which was still higher performance than what was being used for bipolar power transistors, so they were able to take advantage of an advanced design, but it was never clear to me what was actually different about their transistors.  I do not think they are just another perforated emitter design.
Title: Re: Transistors - die pictures
Post by: Noopy on February 05, 2022, 07:49:14 pm
(https://www.richis-lab.de/images/transistoren/a43x01.jpg)

Tesla OC26, a germanium transistor supplying you with 32V, 3,5A, 12,5W and a hfe of 20-75.
The OC27 is specified with a hfe of 60-180. The other characteristics are the same as for the OC26. These transistors were probably binned.


(https://www.richis-lab.de/images/transistoren/a43x02.jpg)

The thickness of the base plate is 3,1mm!  :o


(https://www.richis-lab.de/images/transistoren/a43x03.jpg)

The small cylinder probably dehumidifies the package.


(https://www.richis-lab.de/images/transistoren/a43x04.jpg)

The contacts are metal sheets welded to the pins of the package.


(https://www.richis-lab.de/images/transistoren/a43x05.jpg)

The base metal sheet forms a ring carrying the germanium slice.
It seems like the transistor was coated with some clear varnish.


(https://www.richis-lab.de/images/transistoren/a43x06.jpg)

(https://www.richis-lab.de/images/transistoren/a43x07.jpg)

At the edge the germanium slice is round about 200µm thick.


(https://www.richis-lab.de/images/transistoren/a43x08.jpg)

Here you can see the socket on which the transistor is mounted.


https://www.richis-lab.de/Bipolar94.htm (https://www.richis-lab.de/Bipolar94.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 06, 2022, 04:29:40 am
(https://www.richis-lab.de/images/transistoren/a39x01.jpg)

Sescosem 391HT2 - You don´t find any information about this transistors. It is said to be similar to the BDY25: 140V, 6A, 88W, 10MHz

[...]

https://www.richis-lab.de/Bipolar90.htm (https://www.richis-lab.de/Bipolar90.htm)

Someone told me he knows the 391HT2 as a soviet transistor (it would be a 391NT2).
He had a picture of the 391HT2 with a Russian manufacturer logo.

Sescosem naming a transistor like a soviet transistor? I have never seen something like that.
A Russian manufacturer naming a transistor like a Sescosem transistor? I can´t believe that too.

What is your opinion?
Title: Re: Transistors - die pictures
Post by: Ground_Loop on February 06, 2022, 03:05:42 pm
Not as good as most here, but thought this was really interesting. The attached was removed from a failed variable frequency drive. This wafer contains 7 IGBTs (rated 1200 volts and 18 amps each) with protection diodes. Six of them are the output bridge to the motor and the seventh is a brake resistor chopper. Also on the wafer are the six diodes that rectify the incoming 3 phase 480VAC.  The small device on the far right is the temperature feedback.  The six black IGBTs suffered catastrophic failure due to sudden power disconnect combined with improper line conditioning. 

Attachments between the device and the circuit board are through a block of pogo pins bolted to the top. The bolt connection also serves to attach the wafer against the heat sink. The whole wafer is coated in silicone gel that the pogo pins penetrate for connections. The silicone gel was tough to remove. Seems that nothing is a good solvent for it. Persistence with 3 in 1 oil and an acid brush removed enough for the picture.

[attach=1]
Title: Re: Transistors - die pictures
Post by: Noopy on February 07, 2022, 03:36:22 pm
 :-+
Silicone gel potting is a pain in the ass!  :rant:
Title: Re: Transistors - die pictures
Post by: Noopy on February 18, 2022, 04:24:00 am
(https://www.richis-lab.de/images/transistoren/a44x01.jpg)

Tungsram ASZ1017, a Germanium based PNP power transistor.

There are four transistors: ASZ1015, ASZ1016, ASZ1017 and ASZ1018. All of them with a maximum power dissipation of 20W, a maximum collector current of 6A and a ft of 250kHz. Vce of the ASZ1015 is 60V. The others are specified with 32V to 48V depending on the datasheet you look at. The transistors have different amplification factors. The ASZ1017 is specified with 25 to 75.

It seems like ASZ1015 - ASZ1018 are worse variants of the ASZ15 - ASZ18. The ASZ15 - ASZ18 can conduct up to 8A and the maximum power dissipation is 30W.


(https://www.richis-lab.de/images/transistoren/a44x02.jpg)

The base plate of the transistor is quite thick.


(https://www.richis-lab.de/images/transistoren/a44x03.jpg)

There is a notch in the base plate.


(https://www.richis-lab.de/images/transistoren/a44x04.jpg)

The package is full with a dehumidifier powder.


(https://www.richis-lab.de/images/transistoren/a44x05.jpg)

(https://www.richis-lab.de/images/transistoren/a44x06.jpg)

(https://www.richis-lab.de/images/transistoren/a44x07.jpg)

The setup is quite similar to the other transistors we have seen. Base and emitter contact was one sheet in the beginning. In contrast to the other transistors here the sheet was cutted mechanically.


(https://www.richis-lab.de/images/transistoren/a44x08.jpg)

(https://www.richis-lab.de/images/transistoren/a44x09.jpg)

Nothing too special...


https://www.richis-lab.de/Bipolar95.htm (https://www.richis-lab.de/Bipolar95.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 21, 2022, 07:34:33 am
A small update to the Tungsram ASZ1017:


(https://www.richis-lab.de/images/transistoren/a44x10.jpg)

(https://www.richis-lab.de/images/transistoren/a44x11.jpg)

The case is made of plated copper. The dome on which the germanium plate is placed was not plated.

In the second picture you can see that the germanium plate is a square. It´s round about 0,2mm thick.


https://www.richis-lab.de/Bipolar95.htm#Update (https://www.richis-lab.de/Bipolar95.htm#Update)

 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on February 21, 2022, 02:43:27 pm

OMG your pictures keep getting more amazing!  :D
Title: Re: Transistors - die pictures
Post by: Noopy on February 25, 2022, 11:16:28 am
(https://www.richis-lab.de/images/transistoren/a45x01.jpg)

RCA 2N3773, a very powerful transistor (140V, 16A/30A, 150W).

There is a smaller brother (2N4348) and a bigger brother (2N6259). The latter with 170V/250W.

Datasheet states a hfe of 15-60.


(https://www.richis-lab.de/images/transistoren/a45x02.jpg)

(https://www.richis-lab.de/images/transistoren/a45x03.jpg)

A big heatspreader and quite big contact sheets compared to for example the 2N3055H (https://www.richis-lab.de/2N3055_05.htm (https://www.richis-lab.de/2N3055_05.htm)).


(https://www.richis-lab.de/images/transistoren/a45x04.jpg)

(https://www.richis-lab.de/images/transistoren/a45x05.jpg)

The edge length of the die is 6,3mm to make the high current rating possible.


(https://www.richis-lab.de/images/transistoren/a45x06.jpg)

(https://www.richis-lab.de/images/transistoren/a45x07.jpg)

It´s a hometaxial transistor as it is explained with the "2N3055 (1966)" in more detail: https://www.richis-lab.de/2N3055_08.htm (https://www.richis-lab.de/2N3055_08.htm)


(https://www.richis-lab.de/images/transistoren/a45x08.jpg)

Typical for a hometaxial transistor the base emitter breakdown occurs quite late: -34V

At 1A the current distribution is very uneven.


(https://www.richis-lab.de/images/transistoren/a45x10.jpg)

Increasing the current to 3A (>100W of power) kills the junction.

I have done a video: https://www.richis-lab.de/images/transistoren/a45x09.mp4 (https://www.richis-lab.de/images/transistoren/a45x09.mp4)  >:D


(https://www.richis-lab.de/images/transistoren/a45x11.jpg)

 >:D


https://www.richis-lab.de/Bipolar96.htm (https://www.richis-lab.de/Bipolar96.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 07, 2022, 04:51:22 am
(https://www.richis-lab.de/images/transistoren/a46x01.jpg)

2SD70 is a power transistor built by NEC. We don´t see "NEC" on the package but the special construction makes it likely that it is really built by NEC.

There is few information about the transistor. Looks like it can conduct 2A and isolate 25V. The TO-66 package allows you to dissipate up to 15W.


(https://www.richis-lab.de/images/transistoren/a46x02.jpg)

(https://www.richis-lab.de/images/transistoren/a46x03.jpg)

That´s a strange construction...


(https://www.richis-lab.de/images/transistoren/a46x04.jpg)

(https://www.richis-lab.de/images/transistoren/a46x05.jpg)

There are brackets welded on the pins which makes it easier to bond the connection wires.


(https://www.richis-lab.de/images/transistoren/a46x06.jpg)

(https://www.richis-lab.de/images/transistoren/a46x07.jpg)

The die looks quite normal (1,2mm x 1,2mm). You have two base contact areas so you can turn the die 180°.


(https://www.richis-lab.de/images/transistoren/a46x08.jpg)

Nothing special...


(https://www.richis-lab.de/images/transistoren/a46x13.jpg)

But in the upper left corner it looks like the metal migrated a little to the junction or it wasn´t removed properly while manufacturing the transistor.


(https://www.richis-lab.de/images/transistoren/a46x09.jpg)

Base emitter breakdown at -7,5V / 10mA.


(https://www.richis-lab.de/images/transistoren/a46x10.jpg)

100mA - It seems like the "metal problem" doesn´t affect the current distribution.


(https://www.richis-lab.de/images/transistoren/a46x11.jpg)

200mA


(https://www.richis-lab.de/images/transistoren/a46x12.jpg)

500mA


https://www.richis-lab.de/Bipolar97.htm (https://www.richis-lab.de/Bipolar97.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 21, 2022, 04:41:39 am
(https://www.richis-lab.de/images/transistoren/a47x01.jpg)

Hitachi 2SB228, a Ge-Transistor conducting up to 5A with an Vce of 35V. At 25°C it can dissipate up to 50W.


(https://www.richis-lab.de/images/transistoren/a47x02.jpg)

(https://www.richis-lab.de/images/transistoren/a47x03.jpg)

The thickness of the base plate is 1,3mm. There is a circle...


(https://www.richis-lab.de/images/transistoren/a47x04.jpg)

There is some dehumidifier.


(https://www.richis-lab.de/images/transistoren/a47x05.jpg)

The transistor itself is placed on a socket as we have seen it a lot.

There is an opaque protection paint.


(https://www.richis-lab.de/images/transistoren/a47x06.jpg)

(https://www.richis-lab.de/images/transistoren/a47x07.jpg)

Most of the germanium transistors use solder to connect emitter and collector and in addition to p-dope the n-doped germanium disc.

Here the connector wire of the emitter is soldered to a round metal plate. The p-doping has to be under this metal plate.



(https://www.richis-lab.de/images/transistoren/a48x01.jpg)

Now that is another Hitachi 2SB228.


(https://www.richis-lab.de/images/transistoren/a48x02.jpg)

(https://www.richis-lab.de/images/transistoren/a48x03.jpg)

But the base plate is really thin (0,85mm)!


(https://www.richis-lab.de/images/transistoren/a48x04.jpg)

(https://www.richis-lab.de/images/transistoren/a48x05.jpg)

(https://www.richis-lab.de/images/transistoren/a48x06.jpg)

Now that´s the cause for the thinner base plate. Hitachi has put a massive heatspreader into the package. There is hardly room left for the dehumidifier.

This transistor is probably as good as the upper one but if you look at it from the outside it looks like a worse one.


(https://www.richis-lab.de/images/transistoren/a48x07.jpg)

The protection paint looks a little worse than in the first transistor.


https://www.richis-lab.de/Bipolar98.htm (https://www.richis-lab.de/Bipolar98.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Richard576 on March 25, 2022, 12:12:12 am
I have been following your topic for a while, very interesting to the point that a few days ago i decided to open a old ussr transistor which came from my broken old 70's oscilloscope, i guess it is germanium, the writing on it is cyrillic it is to-3 size but without the mounting tabs, it has been standing in sight on a ledge for years and a few days ago i was bored to the point i thought "now is the time, i wanna see whats inside", just like you  :-+

Opening it i found the white powder which you refer to as dehumidifier which makes sense if there is a little bit of it in a transistor
On the other hand: mine was completely packed with bright white powder , could that be to transfer heat?, and could that be the dreaded beryllium oxide in powdered form?  :palm:

As you may guess and notice: i am a bit freaked out, i did not expect the white powder as most of the transistors you open do not have it, i have seen one fully packed and the powder looks different to mine, mine is very fine structure like talcum powder en bright white.

I tossed the whole bunch in a box outside, cleaned my workspace until my fingers where raw, showered an hour and washed my clothes 3 times, just to be sure...  ::)

Any thoughts on this?

Richard , netherlands
Title: Re: Transistors - die pictures
Post by: Noopy on March 25, 2022, 04:56:17 am
Hi Richard!

You don't have to worry about that powder. That surely was a dehumidifier.
It would just make no sense to fill a package with BeO powder. The heat transfer through the base plate of the package is quite good. That would be like wrapping a copper busbar with aluminium foil to reduce the resistance.
I'm not even sure if the thermal conductivity of BeO powder is that good.

You are just in danger to damage your clothes by too much washing.  ;)

Greetings,

Richard
Title: Re: Transistors - die pictures
Post by: Richard576 on March 25, 2022, 12:23:54 pm
Hi Richard!

Thank you so much for your answer, this had me spooked , i can breathe again  :-DD :-+

I will hang upside down in my garbage container to get it out if i can find it, i will post some picture if i can.
Do you think the desiccant is something usually in germanium transistors found as i understood these are very susceptible to moisture ingress and damage, the indium solder becomes damaged?
I cant remember a photo of you with a silicium transistor with desiccant inside?

As i am new to this i guessed mine being old it was probably soldered shut and so i tried to heat it hoping the solder would melt, i now know they are probably welded in some form so you need to dremel them open, but in the heating i destroyed the text on it so no idea what type it is/was  :(

Thanks a bunch and i will post some photos soon.
Big kudos for your topic, i find this so interesting and amazing technology  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on March 25, 2022, 06:07:44 pm
There is no passivation on a germanium transistor so they are especially susceptible to moisture. But I don´t know what the precise damage szenario is.

You can find dehumidifier in silicon transistors too: https://www.richis-lab.de/Bipolar31.htm (https://www.richis-lab.de/Bipolar31.htm)
They all have to protect their semiconductor structures. If your passivation is not good enough or your package isn´t tight enough you have to put dehumidifier into the package. If it is really bad even a dehumidifier doesn´t help: https://www.richis-lab.de/Bipolar65.htm (https://www.richis-lab.de/Bipolar65.htm)

Thanks for the positive feedback. I´m planning to open "some" more parts...  ;D :-+
Title: Re: Transistors - die pictures
Post by: Richard576 on March 29, 2022, 12:01:27 am
I understand about passivation but would that be passivation of the metal parts? I guess there is not much point in passivating germanium or silicon?

Anyway, unfortunately i could not retrieve my transistor of the bottom of the garbage can, my girlfriend tossed the contents of the bag-less vacuum cleaner on top of it and i am not looking forward to wonder through a few pounds of vacuum cleaner dust and crap, sorry  :--
It wasn't all that exciting also just a piece of germanium with 2 contact points on it.

Thanks for now, looking forward to the opening of other packages  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on March 29, 2022, 06:11:10 am
I understand about passivation but would that be passivation of the metal parts? I guess there is not much point in passivating germanium or silicon?

Especially the semiconductor material has to be protected with a passivation layer!
Back in the days one important step of the manufacturing process was etching the surface of a diode or transistor to get it as clean as possible. (Today "everything is clean all the time".  ;) )
Surface contamination is a critical issue. Very very little contamination can ruin your device. That's why there were MESA transistors and why the best zener diodes are buried.


Anyway, unfortunately i could not retrieve my transistor of the bottom of the garbage can, my girlfriend tossed the contents of the bag-less vacuum cleaner on top of it and i am not looking forward to wonder through a few pounds of vacuum cleaner dust and crap, sorry  :--
It wasn't all that exciting also just a piece of germanium with 2 contact points on it.

Sounds quite normal.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on April 01, 2022, 07:49:55 pm
(https://www.richis-lab.de/images/transistoren/a49x01.jpg)

(https://www.richis-lab.de/images/transistoren/a49x02.jpg)

(https://www.richis-lab.de/images/transistoren/a49x03.jpg)

Now let us take a look into a more up to date transistor! The Fairchild FDMS3602S offers two asymmetric n-channel MOSFETs in a low-profile Power 56 package. The design is optimized for a buck converter. Transistor Q1 is the switching transistor. Q2 is the active rectifier. The integration in a package allows us to keep the traces short that carry switched currents. That reduces losses due to parasitic inductances and EMC problems.

The transistors own significantly different specs. Breakdown voltage is 25 for both transistors. Q1 offers a maximum on resistance of 8.1mΩ. The resistance of Q2 is significantly smaller with a maximum of 3.4mΩ. This is advantageous when the input voltage of a buck regulator is more than twice the output voltage. In this case, Q2 conducts current longer than Q1 and contributes more to the total loss. The datasheet states a permanent current carrying capability of 30A/40A (Q1/Q2, Tc=25°C). Up to 40A/100A are allowed for a short time.

The switching transistor Q1 has a higher impedance, but offers lower capacitances and faster switching. The rise and fall times are typically half those of Q2. This reduces switching losses in Q1 which is loaded with the input voltage.

As being the active rectifier Q2 has a Schottky diode connected in parallel to the intrinsic body diode. The lower forward voltage and smaller reverse capacitance reduce losses in the dead times when both transistors are blocked and in the transition phases. One could use the Schottky diode without driving the transistor. However the datasheet points out that typically for a Schottky diode the reverse current increases sharply with temperature. That can cause problems with the maximum power dissipation of the package. The Schottky diode is not a discrete element, but is located within the PowerTrench MOSFET. Fairchild calls these components SyncFETs.


(https://www.richis-lab.de/images/transistoren/a49x04.jpg)

The transistor Q1 is located on the left leadframe. 15 bondwires connect the top of the transistor (source) with the leadframe in the middle. Q2 is placed here. Source of Q2 is connected with a comb-like sheet metal element. Above this contact sheet you can see the bondwire which connects the gate.


(https://www.richis-lab.de/images/transistoren/a49x05.jpg)

Q1 is 2.1mm x 0.8mm. The source metal layer is divided into two areas.

Vias are visible just at the upper and lower edges of these areas. Most likely the MOSFET consists of many small MOSFET cells as it is common for power MOSFETs (see for example BUK446: https://www.richis-lab.de/FET07.htm (https://www.richis-lab.de/FET07.htm)). It is interesting that vias can just be seen on the sides.

The gate potential arrives in the upper right corner and is distributed over the die with a thin frame structure.


(https://www.richis-lab.de/images/transistoren/a49x06.jpg)

(https://www.richis-lab.de/images/transistoren/a49x07.jpg)

Q2 is 2.5mm x 1.5mm. The contact plate has four contact fingers but just three of them are connected to the die. Apparently this contact element is suitable for contacting wider MOSFETs.

The surface is covered with a protective layer, probably a polyimid. In the middle, at the upper and lower edge thin gate traces can be seen.


https://www.richis-lab.de/FET22.htm (https://www.richis-lab.de/FET22.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 01, 2022, 08:11:25 pm
Cool!  ...Aww, was hoping to see what the schottky structure looks like.  But it's buried under all that metal, of course. ::) Oh well :)

Tim
Title: Re: Transistors - die pictures
Post by: Miyuki on April 03, 2022, 01:42:20 pm
Great work
I just wonder if can be opened some of this integrated high power buck for high power processors
Like for example
TPS546D24A

As they work with huge currents and in single MHz switching frequencies
Title: Re: Transistors - die pictures
Post by: Noopy on April 03, 2022, 05:39:31 pm
Thanks!  :)

You are right the TPS546D24A sounds interesting! I will put it on my (long) list.  :-+

Also on my list is a LT8638. It gives you just 10A/12A but integrated in the LQFN package there are one 100nF and two 10nF capacitors!  :o
Either they integrated MLCCs or there are Silicon Capacitors in the package.
Title: Re: Transistors - die pictures
Post by: Noopy on April 05, 2022, 07:36:09 pm
(https://www.richis-lab.de/images/transistoren/a50x01.jpg)

(https://www.richis-lab.de/images/transistoren/a50x02.jpg)

Who knows TET (Tallinna Elektrotehnika Tehas)? It´s an Estonian semiconductor manufacturer. TET Estel still produces semiconductors and power electronic devices.

Here we have a power thyristor built by TET, a T62-160-10.


(https://www.richis-lab.de/images/transistoren/a50x03.jpg)

The name of the device is written onto the package by hand.


(https://www.richis-lab.de/images/transistoren/a50x04.jpg)

In the "Applikative Informationen" of the VEB Applikationszentrum Elektronik Berlin 2/1984 you can find a explanation for the naming.

T stands for a thyristor, sometimes you have a second letter for special types.
62 is the thyristor familiy.
160 stands for 160A
10 stands for a blocking voltage of 1000V
The other numbers are probably dynamic parameter like the critical voltage slew rate.


(https://www.richis-lab.de/images/transistoren/a50x06.jpg)

The ground plate is 65mm in diameter and has a height of 7mm. The cylinder wall is 3mm thick.


(https://www.richis-lab.de/images/transistoren/a50x07.jpg)

A green glass like material closes the package around the cathode contact.


(https://www.richis-lab.de/images/transistoren/a50x08.jpg)

The base plate is made of copper.


(https://www.richis-lab.de/images/transistoren/a50x09.jpg)

The thyristor itself is 3cm in diameter and protected with a red coating.

The cathode wire is crimped in a short wire-end sleeve that is soldered onto the thyristor die.


(https://www.richis-lab.de/images/transistoren/a50x10.jpg)

The thyristor die is placed on a disc that is soldered to the package.


(https://www.richis-lab.de/images/transistoren/a50x11.jpg)

The cathode contact is quite high, probably to get it mechanical stable.


(https://www.richis-lab.de/images/transistoren/a50x15.jpg)

(https://www.richis-lab.de/images/transistoren/a50x12.jpg)

At some places around the cathode contact there are dark areas that possibly contain the cathode doping.  :-//

There is a solder ring around the cathode, perhaps to distribute the gate potential? Interestingly the solder ring doesn´t connect to the gate contact.


(https://www.richis-lab.de/images/transistoren/a50x13.jpg)

(https://www.richis-lab.de/images/transistoren/a50x14.jpg)

It looks like the die was processed two times to flatten it to the edge. You can see typical etch structures.


https://www.richis-lab.de/Bipolar99.htm (https://www.richis-lab.de/Bipolar99.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 06, 2022, 03:28:12 am
It looks like the name of the thyristor is TB2-160-10.
If you compare the "first 6" with the second 6 the first one is more edged like a cyrillian B.
B then stands for a  fast transistor.

I thought is could be a T62 because you still can buy T62 thyristors but you don´t find much information about TB2 thyristors.

I have changed the article.  :-/O
Title: Re: Transistors - die pictures
Post by: MegaVolt on April 07, 2022, 08:07:49 am
Yes, it looks like ТБ2-160
Here is the information:
https://eandc.ru/catalog/detail.php?ID=15835
Title: Re: Transistors - die pictures
Post by: Noopy on April 07, 2022, 10:59:26 am
Yeah, that looks like a brother!  :-+

Thanks!
Title: Re: Transistors - die pictures
Post by: Noopy on April 11, 2022, 08:55:10 am
(https://www.richis-lab.de/images/transistoren/a51x01.jpg)

One more Tesla power transistor. The KD617 is the complementary PNP to the KD607. The specs are the same: It can isolate 80V, conduct 10A and ft is 2MHz.


(https://www.richis-lab.de/images/transistoren/a51x04.jpg)

On the backside you can see the circle of the copper cylinder in the base plate that conducts the heat very efficient.


(https://www.richis-lab.de/images/transistoren/a51x02.jpg)

(https://www.richis-lab.de/images/transistoren/a51x03.jpg)

We have seen the red potting a lot in the Tesla transistors.


(https://www.richis-lab.de/images/transistoren/a51x05.jpg)

(https://www.richis-lab.de/images/transistoren/a51x06.jpg)

(https://www.richis-lab.de/images/transistoren/a51x07.jpg)

The edge length of the die is 4,5mm. That´s the same size as the KD616 (https://www.richis-lab.de/Bipolar87.htm (https://www.richis-lab.de/Bipolar87.htm)). The KD615, the KD616 and the KD617 are probably the same transistors just binned with respect to their voltage rating.


(https://www.richis-lab.de/images/transistoren/a51x08.jpg)

Here you can see the base emitter junction. The edges around the metal structures are the edges of the contact vias.


(https://www.richis-lab.de/images/transistoren/a51x09.jpg)

(https://www.richis-lab.de/images/transistoren/a51x11.jpg)

(https://www.richis-lab.de/images/transistoren/a51x10.jpg)

The MESA structure is surprisingly unsteady. At the edge of the transistor there are quite deep and unsteady pits. It looks like the etching process didn´t work too well.


https://www.richis-lab.de/BipolarA01.htm (https://www.richis-lab.de/BipolarA01.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 22, 2022, 07:24:27 pm
(https://www.richis-lab.de/images/transistoren/a50x01.jpg)

https://www.richis-lab.de/Bipolar99.htm (https://www.richis-lab.de/Bipolar99.htm)


I just found a datecode on the cable shoe:


(https://www.richis-lab.de/images/transistoren/a50x16.jpg)
Title: Re: Transistors - die pictures
Post by: Noopy on April 23, 2022, 08:52:19 pm
(https://www.richis-lab.de/images/transistoren/a52x01.jpg)

(https://www.richis-lab.de/images/transistoren/a52x02.jpg)

The SF123 (TO-5) is a transistor built by the Halbleiterwerk Frankfurt Oder. DO stands for a production in April 1974. The maximum collector emitter voltage is 40V. The SF122 and the SF121 appear to be poorer grades. They offer the same specifications, but Vce is just 30V and 20V. The SF123 allows 100mA continuously and up to 600mW.

The datasheet recommends the SF123 for LF and RF applications. However, the cutoff frequency is not excessive with typically 130MHz, minimum 60MHz. The SF137 (https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)) with its cutoff frequency of at least 300MHz is more suitable for high frequency applications.

As with the SF137 the current gain spread was initially very high. Values between 18 and 1120 were allowed. The transistors were binned in six groups. The SF123D offers a current gain of 112 to 280. This fits with the fact that from 1970 on just D and E types were produced.

The SF123 is a simple planar transistor. You can see that looking at the collector emitter saturation voltage. The transistor is manufactured on a n-doped substrate that forms the collector. In this substrate you dope base and emitter areas. The datasheet specifies a maximum Vcesat of 1V. The SF137 on the other hand is a planar epitaxial transistor. The substrate is heavily n-doped, which guarantees a low collector resistance. However, the collector region itself must not be doped too intense, otherwise the blocking voltage will be very low. For this reason, a thin, less heavily doped collector region is epitaxially deposited on the highly doped substrate. The result is a maximum saturation voltage of just 0.3V.


(https://www.richis-lab.de/images/transistoren/a52x03.jpg)

(https://www.richis-lab.de/images/transistoren/a52x05.jpg)

(https://www.richis-lab.de/images/transistoren/a52x04.jpg)

With an edge length of 1mm the die is twice as big as the SF137.


(https://www.richis-lab.de/images/transistoren/a52x06.jpg)

And some light...  8)
-8V 10mA


(https://www.richis-lab.de/images/transistoren/a52x07.jpg)

20mA


(https://www.richis-lab.de/images/transistoren/a52x08.jpg)

50mA


(https://www.richis-lab.de/images/transistoren/a52x09.jpg)

80mA


(https://www.richis-lab.de/images/transistoren/a52x10.jpg)

400mA


https://www.richis-lab.de/BipolarA02.htm (https://www.richis-lab.de/BipolarA02.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: mawyatt on April 24, 2022, 03:10:35 pm
This looks like an old 2N706 transistor that wayback was somewhat famous for the avalanche mode relaxation oscillator behavior.

As always, nice image, and amazed at how many of these you produce :-+

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on April 26, 2022, 07:51:29 pm
As always, nice image, and amazed at how many of these you produce :-+

Thanks! I do my very best to reduce the stockpile of interesting parts.  ;D



(https://www.richis-lab.de/images/transistoren/a53x01.jpg)

(https://www.richis-lab.de/images/transistoren/a53x02.jpg)

(https://www.richis-lab.de/images/transistoren/a53x03.jpg)

BD1428 - can anybody tell me who manufactured this dual transistor?

There is a notice written by myself stating that the BD1428 was built by the russian manufacturer Istok. Unfortunately I wasn´t able to find any proof for this statement and I found no hint were I got this information from.  :-//

It looks like the BD1428 has been manufactured in 1969.


(https://www.richis-lab.de/images/transistoren/a53x04.jpg)

(https://www.richis-lab.de/images/transistoren/a53x05.jpg)

(https://www.richis-lab.de/images/transistoren/a53x06.jpg)

(https://www.richis-lab.de/images/transistoren/a53x07.jpg)

The die is 0,55mm x 0,43mm and it is surprisingly dirty.

The two transistors are isolated with a structure formed like an eight. Like in the К1HT291Б (https://www.richis-lab.de/Bipolar71.htm (https://www.richis-lab.de/Bipolar71.htm)) you can see no buried collector contact. Instead of this buried collector contact the metal contact is designed around half of the transistor.


https://www.richis-lab.de/BipolarA03.htm (https://www.richis-lab.de/BipolarA03.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: jpe on April 29, 2022, 02:33:05 am
I would like to see what a Zetex "super e-line" transistor looks like.  Other manufacturers now make them as low saturation voltage and high current gain parts.

Had a spare ZTX851, unfortunately the die cracked while decapping but most of it is still intact.

Die is aprox 1780x1780µm and has a perforated emitter design - layout looks very similar to the 2STD1665 (https://zeptobars.com/en/read/ST-2STD1665-NPN-BJT).

(https://i.imgur.com/WnBH3Ad.jpg)

(https://i.imgur.com/OgFf0Is.jpg)

(https://i.imgur.com/6jMWrnA.jpg)
Title: Re: Transistors - die pictures
Post by: David Hess on April 29, 2022, 11:26:30 pm
I would like to see what a Zetex "super e-line" transistor looks like.  Other manufacturers now make them as low saturation voltage and high current gain parts.

Had a spare ZTX851, unfortunately the die cracked while decapping but most of it is still intact.

Die is aprox 1780x1780µm and has a perforated emitter design - layout looks very similar to the 2STD1665 (https://zeptobars.com/en/read/ST-2STD1665-NPN-BJT).

So it is "just" a perforated emitter design.  I thought there must be more to it, and maybe there is.  The story I remember is that Zetex bought old IC fabrication equipment which supported a much finer feature size than the equipment normally used for discrete transistor production.  It looks like what they did is take the perforated or ring emitter design and scale it down to smaller transistors.  For a short time Zetex made a larger TO-225 or TO-220 part but I never got any.

Was a die shot of the D44/D45 series TO-220 ring emitter transistors posted?  A comparison to get an idea of the difference in feature size could be informative.

While not advertised as such and as might be expected from their construction, these Zetex transistors apparently have very low base spreading resistance leading to low noise.  Monolithic transistors built in an IC process like the LM394 and MAT series also have low base spreading resistance for low noise, which makes me wonder how similar their construction is.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 29, 2022, 11:33:24 pm
I wonder how much internal structure is hidden under the metallization, or what the diffusions are like.

I wouldn't think perf emitter is quite a sufficient explanation, as the low Vce(sat) and high inverted hFE of these types isn't common to the similar types of power transistors as far as I know.

Is the base layer unusually thin (and fT and hFE maintained by the fine interdigitation)?  Hm, I forget if Early effect is especially worse on these.

Tim
Title: Re: Transistors - die pictures
Post by: David Hess on April 29, 2022, 11:37:49 pm
Hm, I forget if Early effect is especially worse on these.

I never measured it quantitatively, but it looked better on the curve tracer, and of course the saturation curve is very "hard" with an abrupt transition.  I never saw them used for precision analog applications though, with the exception being where low noise was desired and now they are apparently quite popular for that.

Is the base layer unusually thin (and fT and hFE maintained by the fine interdigitation)?

Would that result in higher junction capacitance?  I have not studied it in detail, but I think they suffer from much higher capacitance limiting dynamic performance.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on April 30, 2022, 01:31:42 am
They'd be great for analog switches, but the days of discrete or hybrid ADC designs are looooong gone, so... :-DD

Capacitance is fairly high but I always figured that was simply because the junction is wider; the Ccb / Ic(max) is fairly typical, AFAIK.

Doping or abruptness definitely isn't anything special, Veb is normal.  And given the high inverted hFE, the ratio of E/C doping densities can't be extreme either.

Tim
Title: Re: Transistors - die pictures
Post by: jpe on April 30, 2022, 11:33:43 pm
A look under the metallization

(https://i.imgur.com/grXAUnm.jpg)
Title: Re: Transistors - die pictures
Post by: Noopy on May 11, 2022, 03:59:14 pm
(https://www.richis-lab.de/images/transistoren/a54x01.jpg)

You need more power? Take a Infineon EconoPACK!

The FS300R12OE4 contains a B6 bridge using the IGBT4 generation.

There are mounting holes to screw your gate driver board directly on top of the module. The low power pins are pressfit pins.

These modules are used a lot in motor inverters, photovoltaic inverters or USV.

(Thanks to capt bullshot!)


(https://www.richis-lab.de/images/transistoren/a54x04.jpg)

The name FS300R12OE4 contains a lot of information:
- FS: sixpack configuration
- 300: 300A maximum collector current
- R: reverse conducting
- 12: 1200V maximum Vce
- O: mechanical design
- E4: fast Trench-IGBTs with low Vcesat

The dot matrix code contains the number 00009 034011 80690664 1403
- 00009 is the Module Serial Number
- 034011 is the Module Material Number
- 80690664 is the Production Order Number
- 1403 is the date code
(datasheet information)

Datasheet tells you some more:
1200V is the maximum Vce. The isolation test voltage is 2,5kV. 300A are ok if the case is at 100°C. At 25°C a current of 460A is allowed. The package can dissipate up to 1650W. The thermal resistance between one IGBT and the case is just 0,091K/W (with isolation between IGBT and case!). Maximum peak current (1ms) is 600A. The module limits the short circuit current at 1200A (800V). At 150°C and 300A of collector current Vcesat is 2,05V. At 1200V the residual current can be up to 3mA.

Gate-Emitter-Voltage has to stay within +/-20V. At 15V the gate charge is 2,25µC. Datasheet tells us there is a integrated gate resistor with 2,5Ω. Input capacitance is 18,5nF. Reverse transfer capacitance is 1,05nF.

The freewheeling diode can conduct 300A too. At 300A and 25°C the forward voltage is 1,65V typ, 2,10V max.


(https://www.richis-lab.de/images/transistoren/a54x07.jpg)

The datasheet shows the wiring of the module. Six IGBTs are connected as a B6 bridge. Parallel to the transistors are free-wheeling diodes. An NTC enables a temperature measurement.

Besides the absolutely necessary contacts the module has some auxiliary contacts. Each gate contact has a so-called auxiliary emitter. With this auxiliary emitter a clean gate-emitter voltage can be set which is just slightly distorted by the load current.

Further auxiliary contacts are located at the collectors of the upper transistors. Since the positive supply potential is present there it is possible to supply the gate driver circuit without much effort. An important function for the module itself is the so-called desaturation detection. This monitors the voltage drop across the IGBT. In the event of a problematically high current flow, the transistor leaves the saturation area and the voltage drop increases. If such a voltage rise occurs, the transistor can be shut down before damage occurs. The collectors of the lower transistors are accessible via the auxiliary emitters of the upper transistors.


(https://www.richis-lab.de/images/transistoren/a54x02.jpg)

(https://www.richis-lab.de/images/transistoren/a54x03.jpg)

Quite a massive cooling plate.


(https://www.richis-lab.de/images/transistoren/a54x08.jpg)

There are eight hooks. Bending the hooks you can remove the top cover.


(https://www.richis-lab.de/images/transistoren/a54x09.jpg)

PBT GF30, Polybutylenterephthalat with 30% of fiberglass. PBT is similar to PET.


(https://www.richis-lab.de/images/transistoren/a54x10.jpg)

(https://www.richis-lab.de/images/transistoren/a54x11.jpg)

The active parts and the bondwires are protected with a transparent silicone gel potting.


(https://www.richis-lab.de/images/transistoren/a54x12.jpg)

The three phases are clearly visible. Each phase is supplied individually via the two lower screw-on points. The two upper screw contacts represent the output of each push-pull stage.

On the left side of each phase the low-side transistors are controlled. The high-side transistors are controlled on the right side. Furthermore, DC-, DC+ and AC can be connected via press-fit contacts at each phase. On the right phase there are the contacts of the NTC, which is used for temperature measurement.


(https://www.richis-lab.de/images/transistoren/a54x14.jpg)

This is a high power contact! Datasheet states a lead resistance of 1,1mΩ.


(https://www.richis-lab.de/images/transistoren/a54x16.jpg)

(https://www.richis-lab.de/images/transistoren/a54x15.jpg)

(https://www.richis-lab.de/images/transistoren/a54x13.jpg)

The NTC is packaged in a MELF housing. The temperature measurement is connected just at one phase, but the NTCs are present in each phase. In this way, each DBC can be set up in the same way. The temperature measurement just serves to check the temperature of the module approximately, local hot spots cannot be detected.


(https://www.richis-lab.de/images/transistoren/a54x17.jpg)

(https://www.richis-lab.de/images/transistoren/a54x18.jpg)

Each phase is composed of a lowside block (left) and a highside block (right). Lowside and highside each consist of three IGBT dies and three diode dies.

The arrangement of the components must meet many requirements. One important consideration is leakage inductance, which the datasheet specifies as typically 20nH. An inductance as low as possible reduces the switching losses. For this reason, among others, the DC link capacitor is usually directly and massively connected to the module. Another important point is a uniform current distribution across the individual transistors and, in the case of transient processes, also a uniform voltage distribution. Furthermore, the semiconductors have to be cooled reasonably evenly.


(https://www.richis-lab.de/images/transistoren/a54x20.jpg)

Here you can see the DBC a little better. The ceramic is aluminium oxide.


(...)

Title: Re: Transistors - die pictures
Post by: Noopy on May 11, 2022, 04:00:19 pm
(https://www.richis-lab.de/images/transistoren/a54x19.jpg)

Six bonding wires connect the emitters of each IGBTs with the free-wheeling diodes and the output or DC-.

The free-wheeling diodes are connected directly to each other with additional bonding wires. This connection reduces the effects of parasitic inductances, which can lead to unbalanced voltage loading between the three freewheeling diodes.

Unlike the lowside block, the highside block you can see here has additional bond wires above the freewheeling diodes. One can just speculate that the current distribution was optimized with this wires.


(https://www.richis-lab.de/images/transistoren/a54x05.jpg)

There is an additional copper island just to have a support point for the DC+ bonding wire.


(https://www.richis-lab.de/images/transistoren/a54x21.jpg)

(https://www.richis-lab.de/images/transistoren/a54x22.jpg)

The gate potentials of the IGBTs are contacted in the middle of the die and brought together via a copper strip.

If the module did not provide auxiliary emitters the reverse current of the gate drive would have to flow through the load path (above). This has several disadvantages. Contacting the load path is usually more complex from a interconnect perspective. In addition, the load current and the associated voltage drop affect the gate-emitter voltage. In addition, the detour via the load path increases the impedance in the gate drive.

Using the auxiliary emitter (below) significantly reduces gate circuit expansion. The press-fit pin of the auxiliary emitter reaches the gate drive directly next to the gate potential pin.

It is worth mentioning in this context that the auxiliary emitter pin is not directly connected to the emitter potential in front of it. Instead, the potential is routed a considerable distance to the left. This ensures similarly long leads for all three IGBTs connected in parallel. Such details are usually necessary so that the transistors switch sufficiently synchronously.


(https://www.richis-lab.de/images/transistoren/a54x23.jpg)

In the highside module, the gate circuit is slightly larger.


(https://www.richis-lab.de/images/transistoren/a54x06.jpg)

The bondwires are 400µm in diameter.


(https://www.richis-lab.de/images/transistoren/a54x25.jpg)

Infineon shows the design of the IGBT4 generation used here in the Application Note AN2018-14. These so-called trench field stop IGBTs have a gate electrode that not only rests on the surface but also runs in a trench, where it controls the MOSFET part of the IGBT more efficiently.

In addition, compared to the first generations, the collector was constructed differently so that the transistor could be made thinner. That reduced the saturation voltage. In the newer IGBT7 generation the structures have been further optimized.


(https://www.richis-lab.de/images/transistoren/a54x32.jpg)

A detailed picture of the setup can be found in the Infineon presentation "分立IGBT技术与特性总览“英飞凌杯”第二届嵌入式处理器和功率电子设计应用大奖赛".  ;D


(https://www.richis-lab.de/images/transistoren/a54x24.jpg)

Each IGBT die is 10.3mm x 9.4mm. The transistor is divided into four areas, all of which are contacted three times. In the middle is the gate contact.


(https://www.richis-lab.de/images/transistoren/a54x27.jpg)

(https://www.richis-lab.de/images/transistoren/a54x28.jpg)

The outer area of the die is protected by a thin potting material, probably a polyimide. The emitter contacts are clearly visible in the metal surface. The frame structure is used for E-field control. Dopants are introduced there in such a way that the electric field is as homogeneous as possible. Otherwise, local high field strengths could damage the structures and lead to failure in the long term.


(https://www.richis-lab.de/images/transistoren/a54x26.jpg)

The gate contact of the IGBT is located in the middle of the die. Although a gate resistor of 2.5Ω is specified in the datasheet, no resistor has been visible so far. With this in mind, it seems quite likely that the three stripes to the left of the bondpad represent this resistor. A certain minimum resistance is necessary to prevent oscillation tendencies. When high currents are switched very fast, high-frequency oscillations can occur and the feedback capacitance can switch the transistor on going into a deadly on/off state.

The cross-shaped structure conducts the gate potential throughout the die. To the right of the bondpad is an integrated test pad that appears to have been contacted in two places.

In the cross-shaped distribution network you can see a lot of vias. Through this vias the gate potential is transferred to the deeper polysilicon layer, which then ultimately feeds it to the individual IGBT cells.


(https://www.richis-lab.de/images/transistoren/a54x30.jpg)

(https://www.richis-lab.de/images/transistoren/a54x29.jpg)

The gate potential distribution does not go all the way to the edge. Just before the frame structure, the four emitter areas are connected.


(https://www.richis-lab.de/images/transistoren/a54x31.jpg)

The die is very thin so that it presents as little resistance as possible and heat can be removed as good as possible.


(https://www.richis-lab.de/images/transistoren/a54x33.jpg)

The edge length of the diode is 7,3mm.


(https://www.richis-lab.de/images/transistoren/a54x34.jpg)

The edges of the die are protected with a polyimide layer and the concentric frame structures can be seen.


(https://www.richis-lab.de/images/transistoren/a54x35.jpg)

According to the data sheet, the diodes are so-called "Emitter Controlled Diodes". One must not confuse these diodes with the switched diodes, which are described for example in the IEEE article "Power Diodes with Active Control of Emitter Efficiency". In this article you can find the above picture. There is a normal diode and a bipolar transistor connected in parallel. The bipolar transistor is controlled by a MOSFET structure. These diodes are called "Emitter Controlled Diode" too.

The term "Emitter Controlled Diode" is used at the same time for diodes which just have a somewhat optimized distribution of doping and thus switch less snappy.


https://www.richis-lab.de/BipolarA04.htm (https://www.richis-lab.de/BipolarA04.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 11, 2022, 11:45:32 pm
Very cool!

It occurs to me, the housing is not only easy to remove and not exactly tightly sealed, but also during testing, you might have one of these open and accessible to IR camera or thermocouple probing -- so the dies may be exposed to light, and a black-filled passivation/potting on the dies is probably a good idea.

You can also special-order them without the gorilla-snot filling, to facilitate such probing.

Tim
Title: Re: Transistors - die pictures
Post by: mawyatt on May 12, 2022, 01:50:53 pm
Thats some serious power handling capability and it shows with the multiple bond wires and package/substrate.

In your statement:

"There is an additional copper island just to have a support point for the DC+ bonding wire."

There's an associated image just above that shows a bond wire looping from one pad to another. The bond wire appears to neck down and possibly open. Is this actually open or just an image artifact?

Nice images as usual :-+

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on May 12, 2022, 08:21:03 pm
Thanks!  8)

The strange area of this bondwire is just an image artifact due to the silicone potting.
Actually that is a "normal" picture, no image stacking done, just f/16.  :-/O
Title: Re: Transistors - die pictures
Post by: doktor pyta on May 17, 2022, 05:38:58 pm
https://www.youtube.com/watch?v=AGXzE6qgipw (https://www.youtube.com/watch?v=AGXzE6qgipw)
Title: Re: Transistors - die pictures
Post by: RoGeorge on May 17, 2022, 05:58:54 pm
Wow!  8)
Didn't know 20W can do that!

The next video in that YT channel, "DIY-Optics dot com", is laser etching copper clad for a PCB coil.  :o
Title: Re: Transistors - die pictures
Post by: Noopy on May 17, 2022, 06:04:43 pm
https://www.youtube.com/watch?v=AGXzE6qgipw (https://www.youtube.com/watch?v=AGXzE6qgipw)

Nice! ...but there is still a little "dirt" left...  ;)
Title: Re: Transistors - die pictures
Post by: Noopy on May 17, 2022, 06:39:40 pm
(https://www.richis-lab.de/images/transistoren/a55x02.jpg)

For this one you would need a laser with a little more power.  ;D

RCA called the 2N6254 "premium type from 2N3055 family". It´s a hometaxial transistor (some more information here: https://www.richis-lab.de/2N3055_08.htm (https://www.richis-lab.de/2N3055_08.htm)).

Vceo can go up to 85V compared to 70V in case of the 2N3055. The maximum collector current is specified with 7A continously and 15A peak. Pmax is 150W, where the 2N3055 just can handle up to 115W.


(https://www.richis-lab.de/images/transistoren/a55x01.jpg)

Typical for a hometaxial transistor is the robustness against second breakdown. The SOA of the 2N6254 is actually just limited by the maximum current, the maximum voltage and the maximum power dissipation.


(https://www.richis-lab.de/images/transistoren/11x10.jpg)

In case of RCA's 2N3055, which is also hometaxial, the SOA range is additionally limited by the second breakdown, even if it is just a very small area that has to be avoided.


(https://www.richis-lab.de/images/transistoren/a55x03.jpg)

(https://www.richis-lab.de/images/transistoren/a55x04.jpg)

The design of the transistor strongly reminds one of the RCA 2N3055H, which was also manufactured in 1979 (https://www.richis-lab.de/2N3055_05.htm (https://www.richis-lab.de/2N3055_05.htm)). It is quite likely that both transistors were based on the same design and then binned according to their specifications.


(https://www.richis-lab.de/images/transistoren/a55x05.jpg)

The die shows the familiar structure of a hometaxial transistor. The current is distributed via a solder layer on top of which the contact plates are directly soldered.


(https://www.richis-lab.de/images/transistoren/a55x06.jpg)

In the lower left corner the solder layer is discolored. Most likely very high temperatures occurred here due to damage.


(https://www.richis-lab.de/images/transistoren/a55x07.jpg)

Yeah, the junction is dead in the lower left corner.


(https://www.richis-lab.de/images/transistoren/a55x08.jpg)

(https://www.richis-lab.de/images/transistoren/a55x09.jpg)

A typical hometaxial structure.


https://www.richis-lab.de/BipolarA05.htm (https://www.richis-lab.de/BipolarA05.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 17, 2022, 07:51:08 pm
Love the crystal growth pattern on that solder.  Pure tin I suppose?  Oh, or would they use lead because high temp handling?

Also, if it were tin... whisker growth?  But it looks pretty clean... :D

Tim
Title: Re: Transistors - die pictures
Post by: floobydust on May 17, 2022, 11:52:54 pm
The pattern looks soft though, maybe from an abrasive wash and the maze reminds me of bismuth crystallization a bit.
SOA 2A@80V gee this part was tough, hard to find something like that nowadays.
Title: Re: Transistors - die pictures
Post by: Noopy on May 18, 2022, 03:36:51 am
Well I don´t know what is causing the nice pattern.  :-//


I have update the transistor sorting:

Now we can go on...  8)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on May 18, 2022, 12:14:49 pm
Also, the pattern seems to be aligned over quite a range of distance, maybe even the entire layer; but not to the substrate, the emitter and base blobs are aligned differently.  Possibly seeded by the contact point, whatever orientation started there?  Whatever they did, it probably cooled fairly slowly!

The texture isn't usually very aggressive, for example I've melted bars of fairly pure aluminum (electrical cable) and it grows a soft pattern of dendritic crystals on the free surface.  The first crystals to form, extend up to the molten surface; as it cools, the surrounding liquid shrinks, exposing the first crystals (while they grow a bit more), and other random crystallites intergrow around them.  It's a neat pattern, but not very deep.  (You get distinctive bismuth crystals by seeding growth, then removing it from solution before randomly seeded intergrowth starts.)

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on May 22, 2022, 07:40:38 pm
(https://www.richis-lab.de/images/transistoren/a56x01.jpg)

(https://www.richis-lab.de/images/transistoren/a56x02.jpg)

(https://www.richis-lab.de/images/transistoren/a56x03.jpg)

The GD180 is a germanium transistor with a voltage rating of 60V. It can conduct up to 3A. The letter at the end of the name stands for the hfe of the transistor (A: 18-35, B: 28-56, C: 45-90). The maximum junction temperature is just 75°C. The maximum power dissipation is 5,3W. The cutoff frequency is at least 250kHz.


(https://www.richis-lab.de/images/transistoren/a56x04.jpg)

There is an imprinting in the base plate. Inside it forms a base on which the transistor is placed.


(https://www.richis-lab.de/images/transistoren/a56x05.jpg)

A large white plate was inserted into the housing to bind any moisture that may occur.


(https://www.richis-lab.de/images/transistoren/a56x06.jpg)

(https://www.richis-lab.de/images/transistoren/a56x07.jpg)

Two sheets of metal connect the pins of the package with the transistor. At the pins the metal sheets are bent at an angle of 90°. The design reminds me of the Tesla OC26 (https://www.richis-lab.de/Bipolar94.htm (https://www.richis-lab.de/Bipolar94.htm)). Matching the occurring currents, the sheet metal element at the emitter is significantly thicker than the one at the base.

The base plate is made of copper which ensures an optimal heat dissipation.


(https://www.richis-lab.de/images/transistoren/a56x08.jpg)

Basically it is the normal structure of a germanium transistor. The surfaces are covered with a thin clear protective coating.

Metal chips can be seen at the front edge of the emitter sheet, which most likely occurred while the case was opened.


(https://www.richis-lab.de/images/transistoren/a56x09.jpg)

There are two different solders on the emitter side of the germanium disk. The lower solder is rather yellowish. Usually this solder contains indium and thus serves as a p-dopant. For the contacting of the emitter sheet another rather silver solder was used.

On the germanium disk under the yellowish solder something can be seen that looks like a thin coating.


(https://www.richis-lab.de/images/transistoren/a56x10.jpg)

Does anybody know what that is?  :-//


https://www.richis-lab.de/BipolarA06.htm (https://www.richis-lab.de/BipolarA06.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 08, 2022, 08:45:01 pm
(https://www.richis-lab.de/images/transistoren/a57x01.jpg)

(https://www.richis-lab.de/images/transistoren/a57x02.jpg)

This transistor is used for the development of hybrid circuits, such as the DAC 32 is one (https://www.richis-lab.de/DAC03.htm (https://www.richis-lab.de/DAC03.htm)). The logo identifies the transistor as a component of the Russian manufacturer Pulsar. No further information can be found. I assume the type designation consists just of the characters A479A. 67 could refer to the year 1967.  :-// The component tester says it is a silicon NPN transistor.


(https://www.richis-lab.de/images/transistoren/a57x03.jpg)

(https://www.richis-lab.de/images/transistoren/a57x04.jpg)

If you remove the outer packaging, the transistor with its bondwires is still protected by two plastic discs.


(https://www.richis-lab.de/images/transistoren/a57x05.jpg)

The development model of the double transistor K1NT291B is equipped with a tube socket so that it can be measured before installation (https://www.richis-lab.de/Bipolar71.htm (https://www.richis-lab.de/Bipolar71.htm)).

Here, the bondwires are connected with thicker connecting wires, which in turn are anchored in one of the plastic disks.

For integration into a hybrid circuit, the thin bondwires are cut, the transistor is inserted into the circuit to be built up and the bondwires are connected to the circuit.


(https://www.richis-lab.de/images/transistoren/a57x06.jpg)

The transistor itself has an edge length of round about 1mm and it is protected from environmental conditions by a red potting on both sides.


(https://www.richis-lab.de/images/transistoren/a57x07.jpg)

(https://www.richis-lab.de/images/transistoren/a57x08.jpg)

(https://www.richis-lab.de/images/transistoren/a57x09.jpg)

After removing the potting there remain some residues. Perhaps irregularities in the surface contribute to this irregularities. You need some hydrofluoric acid to remove most of the contamination. Unfortunately the acid removes the colourful  light resonances too. There are still some irregularities on the surface.


(https://www.richis-lab.de/images/transistoren/a57x10.jpg)

The component tester shows where to find collector, base and emitter.

The large contact on the left of the die is not the collector, as you would expect, but the base terminal.

The center square appears to be a via that allows to contact a deeper collector layer. Above this is the base layer.

The right square has to contain the emitter area, which is embedded in the base layer.


https://www.richis-lab.de/BipolarA07.htm (https://www.richis-lab.de/BipolarA07.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on June 09, 2022, 05:11:21 am
 :o
Wow!  Never seen something alike.  At first I thought it's a resonator, or a SAW (Surface Acoustic Wave) filter.
Title: Re: Transistors - die pictures
Post by: MegaVolt on June 09, 2022, 09:54:31 am
No further information can be found. I assume the type designation consists just of the characters A479A. 67 could refer to the year 1967.  :-// The component tester says it is a silicon NPN transistor.
The marking of the transistor is non-standard, which means an experimental sample. The first letter "А" (Cyrillic) denotes the plant - Pulsar. "А479А" (Cyrillic) is most likely a prototype of the transitor 2Т319А (Cyrillic).

Here is information about it: http://www.155la3.ru/2tp319.htm (http://www.155la3.ru/2tp319.htm)
Title: Re: Transistors - die pictures
Post by: MegaVolt on June 09, 2022, 09:56:30 am
Here is an example of a hybrid assembly with similar transistors http://www.155la3.ru/111_k11gi04_31v.htm (http://www.155la3.ru/111_k11gi04_31v.htm)
Title: Re: Transistors - die pictures
Post by: Noopy on June 09, 2022, 12:04:12 pm
No further information can be found. I assume the type designation consists just of the characters A479A. 67 could refer to the year 1967.  :-// The component tester says it is a silicon NPN transistor.
The marking of the transistor is non-standard, which means an experimental sample. The first letter "А" (Cyrillic) denotes the plant - Pulsar. "А479А" (Cyrillic) is most likely a prototype of the transitor 2Т319А (Cyrillic).

Here is information about it: http://www.155la3.ru/2tp319.htm (http://www.155la3.ru/2tp319.htm)

Thanks for you input!  :-+
How do you get from A479A to 2T319A?
Title: Re: Transistors - die pictures
Post by: MegaVolt on June 09, 2022, 12:45:03 pm
How do you get from A479A to 2T319A?
Google gives out some information from a closed forum. Plus the production years are similar.
Title: Re: Transistors - die pictures
Post by: mawyatt on June 09, 2022, 01:37:50 pm
Interesting, didn't know anyone else had used these type of transistors. Recall GE back in 60s had a similar line of transistor die with wire bonds leads and the bonded die dipped in epoxy. These were also used in small hybrids.

Thanks for showing.

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on June 30, 2022, 03:20:08 am
(https://www.richis-lab.de/images/transistoren/a58x01.jpg)

Today just another small 2N2222A.
SGS - The transistor was built into a modul manufactured in 1984 so it has to be SGS ATES.


(https://www.richis-lab.de/images/transistoren/a58x02.jpg)

(https://www.richis-lab.de/images/transistoren/a58x03.jpg)

(https://www.richis-lab.de/images/transistoren/a58x04.jpg)

(https://www.richis-lab.de/images/transistoren/a58x05.jpg)

The edge length is 0,42mm.


https://www.richis-lab.de/BipolarA08.htm (https://www.richis-lab.de/BipolarA08.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 07:10:17 am
(https://www.richis-lab.de/images/transistoren/a59x01.jpg)

I ordered a IRF3708 at Reichelt and in my view that is a counterfeit part. The IRF3708 is a common power MOSFET which is now obsolete and because of that it´s hard to get genuine parts.

The IRF3708 offers a blocking voltage of 30V and conducts up to 62A permanently with a Rdson of 12mΩ. A peak current of 248A is possible. 4,5V Vgs is already sufficient to turn the MOSFET on almost completely.


(https://www.richis-lab.de/images/transistoren/a59x04.jpg)

The datasheet contains a drawing that shows how the marking of the IRF3708 should look like.


(https://www.richis-lab.de/images/transistoren/a59x02.jpg)

(https://www.richis-lab.de/images/transistoren/a59x03.jpg)

The marking of the present IRF3708 shows two clear deviations compared to the drawing in the datasheet. The characters in the bottom line are not shown in pairs on the left and right side but together in the center. However, the International Rectifier logo is particularly striking. Superficially it is well done but a closer look reveals a cylindrical bulge at the top of the circle that the original logo does not have.

The cuts in the cooling fin are less pronounced than shown in the drawing in the datasheet. However, they are not specified there either.


(https://www.richis-lab.de/images/transistoren/a59x05.jpg)

There are no grinding marks on the surface.

In detail the laser inscription looks unclean. The mold material seems to be burned in some places.


(https://www.richis-lab.de/images/transistoren/a59x06.jpg)

(https://www.richis-lab.de/images/transistoren/a59x08.jpg)

(https://www.richis-lab.de/images/transistoren/a59x07.jpg)

The case contains a die with dimensions of 3,6mm x 2,0mm. Two bondwires contact the upper metal layer. The imprints of test pins can still be seen. The gate potential is distributed over the die with one wire each at the upper and lower edge.


(https://www.richis-lab.de/images/transistoren/a59x09.jpg)

On the bottom edge of the die there are the remnants of some letters. "I.R.CORP." reveals that it is indeed a International Rectifier MOSFET. The same abbreviation is found in the IGBT IRG4PH40K (https://www.richis-lab.de/Bipolar35.htm (https://www.richis-lab.de/Bipolar35.htm)). It remains questionable whether it is an IRF3708. The design obviously dates back to the year 2000.


(https://www.richis-lab.de/images/transistoren/a59x10.jpg)

As with the IRG4PH40K mask designations are shown on the upper edge, but these do not allow any conclusion to be drawn about the transistor type.


(https://www.richis-lab.de/images/transistoren/a59x11.jpg)

The upper metal layer is relatively thick. Vertical structures are visible on the surface of the source area.


(https://www.richis-lab.de/images/transistoren/a59x12.jpg)

If the metal layer is removed with hydrochloric acid, the structure of the individual MOSFETs becomes more prominent. The bright stripes are about 3µm wide and keep a distance of about 1µm. The bright areas contact the source areas. In the dark areas there are the gate structures.


(https://www.richis-lab.de/images/transistoren/a59x13.jpg)

The "International Rectifier HEXFET Databook" shows that a HEXFET like the IRF3708 should have a honeycomb structure. The striped structure that can be seen in the present transistor makes it very likely it´s a counterfeit.


https://www.richis-lab.de/FET23.htm (https://www.richis-lab.de/FET23.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: magic on August 08, 2022, 08:24:57 am
I initially read "Rochester" and was like :wtf: :wtf: :wtf:

The logo is dodgy as hell.
I wonder if the word "hexfet" still means anything in IR datasheets.
Does anyone know IR part numbers that aren't advertised as "hexfet", which this device could really be?

<tinfoil hat on>
Maybe the die wasn't made by IR ;D
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 09:33:39 am
This was my thought too: Is a HEXFET today still a HEXFET?  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 01:20:47 pm
By the way:
A short measurement of the Rdson showed 10mOhm at 4,5V at 4A. Not bad at all...
Title: Re: Transistors - die pictures
Post by: magic on August 08, 2022, 03:03:43 pm
But the logo looks fake. What's the breakdown voltage? Gate capacitance?
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 03:47:06 pm
The logo is very strange!  ;D

Quick&Dirty:

Breakdown voltage: 35V

Rdson (@4A):
Ugs=2,8V => 12mOhm
Ugs=4,5V => 10mOhm

Cgs=2,88nF (@1kHz, D-S open, HP4261A)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 08, 2022, 04:32:15 pm
Sounds like Vgs(th) is on the low side of normal, hence the relatively low Rds(on). Lower Id also contributes (Fig.12 (https://www.infineon.com/dgdl/Infineon-IRF3708-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a4015355df7cf5193c)), although maybe not by much given the scale of that plot, hah.

Etching definitely looks bad, but also doesn't seem to be a refurbished (used) part -- plating looks new, matte tin.  (Or is there a process to reproduce that on used parts?).  3-digit date code doesn't seem like it would reward updating the label, either.  And "IR" on the die confirms it's, at worst, a remarked part, with very similar characteristics as it turns out; or a much more exact die clone than anyone should bother with(!?).

Although I have, presumably authentic, IR parts, 2007 date?, that are bright tin (or maybe solder, PbF type in any case), but IR probably used both depending on product/packaging line.  I just forget if I've seen them use matte tin elsewhere, from those years.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 04:50:11 pm
It was a quick&dirty measurement, so there will be some error in the numbers.

IR markings are strange...
Do you remember these IGBTs: https://www.richis-lab.de/Bipolar35.htm (https://www.richis-lab.de/Bipolar35.htm)
A bad and a really bad marking but the silicon seemed genuine.
Is there a second backend for lower quality stuff? Or is someone collecting "still good" scrapped parts and provides them with a self made marking? Perhaps tolerated by IR? No...  ???
Title: Re: Transistors - die pictures
Post by: Noopy on August 08, 2022, 09:14:58 pm
Thank you for your offer but since I have way too much parts here I have to decline. In these modern digital MCUs we won't see very much details.
Title: Re: Transistors - die pictures
Post by: Noopy on August 09, 2022, 07:43:56 pm
(https://www.richis-lab.de/images/transistoren/a60x01.jpg)

One Two more strange IRF3708.

Of the two IRF3708 becomes conductive at a Ugs of 3V. The datasheet of the IRF3708 specifies a maximum of 2,0V. The other MOSFET shows a much too high leakage current of 2mA at Ugs=0V. (Measured by someone else.)

The two transistors are marked the same way. Depending on the light the letters are sometimes very hard to see. If you look at the characters more closely, you can see slight differences in the shapes. One package also appears somewhat darker than the other.


(https://www.richis-lab.de/images/transistoren/a60x02.jpg)

(https://www.richis-lab.de/images/transistoren/a60x03.jpg)

Viewed in the right light ridges stand out that were almost certainly created while the surface was sanded.


(https://www.richis-lab.de/images/transistoren/a60x04.jpg)

(https://www.richis-lab.de/images/transistoren/a60x05.jpg)

Some areas are burned a little too much.


(https://www.richis-lab.de/images/transistoren/a60x14.jpg)

On the left edge the color seem a little inhomogeneous probably due to bad painting after sanding.


(https://www.richis-lab.de/images/transistoren/a60x06.jpg)

And at the underside of the package we can see the paint residues.


(https://www.richis-lab.de/images/transistoren/a60x07.jpg)

Both transistors contain the same type of die.


(https://www.richis-lab.de/images/transistoren/a60x09.jpg)

(https://www.richis-lab.de/images/transistoren/a60x08.jpg)

The die is 3,9mm x 2,5mm. The source area is contacted with two bonding wires.


(https://www.richis-lab.de/images/transistoren/a60x10.jpg)

The transistor is divided in two parts. The gate potential is distributed via a metal frame which encloses the two source areas.


(https://www.richis-lab.de/images/transistoren/a60x11.jpg)

(https://www.richis-lab.de/images/transistoren/a60x12.jpg)

On the left edge there are the remaining of test structures, but they do not give a direct indication what was the manufacturer or the transistor type.


(https://www.richis-lab.de/images/transistoren/a60x13.jpg)

If you look very closely, you can see very thin horizontal structures in the source area.


https://www.richis-lab.de/FET24.htm (https://www.richis-lab.de/FET24.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 11, 2022, 07:03:41 pm
(https://www.richis-lab.de/images/transistoren/a61x01.jpg)

And another strange IRF3708. First Drain current occurs at a Gate-Source-Voltage of 3,0V. That´s not normal.


(https://www.richis-lab.de/images/transistoren/a61x02.jpg)

(https://www.richis-lab.de/images/transistoren/a61x03.jpg)

The marking does not correspond to the pattern shown in the datasheet. In addition, the letters are rather unclean.


(https://www.richis-lab.de/images/transistoren/a61x04.jpg)

(https://www.richis-lab.de/images/transistoren/a61x05.jpg)

(https://www.richis-lab.de/images/transistoren/a61x06.jpg)

(https://www.richis-lab.de/images/transistoren/a61x07.jpg)

The die took some damage. The dimensions are 3,3mm x 2,4mm.

Source is contacted with two bondwires. Relatively long sections rest on the metal layer.


(https://www.richis-lab.de/images/transistoren/a61x08.jpg)

The gate potential is distributed via wires on the upper and lower edges of the die.

Through the metal layer no special structure is visible.


https://www.richis-lab.de/FET25.htm (https://www.richis-lab.de/FET25.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 21, 2022, 05:09:05 pm
(https://www.richis-lab.de/images/transistoren/a62x01.jpg)

That´s an old one!
The Texas Instruments 2N389 is said to be the first freely available silicon power transistor. In the Electronic Design magazine from 1957 (Volume 5 Issue 12) the 2N389 is advertised as new. The present component dates from 1966.

The 2N389 isolates up to 60V (Rbe=33Ω). The collector provides a current carrying capacity of at least 1,5A. Some documents state 2A or even 3A. The datasheet specifies a current gain of 12 to 60 and still guarantees at least a factor of 8 at -55°C. The operating temperature range is very wide at -65°C to 200°C (junction temperature). At 25°C case temperature the 2N389 can dissipate 85W. The cutoff frequency is in the range of 8MHz.


(https://www.richis-lab.de/images/transistoren/a62x04.jpg)

(https://www.richis-lab.de/images/transistoren/a62x02.jpg)

(https://www.richis-lab.de/images/transistoren/a62x03.jpg)

"GN", "2", "3", whatever that means...  :-//
The pins form hooks.


(https://www.richis-lab.de/images/transistoren/a62x05.jpg)

The construction inside the case seems quite modern for its age.


(https://www.richis-lab.de/images/transistoren/a62x06.jpg)

(https://www.richis-lab.de/images/transistoren/a62x07.jpg)

The die is placed on a socket and is contacted with thick bondwires.


(https://www.richis-lab.de/images/transistoren/a62x16.jpg)

The bondwires are not directly welded to the connection pins. There is a metal plate between them.

At this point you can clearly see that the transistor is covered with a thin protective lacquer. Below the bondwire there are larger accumulations of this varnish.


(https://www.richis-lab.de/images/transistoren/a62x08.jpg)

(https://www.richis-lab.de/images/transistoren/a62x10.jpg)

The edge length of the die is 6,4mm. Base and emitter areas interlock. The emitter contact is slightly wider than the base contact. There are minor scratches and dirt on the metallization.


(https://www.richis-lab.de/images/transistoren/a62x09.jpg)

The bond tool has left an unusual imprint on the bondwire.


(https://www.richis-lab.de/images/transistoren/a62x11.jpg)

(https://www.richis-lab.de/images/transistoren/a62x12.jpg)

The 2N389 is a MESA transistor where the silicon is etched down at the edge to create a clean base-collector junction edge. This increases the voltage rating.

The protective varnish has not wetted the entire die. At the edges the silicon surface is exposed.


(https://www.richis-lab.de/images/transistoren/a62x13.jpg)

The junction between base and emitter is clearly visible. Edges stand out at the edges of the metallization. It could be that these are breakthroughs through a protective oxide layer. Perhaps these areas made the protective coating necessary. It would cover gaps between the metal layer and the silicon oxide layer.


(https://www.richis-lab.de/images/transistoren/a62x14.jpg)

(https://www.richis-lab.de/images/transistoren/a62x15.jpg)

The base-emitter junction breaks down at -14V. The datasheet guarantees a dielectric strength of at least -10V. This is a high value for an epitaxial transistor, which indicates a relatively low doping typical for its age. The weak doping certainly is one reason why the 2N389 could be specified for relatively high junction temperatures.

In the upper image the current is 0,1A. The current distribution appears uniform. There are no particular glitches to be seen. In the lower image the current is 1A.


https://www.richis-lab.de/BipolarA09.htm (https://www.richis-lab.de/BipolarA09.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 22, 2022, 01:24:22 am
Wow, mastered it in 1955!  Well, at what yields, is the real question... :D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on August 24, 2022, 04:13:26 pm
Interesting!

I don't know what is going on there. Perhaps the additional sheet makes it easier to weld the two parts?
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on August 24, 2022, 04:35:46 pm
Yeah could be something like that, a diffusion barrier, or a bonding aid (filler?), or both.

Aluminum in particular cannot be bonded to gold (due to formation of an especially brittle intermetallic), but a more compatible or more resistant metal could be used.  I'm not sure what, offhand; not nickel either, as that has the same problem; tin is well-behaved with both, but that's just a soldered joint and may not be strong enough; iron may be okay (intermetallic is still formed, but a harder one, in a thinner interface layer I think, and importantly, it won't tend to degrade over time as for more mobile ions (lower melting substances)); or perhaps harder/refractory metals are used -- I don't know about say chromium or molybdenum, but maybe aluminum just acts like solder on them, not reacting enough to matter?

If you ever get the opportunity to drop it in front of an XRD analyzer, that should tell something. ;D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on August 24, 2022, 04:52:48 pm
If you ever get the opportunity to drop it in front of an XRD analyzer, that should tell something. ;D

I will keep my eyes open...  ;D
Title: Re: Transistors - die pictures
Post by: David Hess on August 25, 2022, 12:35:01 pm
Aluminum in particular cannot be bonded to gold (due to formation of an especially brittle intermetallic), but a more compatible or more resistant metal could be used.  I'm not sure what, offhand; not nickel either, as that has the same problem; tin is well-behaved with both, but that's just a soldered joint and may not be strong enough; iron may be okay (intermetallic is still formed, but a harder one, in a thinner interface layer I think, and importantly, it won't tend to degrade over time as for more mobile ions (lower melting substances)); or perhaps harder/refractory metals are used -- I don't know about say chromium or molybdenum, but maybe aluminum just acts like solder on them, not reacting enough to matter?

Tin has problems with gold also.  Tin solders will form Purple of Cassius at the interface and eventually separate from the gold.  One way to avoid this is to dissolve thick layer of gold into the solder, remove the solder, and then solder the joint again.  Flash gold is suppose to be thin enough to completely dissolve.

https://en.wikipedia.org/wiki/Purple_of_Cassius

I have repaired a few Tektronix instruments from the late 1960s and early 1970s where this happened.
Title: Re: Transistors - die pictures
Post by: Noopy on August 31, 2022, 04:32:45 am
Sounds interesting! :-+ I should take a look into these.
You will have to be patient but sooner or later every part gets its place on my website.  :)
Title: Re: Transistors - die pictures
Post by: mawyatt on August 31, 2022, 01:29:59 pm
Noopy, I have some very old chips from ECI (E-systems) in the USA. They are ceramic carriers with gold (plated?) terminals. The chip seems to be coated in some PMMA and/or glass encapsulation. Would you be interested in photographing some of them?

ECI was in St Pete, Florida, not far from where we are in North Clearwater, Florida. Later they were acquired by E-Systems and now they are Raytheon.

Back in 60s and early 70s they did some Ham Radio Transceivers that were pretty good, and also had an in-house hybrids capability, but don't recall they did actual chip design tho.

Best,
Title: Re: Transistors - die pictures
Post by: Noopy on August 31, 2022, 07:29:44 pm
(https://www.richis-lab.de/images/transistoren/a59x01.jpg)

I ordered a IRF3708 at Reichelt and in my view that is a counterfeit part. The IRF3708 is a common power MOSFET which is now obsolete and because of that it´s hard to get genuine parts.

...



I got feedback from Infineon:


(https://www.richis-lab.de/images/transistoren/a59x15.jpg)

It´s a fake...


https://www.richis-lab.de/FET23.htm#Infineon (https://www.richis-lab.de/FET23.htm#Infineon)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 03, 2022, 09:07:40 pm
(https://www.richis-lab.de/images/transistoren/a63x02.jpg)

(https://www.richis-lab.de/images/transistoren/a63x01.jpg)

(https://www.richis-lab.de/images/transistoren/a63x03.jpg)

Some more Germanium. The П605A (P605A) from the Latvian manufacturer ALFA is a germanium power transistor designed for operation up to 30MHz. The datecode refers to a production in January 1967.

The voltage rating is typically 45V. The A-variant is the better grade of the P605. The datasheet states a maximum gain of round about 85 at a collector current of 0,4A. The peak current may rise to 1,5A for a short time. With a heatsink that offers a thermal resistance of less than 5°K/W up to 3W can be dissipated. The maximum permissible junction temperature is 85°C.


(https://www.richis-lab.de/images/transistoren/a63x04.jpg)

The die is protected with a potting that looks like silicone.


(https://www.richis-lab.de/images/transistoren/a63x06.jpg)

Unfortunately even with silicone solvent the potting cannot be completely removed.


(https://www.richis-lab.de/images/transistoren/a63x05.jpg)

The pins are connected to the die via a relatively large number of bondwires. The bondwire of the emitter (left) is led from the pin to the die and from there back to the pin. The base potential is connected twice like in the AU103 (https://www.richis-lab.de/Bipolar03.htm (https://www.richis-lab.de/Bipolar03.htm)) and the GT906 (https://www.richis-lab.de/Bipolar84.htm (https://www.richis-lab.de/Bipolar84.htm)). Here, too, the bondwires lead from the pin to the die and back again.


(https://www.richis-lab.de/images/transistoren/a63x07.jpg)

The complete die measures 4,0mm x 2,5mm. The active area inside is 2,5mm x 1,2mm. Each of the two base bondwires is connected to the die twice. The emitter bondwire contacts the die just once in the middle.

This is a so-called diffusion-alloyed MESA transistor. The site describing the 2N1561 (https://www.richis-lab.de/Bipolar17.htm (https://www.richis-lab.de/Bipolar17.htm)) contains more information about these transistor type. While the emitter region is located only inside the die, the base contact regions extend across the entire width of the die.


(https://www.richis-lab.de/images/transistoren/a63x08.jpg)

(https://www.richis-lab.de/images/transistoren/a63x10.jpg)

(https://www.richis-lab.de/images/transistoren/a63x09.jpg)

The MESA trenches, which are approximately 100µm wide at the surface, ensure that the outer edges of the base-collector junction have as few imperfections as possible. Imperfections would increase the leakage current and reduce the dielectric strength. In a transistor that is to be used for high frequencies the MESA structure has another important function. It reduces the base-collector area and thus the base-collector capacitance.

While in the 2N1561 the MESA structure was obviously etched into the die, here it appears it had been cut. This is indicated by the fact that the transverse and longitudinal trenches are of different depths. At the same time, however, all surfaces show the typical structures that result from an etching process. It could be that the ditches were cut first and then the entire die went through another etching process to clean the surface and remove imperfections.


https://www.richis-lab.de/BipolarA10.htm (https://www.richis-lab.de/BipolarA10.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Weston on October 20, 2022, 06:06:09 pm
My photos are not as good as Noopy's, but I took some cool photos recently that I think are worth sharing.

The die of a 2N3439 transistor in visible light, as well as photos showing the light emissions under Emitter-Base breakdown, and the IR light emitted when the base junction is forward biased. On a CMOS sensor with the IR filter removed there is just enough IR sensitivity to see the IR light emitted by PN junctions in forward bias. 

I think it's interesting to see the three different photos side by side. I am working on touching up and adjusting them so I can get prints made.

[attachimg=1]
[attachimg=2]
[attachimg=3]
Title: Re: Transistors - die pictures
Post by: magic on October 20, 2022, 06:18:06 pm
On a CMOS sensor with the IR filter removed there is just enough IR sensitivity to see the IR light emitted by PN junctions in forward bias.
Interesting possibility.

Webcams could work for this because their IR sensors are simply glued to the internal end of the lens, very easy to remove.
I can definitely confirm that removing it makes some kind of difference, rendering the lens hardly usable in normal imaging :P

BTW, how much forward current and how much exposure time does it take to see that IR?
Title: Re: Transistors - die pictures
Post by: Noopy on October 20, 2022, 07:42:35 pm
Nice! :-+
Title: Re: Transistors - die pictures
Post by: Noopy on October 26, 2022, 07:24:20 pm
(https://www.richis-lab.de/images/transistoren/a64x01.jpg)

(https://www.richis-lab.de/images/transistoren/a64x02.jpg)

(https://www.richis-lab.de/images/transistoren/a64x03.jpg)

We had the ALFA P605A (https://www.richis-lab.de/BipolarA10.htm (https://www.richis-lab.de/BipolarA10.htm)), now let´s take a look into a newer ALFA П609A (P609A) which is built 1986. It is, like the P605A, a germanium-based, diffusion-alloyed MESA transistor.

The cutoff frequency of the P609A is in the range of 100MHz. The maximum collector-base-voltage is given with 35V. The amplification factor is typically 150. The P609A can carry a collector current of 0,3A, pulses up to 0,6A are allowed. The datasheet presents the power dissipation as a function of the applied collector-emitter voltage. At 20V 1,5W can be dissipated. At 30V just 0,5W can lead to problematic leakage currents. Above an ambient temperature of 40°C the power limits decrease further.


(https://www.richis-lab.de/images/transistoren/a64x04.jpg)

As with the P605A, the die is protected with a silicone-like potting.


(https://www.richis-lab.de/images/transistoren/a64x05.jpg)

The potting can be dissolved with silicone remover. The remains can be rinsed out with isopropanol.

The connections between the pins and the die are the same as in the P605A. The base potential (right) is supplied via four bond wires. The emitter connection has two bonding wires.


(https://www.richis-lab.de/images/transistoren/a64x07.jpg)

(https://www.richis-lab.de/images/transistoren/a64x06.jpg)

The dimensions of the die are 2,1mm x 1,6mm. It is thus significantly smaller than the die of the P605A (4,0mm x 2,5mm). The active area with 1,2mm x 0,7mm is also significantly smaller than the P605A (2,5mm x 1,2mm). This explains the higher cutoff frequency (100MHz vs. 30MHz), since the parasitic capacitances are smaller (base-collector capacitance: 21pF vs. 70pF).


(https://www.richis-lab.de/images/transistoren/a64x08.jpg)

Here, the MESA area was clearly created by an etching process.


(https://www.richis-lab.de/images/transistoren/a64x09.jpg)

(https://www.richis-lab.de/images/transistoren/a64x10.jpg)

The structures of the base and emitter contacts differ because they were built with different alloys. Details can be found on the 2N1561 page (https://www.richis-lab.de/Bipolar17.htm (https://www.richis-lab.de/Bipolar17.htm)).


https://www.richis-lab.de/BipolarA11.htm (https://www.richis-lab.de/BipolarA11.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 31, 2022, 09:04:35 pm
(https://www.richis-lab.de/images/transistoren/a65x01.jpg)

(https://www.richis-lab.de/images/transistoren/a65x02.jpg)

(https://www.richis-lab.de/images/transistoren/a65x03.jpg)

The GD241 is a germanium power transistor with a Vce of 35V (Rbe=50Ω). It can conduct up to 3A. The letter at the end of the designation, here an A, stands for the gain factor of the transistor (A: 18-35, B: 28-56, C: 45-90). The datasheet specifies the maximum junction temperature as 85°C. This is 10°C higher than the GD180 (https://www.richis-lab.de/BipolarA06.htm (https://www.richis-lab.de/BipolarA06.htm)), which is probably one reason why the maximum power dissipation of 10W is twice as high. ft is at least 450kHz. The sign following the letter A is the logo of the "Röhrenwerk Neuhaus".


(https://www.richis-lab.de/images/transistoren/a65x04.jpg)

A large white plate was inserted into the housing to bind any moisture that may occur.


(https://www.richis-lab.de/images/transistoren/a65x05.jpg)

The construction of the transistor corresponds to the construction of the GD180. This is not surprising, since this GD180 was manufactured in the Röhrenwerk Neuhaus too.

In the overview you can already see that dendrites were formed in this transistor. Similar dendrites were found in the Tesla GD609 (https://www.richis-lab.de/Bipolar65.htm (https://www.richis-lab.de/Bipolar65.htm)). In the GD609, however, the inside of the case was heavily corroded, no traces of corrosion can be found here.


(https://www.richis-lab.de/images/transistoren/a65x06.jpg)

The dendrites are mainly located at the front edge of the element that contacts the emitter and around the base ring. Dendrites have also formed on the pin bushing. Smaller parts have broken off and are lying on the bottom of the housing.


(https://www.richis-lab.de/images/transistoren/a65x07.jpg)

(https://www.richis-lab.de/images/transistoren/a65x08.jpg)

The finely branched dendrites are difficult to image photographically. Especially with several dendrites in different focus planes, focus stacking often does not provide an optimal image. Even with a lot of post-processing, some weaknesses remain. In this case, development into two different focus areas makes it somewhat easier to recognize the dendrites.


(https://www.richis-lab.de/images/transistoren/a65x09.jpg)

(https://www.richis-lab.de/images/transistoren/a65x10.jpg)

Most of the dendrites of the emitter junction originate from the upper edge and grow horizontally or slightly upwards. However, dendrites have also formed on the lower edge, approaching the base ring.


(https://www.richis-lab.de/images/transistoren/a65x11.jpg)

(https://www.richis-lab.de/images/transistoren/a65x12.jpg)

(https://www.richis-lab.de/images/transistoren/a65x14.jpg)

The larger dendrites sometimes form quite massive structures. At the ends, however, they always have very fine branching. It remains unclear which metals are in the dendrites.


(https://www.richis-lab.de/images/transistoren/a65x13.jpg)

In some cases, the tips of the uppermost dendrites carry remnants of the desiccant.


(https://www.richis-lab.de/images/transistoren/a65x15.jpg)

The dendrites are not only formed in areas covered with solder. Such crystals are also found between the pin and the emitter contact plate.


(https://www.richis-lab.de/images/transistoren/a65x16.jpg)

(https://www.richis-lab.de/images/transistoren/a65x18.jpg)

Dendrites have also formed on the base ring. One of those that grew in the direction of the emitter contact has an unusually round structure at the tip. It could be that a short circuit had already formed here, which then melted due to the current flow.


(https://www.richis-lab.de/images/transistoren/a65x17.jpg)

(https://www.richis-lab.de/images/transistoren/a65x19.jpg)

Another dendrite is already very close to the emitter contact.


(https://www.richis-lab.de/images/transistoren/a65x20.jpg)

(https://www.richis-lab.de/images/transistoren/a65x21.jpg)

(https://www.richis-lab.de/images/transistoren/a65x22.jpg)

The majority of the dendrites on the base ring are directed toward the base plate of the transistor. Here, however, it may be that the drying tablet has bent the dendrites downward.


https://www.richis-lab.de/BipolarA12.htm (https://www.richis-lab.de/BipolarA12.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 07, 2022, 04:51:34 am
(https://www.richis-lab.de/images/Transistoren/51x01.jpg)

(https://www.richis-lab.de/images/Transistoren/51x04.jpg)

A long time ago I had a TPIC2404.


(https://www.richis-lab.de/images/Transistoren/51x08.jpg)

There are protection structures at the input but they are not easy to read and my first interpretation was probably wrong.

It seems there are two transistors. The one transistor is clearly visible (yellow). The potential of the bondpad is apparently conducted from the upper metal layer to the collector via the lower metal layer. The collector area appears purple. The buried collector shows up as a thin frame. The frame is somewhat displaced, which often occurs with low-lying layers. The collector potential is tapped at the top edge and routed to the rest of the TPIC2404 circuitry. Between the two collector contacts are one emitter and two base terminals. The emitter is connected directly to ground, while the base is connected to ground via a resistor.

The structure below the first transistor seems to represent a more unconventional transistor (cyan). While the upper transistor has a vertical structure, the lower transistor is a lateral transistor. The collector area, which is connected to the ground potential, can be seen directly. With the p-doped isolation frames and the adjacent n-doped collector areas of the first transistor, another NPN transistor is formed. The dopants and the shapes of this transistor are of course rather unusual.


(https://www.richis-lab.de/images/Transistoren/51x10.jpg)

You get the following circuit. Normally, both transistors should block the voltage. The transistor Q2 should serve as protection against negative voltages. It ensures that no uncontrolled current flows through the substrate. If there is a negative potential at the bondpad, the transistor will conduct current directly from the adjacent ground terminal.

Transistor Q1 serves as overvoltage protection. With a suitable design, this transistor breaks down before the rest of the circuit is damaged and diverts overvoltage pulses on a direct path to ground.


https://www.richis-lab.de/Bipolar30.htm (https://www.richis-lab.de/Bipolar30.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 13, 2022, 07:56:38 am
(https://www.richis-lab.de/images/transistoren/a66x01.jpg)

E1 => BFS17, a HF transistor with a ft of round about 2GHz. Vce is 25V and Ic is allowed to go up to 25mA. The low Veb of 2,5V shows how much dopand is in the silicon.


(https://www.richis-lab.de/images/transistoren/a66x02.jpg)

(https://www.richis-lab.de/images/transistoren/a66x03.jpg)

The die of the BFS17 is very small, measuring 0,32mm x 0,28mm.
It is really hard to clean...  ::)


(https://www.richis-lab.de/images/transistoren/a66x04.jpg)

The transistor has the typical structure where base and emitter contacts mesh on the base surface.


https://www.richis-lab.de/BipolarA13.htm (https://www.richis-lab.de/BipolarA13.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 26, 2022, 04:27:20 am
The die of a 2N3439 transistor in visible light, as well as photos showing the light emissions under Emitter-Base breakdown, and the IR light emitted when the base junction is forward biased. On a CMOS sensor with the IR filter removed there is just enough IR sensitivity to see the IR light emitted by PN junctions in forward bias. 

Weston did the first IR pictures in this thread.
I had planned to do some IR pictures too. Now here they are.
For the a first try I took a bulky BUX22 but I will do more complex (and interesting?) parts too.


(https://www.richis-lab.de/images/transistoren/a67x01.jpg)

This BUX22 from 1987 is still labeled with the Thomson Semiconducteurs logo. My BUX22 from 1988, on the other hand, already bears the logo of ST Microelectronics: https://www.richis-lab.de/Bipolar07.htm (https://www.richis-lab.de/Bipolar07.htm)


(https://www.richis-lab.de/images/transistoren/a67x02.jpg)

Like the BUX22 from 1988, the base plate of the case is very thick. It thus represents a quite efficient heatspreader.


(https://www.richis-lab.de/images/transistoren/a67x03.jpg)

The pins are very thick, which makes absolute sense for currents up to 50A.


(https://www.richis-lab.de/images/transistoren/a67x04.jpg)

(https://www.richis-lab.de/images/transistoren/a67x05.jpg)

(https://www.richis-lab.de/images/transistoren/a67x06.jpg)

It turns out that this BUX22 is built the same way like the BUX22 from 1988.


(https://www.richis-lab.de/images/transistoren/a67x08.jpg)

(https://www.richis-lab.de/images/transistoren/a67x07.jpg)

(https://www.richis-lab.de/images/transistoren/a67x09.jpg)

No differences can be seen in the details either.


[end of part 1]

Title: Re: Transistors - die pictures
Post by: Noopy on November 26, 2022, 04:28:35 am
[part 2]


(https://www.richis-lab.de/images/transistoren/a67x10.jpg)

First some BE breakdown (-13V, 0,01A). Unlike the BUX22 from 1988 (https://www.richis-lab.de/Bipolar07.htm (https://www.richis-lab.de/Bipolar07.htm)), the two transistors in this BUX22 behave significantly differently.


(https://www.richis-lab.de/images/transistoren/a67x11.jpg)

Even with a current of 0,1A the left transistor still remains almost completely dark.


(https://www.richis-lab.de/images/transistoren/a67x12.jpg)

At a current of 0,5A a relevant current flow also starts in the left transistor.


(https://www.richis-lab.de/images/transistoren/a67x13.jpg)

Up to a current of 1A the differences are still clearly visible. While with asymmetrical light effects on one die one can assume an inhomogeneous structure, the different light appearance on the two dies does not necessarily tell something about the current distribution in normal operation.


[end of part 2]

Title: Re: Transistors - die pictures
Post by: Noopy on November 26, 2022, 04:29:47 am
[part 3]


(https://www.richis-lab.de/images/transistoren/a67x14.jpg)

If a current flows across a pn junction, charges recombine there. During recombination, partially photons are emitted. Light emitting diodes are based on this effect. In light emitting diodes, so called direct semiconductors are used, in which it is very likely that recombination is associated with the emission of a photon.

In contrast, silicon is an indirect semiconductor. If charges recombine with light radiation, they must emit a phonon as well as a photon. Phonons are lattice vibrations which ultimately increase the temperature of the semiconductor. At the same time, this means that recombination is much less likely and the energy remaining for the emitted photons is reduced by the energy of the phonons. A large fraction of the charges recombine nonradiatively, passing energy to other electrons as part of the Auger effect, which ultimately heats the semiconductor.

The small bandgap of silicon and indirect recombination mean that just relatively long-wavelength radiation is produced in the pn interface. This infrared radiation is not readily visible. Normal SLR cameras have infrared filters in front of the sensor. If this filter is removed, the infrared radiation can be made visible. However, the camera and its optics are not optimized for such long wavelengths, which means that the exposure metering no longer works perfectly and the image quality is not optimal in every case.

Here, a current of 1A flows across the base-emitter path of the BUX22. The Canon EF 100mm f/2.8L Macro lens was used in its normal configuration. With an aperture of 2.8 and ISO 1600, nevertheless an exposure time of 2s is necessary to make the relatively dark purple glow visible. A closer look already shows that the glow is somewhat blurred compared to the rest of the image and radiates beyond the spaces between the metal.


(https://www.richis-lab.de/images/transistoren/a67x15.jpg)

If you set a CE current of 5A and hold the BE current at 1A, the luminous effect will be slightly brighter.


(https://www.richis-lab.de/images/transistoren/a67x16.jpg)

With a CE current of 10A the light intensity is already significantly higher.


(https://www.richis-lab.de/images/transistoren/a67x17.jpg)

With 15A a certain concentration of the luminance into the center of the transistors occurs. Here the over-radiation into the metal layer is clearly visible.


(https://www.richis-lab.de/images/transistoren/a67x18.jpg)

The following images were taken with the Canon EF-S 10-22mm f/3.5-4.5 lens in retro position. This configuration shows significantly less outshining.

At an ISO of 3200 and an exposure time of 3,2s the glow of a BE current of 0,5A is just visible.


(https://www.richis-lab.de/images/transistoren/a67x19.jpg)

If the CE current is increased to 5A, the glow becomes brighter, especially at the long edges of the emitter contacts. At the outer edges and in the center, the interfaces are somewhat darker.


(https://www.richis-lab.de/images/transistoren/a67x20.jpg)

With a current of 10A through the collector the light color seems to shift slightly to reddish. The light intensity increases and the inner areas also become brighter.


(https://www.richis-lab.de/images/transistoren/a67x21.jpg)

If the collector current is increased to 15A, the concentration of the luminance on the inside of the transistor also becomes apparent here.


https://www.richis-lab.de/BipolarA14.htm (https://www.richis-lab.de/BipolarA14.htm)

 :-/O 8)
Title: Re: Transistors - die pictures
Post by: RoGeorge on November 26, 2022, 09:22:32 am
The junction starts to emit visible light in localized dots of light at first, but in infra red the light seems to be uniformly spread, just dimmer at lower currents.  Why no dots seen in IR?
Title: Re: Transistors - die pictures
Post by: Noopy on November 26, 2022, 09:29:51 am
The visible light comes in reverse breakdown. It's an avalanche effect. Like in zener diodes that's a local effect. There is a weakest point breaking down and the next one comes as soon as the current through the first one is high enough to rise the voltage above the breakdown voltage of the next area.

The IR comes in normal conduction mode. The manufacturer do everything to get that current (and light) as uniform as possible. Otherwise you get problems with hot spots. Distributed emitter resistance helps for example.
Title: Re: Transistors - die pictures
Post by: Noopy on December 02, 2022, 07:23:38 pm
Some more IR light!  8)

Do you remember the SF137 built by the Halbleiterwerk Frankfurt Oder:


(https://www.richis-lab.de/images/transistoren/a18x01.jpg)

(https://www.richis-lab.de/images/transistoren/a18x02.jpg)

(https://www.richis-lab.de/images/transistoren/a18x06.jpg)

(https://www.richis-lab.de/images/transistoren/a18x07.jpg)

A small "HF" transistor with a common design.


(https://www.richis-lab.de/images/transistoren/a18x08.jpg)

(https://www.richis-lab.de/images/transistoren/a18x09.jpg)

(https://www.richis-lab.de/images/transistoren/a18x10.jpg)

As described with the Thomson Semiconducteurs BUX22, an infrared image can be used to visualize where charges recombine.

In the above images, Ibe is 30mA while Ice increases from 0A to 0,1A to 0,2A. Without collector current, most of the light occurs in the base region. On closer inspection, one can guess that the emitter region is less bright. As Ice increases, the light shifts toward the emitter, while the base region becomes darker.


(https://www.richis-lab.de/images/transistoren/a18x11.jpg)

The picture above is taken from the IEEE publication "Multi-dimensional current flow in silicon power transistors operating in the saturation mode" by R. A. Sunshine and has been recolored here. The document explains the background of the different light phenomena. It is important to understand that in a normal bipolar transistor there is a parasitic diode next to the transistor itself. It is formed between base and collector.

One might think that a base-emitter current would choose the shortest path from the base to the emitter. However, as long as there is not too much collector current flowing, the dominant current path is completely different. The special structure of a bipolar transistor with its very thin base layer ensures that most of the electrons (cyan) leaving the emitter pass through the base region and arrive in the collector. For the positive charges (purple), the path to the collector is in most cases more attractive than the path to the emitter. Consequently, the base current first flows into the collector and from there to the emitter.

Apart from isolated recombination effects under the emitter, most of the recombination takes place under the base terminal, where the corresponding light effect occurs.


(https://www.richis-lab.de/images/transistoren/a18x13.jpg)

This image is taken from the IEEE publication too (and was recolored). It shows the charge movements with increasing collector current. The more electrons flow from emitter to collector and leave the transistor there, the fewer electrons flow from the collector back to the base terminal. The positive charge carriers of the base flow into the base area under the emitter, where they provide the necessary drive of the transistor. Recombination and the associated luminous effect shift accordingly to the emitter area.


(https://www.richis-lab.de/images/transistoren/a18x12.jpg)

A comparison at different Ibe and Ice is difficult, because the light intensity is very low and the camera system does not work very efficiently in the infrared range. However, certain tendencies can be seen quite well.

As long as no Ice is flowing, the luminance in the base area increases with increasing Ibe. The luminous area seems to increase a little. The emitter area always remains slightly darker. With increasing Ice, the luminous effect is concentrated in the emitter area and the base area becomes darker. At high Ibe the base area never becomes completely dark.

The combination of a small Ibe with a very large Ice stands out, because there the emitter region is much brighter than at the medium base currents. Here the transistor is operated in saturation. This ensures maximum concentration of the recombination region. Not only does the recombination take place completely in the emitter area, it is also limited to the edge of the emitter area, which further increases the luminance there.


https://www.richis-lab.de/Bipolar75.htm#IR (https://www.richis-lab.de/Bipolar75.htm#IR)

 :-/O
Title: Re: Transistors - die pictures
Post by: SilverSolder on December 04, 2022, 01:22:58 pm
Very interesting stuff.  So does this mean that effectively, the 'resistance' in a semiconductor 'happens' at the junction - and that's why it gets hot there?  I.e. there is no way around Ohm's law, even for a semiconductor (there is equivalent "resistance" at the junction, and putting a current through it will make it hot).
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on December 04, 2022, 02:28:13 pm
Sort of.  Resistive loss is non emissive.  Remember this is near IR, not far (thermal).  We're seeing recombination here -- weakly because silicon is indirect bandgap, but still something.

It's also not where heat is generated, because the C-B junction isn't glowing when it's reverse biased (Vce > Vce(sat))!

This is just showing where the diode-like current flows.  And it's fairly remarkable to see the base current flow into the collector to the emitter.

..I mean, in saturation, it is where heat is generated, but still not quite in proportion because the emitter is generally brighter but most of the dissipation is still in the collector.

Hope that clears things up :)

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on December 04, 2022, 02:30:18 pm
Very interesting stuff.  So does this mean that effectively, the 'resistance' in a semiconductor 'happens' at the junction - and that's why it gets hot there?  I.e. there is no way around Ohm's law, even for a semiconductor (there is equivalent "resistance" at the junction, and putting a current through it will make it hot).

Your point is that the IR at the junction generates most of the losses?
I'm pretty sure the IR is just a small part of the power dissipation. Silicon is a very inefficient light source. Most recombinants don't dissipate a photon. I need ISO 32.000 and 4 seconds and more than 10mA before I see any light.
One important point to get low losses is a low collector resistance. That is why today you have a n++ collector contact and a likewise thin n collector.

Edit: And everything Tim said.  ;D
Title: Re: Transistors - die pictures
Post by: SilverSolder on December 04, 2022, 09:15:13 pm

I see, thank you both,  I wasn't appreciating that the IR radiation seen is not actually caused by heat but instead is a side effect of recombination.  That is rather amazing, actually -  seeing electrons at work, almost!

Title: Re: Transistors - die pictures
Post by: Noopy on December 05, 2022, 07:42:51 pm
(https://www.richis-lab.de/images/transistoren/a62x01.jpg)

(https://www.richis-lab.de/images/transistoren/a62x10.jpg)

I once again took the 2N389 with its wide gap between the base and the emitter metallization and took some IR pictures...


(https://www.richis-lab.de/images/transistoren/a62x17.jpg)

Compared with the SF137 here the base current is on the Y-axis and the collector current is on the X-axis. Without collector current, only the base region is illuminated, below which at the base-collector junction much of the recombination occurs. As the current increases, the light intensity increases.

At high base currents the luminous effect and thus most of the recombination shifts from the base area to the emitter area as the collector current increases. Here, the base current no longer flows via the collector to the emitter, but directly to the emitter in the base layer. At a base current of 0,4A and a collector current of 1A, the separation of base and emitter area can be seen nicely.

At low base currents (0,1A) and high collector currents (3A) the light is concentrated at the edges of the emitter surface. That´s were current crowding takes place, and a large part of the collector-emitter current flows through the edges. The transistor no longer operates in saturation here. In contrast to the SF137, the concentration of the luminance does not increase the brightness.


(https://www.richis-lab.de/images/transistoren/a62x18.jpg)

At a higher magnification, the images appear darker in particular. Otherwise, no other special features can be seen.


https://www.richis-lab.de/BipolarA09.htm#IR (https://www.richis-lab.de/BipolarA09.htm#IR)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2022, 08:43:29 pm
(https://www.richis-lab.de/images/transistoren/a68x01.jpg)

Just a small Philips BC548C...
Vce is a little lower than for the BC547C (https://www.richis-lab.de/Bipolar44.htm (https://www.richis-lab.de/Bipolar44.htm)).


(https://www.richis-lab.de/images/transistoren/a68x02.jpg)

(https://www.richis-lab.de/images/transistoren/a68x03.jpg)

The edge length of the die is 0,32mm. It is thus larger than the die of the BC547, although Vce is lower. Perhaps this is an older design.

The comparison with the PNP transistor BC560 is interesting (https://www.richis-lab.de/Bipolar52.htm (https://www.richis-lab.de/Bipolar52.htm)). The BC560 used the same design.


https://www.richis-lab.de/BipolarA15.htm (https://www.richis-lab.de/BipolarA15.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: David Hess on December 08, 2022, 01:58:49 am
Just a small Philips BC548C...
Vce is a little lower than for the BC547C (https://www.richis-lab.de/Bipolar44.htm (https://www.richis-lab.de/Bipolar44.htm)).

I always thought these were the same production but graded for Vce.  My own tests with a curve tracer showed that the lower voltage versions often met the higher voltage breakdown specifications.
Title: Re: Transistors - die pictures
Post by: Noopy on December 08, 2022, 02:35:10 am
Just a small Philips BC548C...
Vce is a little lower than for the BC547C (https://www.richis-lab.de/Bipolar44.htm (https://www.richis-lab.de/Bipolar44.htm)).

I always thought these were the same production but graded for Vce.  My own tests with a curve tracer showed that the lower voltage versions often met the higher voltage breakdown specifications.

Perhaps they are the same production. Since I don't know how old these transistors are it is possible that we look at different generations.
Title: Re: Transistors - die pictures
Post by: Noopy on December 09, 2022, 07:26:49 pm
I now have a BC section to clear the listing a little: https://www.richis-lab.de/Transistoren_BC.htm (https://www.richis-lab.de/Transistoren_BC.htm)


(https://www.richis-lab.de/images/transistoren/a69x01.jpg)

The Philips BC328 is a PNP transistor with a permanent current carrying capacity of 500mA, 1000mA is permissible for a short time. The BC328 blocks up to 25V. The cut-off frequency is 100MHz.


(https://www.richis-lab.de/images/transistoren/a69x02.jpg)

(https://www.richis-lab.de/images/transistoren/a69x03.jpg)

The die with an edge length of 0,57mm corresponds to the design of the MPSA56 (https://www.richis-lab.de/Bipolar38.htm (https://www.richis-lab.de/Bipolar38.htm)). Compared to other transistors of the BCxxx family, it is relatively large. That is necessary to achieve the specified current carrying capacity. For the same reason, there are relatively large interlocking metal contacts on the die, as we known them from power transistors.


https://www.richis-lab.de/BipolarA16.htm (https://www.richis-lab.de/BipolarA16.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 10, 2022, 07:57:04 pm
(https://www.richis-lab.de/images/transistoren/a70x01.jpg)

The BC338 is the complementary variant of the BC328. The NPN transistor blocks up to 25V, conducts up to 0,5A continuously and 1A for a short time. The cutoff frequency is 100MHz. The current gain factor ranges from 100 to 600.


(https://www.richis-lab.de/images/transistoren/a70x02.jpg)

(https://www.richis-lab.de/images/transistoren/a70x03.jpg)

The edge length of the die is 0,47mm. Thus, it is slightly smaller than the die of the BC328. This is plausible as far as NPN transistors are usually a bit more efficient than PNP transistors.


https://www.richis-lab.de/BipolarA17.htm (https://www.richis-lab.de/BipolarA17.htm)[/b

 :-/O
Title: Re: Transistors - die pictures
Post by: Sherlock Holmes on December 10, 2022, 10:32:08 pm
How about a transistor-die-picture-topic?  :)

I have collected some here:

https://www.richis-lab.de/Transistoren.htm (https://www.richis-lab.de/Transistoren.htm)


And I just have to show you this one:

(https://www.richis-lab.de/images/Transistoren/02x09.gif)

You see the breakdown of the KD501-base-emitter-junction with increasing current.  8) ;D


(https://www.richis-lab.de/images/Transistoren/02x07.jpg)

Does anybody know why Tesla integrated this step at the edge of the die?

What truly superb images, absolutely astonishing, keep this up!

Title: Re: Transistors - die pictures
Post by: Noopy on December 11, 2022, 06:23:33 am
Thanks!
I still have a big stockpile of pictures and parts too. :-+ 8) As usual: old and new, expensive and low-cost, bulky transistors and tiny complex wonder parts...
Title: Re: Transistors - die pictures
Post by: Kokoriantz on December 14, 2022, 03:05:38 am
Is there a right way to open TO 220 to see the die? I want to compare both Chinese TDA2050 and LM1875.
Title: Re: Transistors - die pictures
Post by: Noopy on December 14, 2022, 03:51:05 am
Is there a right way to open TO 220 to see the die? I want to compare both Chinese TDA2050 and LM1875.

We have discussed how to decap parts in this topic: https://www.eevblog.com/forum/projects/decapping-and-chip-documentation-howto/ (https://www.eevblog.com/forum/projects/decapping-and-chip-documentation-howto/)
And there you can find how I do it.
Title: Re: Transistors - die pictures
Post by: Noopy on December 18, 2022, 08:09:17 pm
(https://www.richis-lab.de/images/transistoren/a71x01.jpg)

Another small old Philips transistor. The Philips BC558 PNP transistor has the same datasheet as the BC556. The BC558 is significantly less voltage resistant with 30V, but offers higher amplification factors. In the B variant, the BC556 and BC558 do not differ in this respect. However, the C variant with an amplification factor of 420 to 800 only exists with the BC558. The current carrying capacity is specified with 100mA, 200mA is permissible for a short time. The cutoff frequency is at least 100MHz.


(https://www.richis-lab.de/images/transistoren/a71x02.jpg)

(https://www.richis-lab.de/images/transistoren/a71x03.jpg)

The edge length of the die is 0,32mm. The design can also be found in the PNP transistor BC560C (https://www.richis-lab.de/Bipolar52.htm (https://www.richis-lab.de/Bipolar52.htm)). The NPN transistor BC548C (https://www.richis-lab.de/BipolarA15.htm (https://www.richis-lab.de/BipolarA15.htm)) contains these structures too, but the outer metal frame has been omitted.


https://www.richis-lab.de/BipolarA18.htm (https://www.richis-lab.de/BipolarA18.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 20, 2022, 08:01:50 pm
(https://www.richis-lab.de/images/Transistoren/50x03.jpg)
...
(https://www.richis-lab.de/images/Transistoren/50x09.jpg)

I took some IR pictures of the HFO SL113, this old HF silicon transistor:


(https://www.richis-lab.de/images/transistoren/50x13.jpg)

In this image a current flows across the base-emitter junction with the collector open. As described with the SF137 (https://www.richis-lab.de/Bipolar75.htm#IR (https://www.richis-lab.de/Bipolar75.htm#IR)), some light occurs at the base-collector junction. The light is very non-uniform. The upper area remains dark and in the lower area, especially the area under the bondwire is illuminated.


(https://www.richis-lab.de/images/transistoren/50x14.jpg)

As soon as there is a current flowing through the collector, the light shifts to the emitter area. The light there is somewhat more homogeneous, but still clearly more irregular than for example in the 2N389 (https://www.richis-lab.de/BipolarA09.htm#IR (https://www.richis-lab.de/BipolarA09.htm#IR)).

The images suggest that either the structures were fabricated irregularly or the areas have such a high resistance that there is no homogeneous current distribution. Since this is a very early silicon power transistor, such deficiencies are hardly surprising.


https://www.richis-lab.de/Bipolar29.htm#IR (https://www.richis-lab.de/Bipolar29.htm#IR)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 28, 2022, 04:19:45 am
(https://www.richis-lab.de/images/transistoren/a72x01.jpg)

Another old small transistor, a BC547. I don´t know who manufactured it.  :-//


(https://www.richis-lab.de/images/transistoren/a72x02.jpg)

(https://www.richis-lab.de/images/transistoren/a72x03.jpg)

The edge length of the die is 0,32mm. It is thus slightly larger than the Philips version. It is interesting that the outermost metal frame in the area of the base bondpad has been left out.


https://www.richis-lab.de/Bipolar44.htm#unbekannt (https://www.richis-lab.de/Bipolar44.htm#unbekannt)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 30, 2022, 07:26:01 pm
(https://www.richis-lab.de/images/transistoren/a73x01.jpg)

One more small signal transistor. The BC557 is the PNP transistor to the BC547.

I don´t know who manufactured this one but it was in the same circuit as the "unknown" BC547 (https://www.richis-lab.de/Bipolar44.htm (https://www.richis-lab.de/Bipolar44.htm)).


(https://www.richis-lab.de/images/transistoren/a73x02.jpg)

(https://www.richis-lab.de/images/transistoren/a73x03.jpg)

Hey, that´s the same die as in the BC547!


https://www.richis-lab.de/BipolarA19.htm (https://www.richis-lab.de/BipolarA19.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 06, 2023, 08:44:56 pm
We had the GD609 and the GD619, the complementary Ge transistors with the dendrites in the package:

https://www.richis-lab.de/Bipolar65.htm (https://www.richis-lab.de/Bipolar65.htm)


The emitter contact was potted with a red silicone now I have removed that stuff.


(https://www.richis-lab.de/images/transistoren/a00x07.jpg)

GD609 - The solder looks a little strange but that´s probably due to the corrosion.


(https://www.richis-lab.de/images/transistoren/a01x04.jpg)

GD619 - The emitter has a strange edged geometry...  ???


https://www.richis-lab.de/Bipolar65.htm#junction (https://www.richis-lab.de/Bipolar65.htm#junction)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 13, 2023, 08:07:17 pm
(https://www.richis-lab.de/images/transistoren/a74x01.jpg)

The  Linear Systems LS5907 is a dual JFET. It is used as an alternative to the TG-168 (https://www.richis-lab.de/K617.htm (https://www.richis-lab.de/K617.htm)) in the Keithley 617 electrometer. Linear Systems was founded in California in 1987 and according to their website has acquired processes and products from Amelco, Union Carbide, Intersil and Micro Power Systems.

The LS5907 is part of the LS5905 - LS5909 series. From the LS5906 to the LS5909, the specifications deteriorate, but the LS5905 falls out of line and offers the worst values. For the LS5907, the offset voltage between the two JFETs is a maximum of 5mV. The temperature drift of this voltage is 10µV/°C. The gate current remains below 1pA at 25°C.


(https://www.richis-lab.de/images/transistoren/a74x02.jpg)

(https://www.richis-lab.de/images/transistoren/a74x03.jpg)

This LS5907 was produced in calendar week 12 of 1991.


(https://www.richis-lab.de/images/transistoren/a74x04.jpg)

(https://www.richis-lab.de/images/transistoren/a74x05.jpg)

The potentials of the two JFETs are fed into the package in two groups. Since both JFETs are on the same die, they have very similar temperatures. In addition, production variations affect both transistors very similarly.


(https://www.richis-lab.de/images/transistoren/a74x06.jpg)

(https://www.richis-lab.de/images/transistoren/a74x07.jpg)

(https://www.richis-lab.de/images/transistoren/a74x08.jpg)

The die measures 0,53mm x 0,48mm. The gate potentials frame the corresponding drain and source regions. The upper gate electrodes run between these frames. The reason for the failure is clearly visible. A massive overload has destroyed the gate lead of the right transistor.


https://www.richis-lab.de/FET26.htm (https://www.richis-lab.de/FET26.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 15, 2023, 07:55:29 am
(https://www.richis-lab.de/images/transistoren/a75x01.jpg)

(https://www.richis-lab.de/images/transistoren/a75x02.jpg)

Some more fine Dual-JFETs?
The 2N5905 originally comes from Intersil and belongs to the 2N5902 - 2N5909 series. According to the datasheet, the 2N5905 has a maximum offset voltage of 15mV. The gate current of the 2N5905 is also the highest with a maximum of 3pA at 25°C.


(https://www.richis-lab.de/images/transistoren/a75x03.jpg)

(https://www.richis-lab.de/images/transistoren/a75x04.jpg)

The dual JFET is insulated from the housing with a ceramic plate.


(https://www.richis-lab.de/images/transistoren/a75x06.jpg)

(https://www.richis-lab.de/images/transistoren/a75x05.jpg)

The dimensions of the die are 0,42mm x 0,32mm. The JFET structures are clearly visible. A strip of the metal layer was drawn in between the two transistors.  :-//


https://www.richis-lab.de/FET27.htm (https://www.richis-lab.de/FET27.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: alayn91 on January 15, 2023, 12:56:33 pm
Hello,
Very interesting discussion.
By any chance, do you have some pictures of the NS LM194/394 ??
If no, could you provide these pictures ?
Thanks in advance.
Alain.

Title: Re: Transistors - die pictures
Post by: Noopy on January 15, 2023, 05:27:23 pm
I have to take a look into my warehouse, if there is a LM194. If not I can source one.  :-+
Title: Re: Transistors - die pictures
Post by: magic on January 15, 2023, 08:05:30 pm
Zeptobars has the LM394. It looks a bit weird.
https://zeptobars.com/en/read/National-LM394CH-super-matched-bjt
Title: Re: Transistors - die pictures
Post by: alayn91 on January 16, 2023, 08:22:58 am
Hello & thank you !
Title: Re: Transistors - die pictures
Post by: Noopy on January 16, 2023, 06:20:48 pm
(https://www.richis-lab.de/images/transistoren/a76x02.jpg)

(https://www.richis-lab.de/images/transistoren/a76x01.jpg)

Just another 2N590x. The 2N5905 we had yesterday was manufactured by Harris Semiconductor. The 2N5909 shown here was still built by Intersil. Harris Semiconductor took over Intersil in 1988.


(https://www.richis-lab.de/images/transistoren/a76x03.jpg)

(https://www.richis-lab.de/images/transistoren/a76x04.jpg)

The design is basically the same as in the 2N5905, but the ceramic carrier is smaller.


(https://www.richis-lab.de/images/transistoren/a76x05.jpg)

(https://www.richis-lab.de/images/transistoren/a76x06.jpg)

The structures of the JFETs are the same as in the 2N5905. This is not surprising. They are merely different assortments of the same design.


https://www.richis-lab.de/FET28.htm (https://www.richis-lab.de/FET28.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on January 18, 2023, 08:48:43 pm
(https://www.richis-lab.de/images/transistoren/a77x01.jpg)

Does anybody know this logo? It looks like Micro Power Systems. They sold variants of the 2N590x under the names MP590x but their M is different.


(https://www.richis-lab.de/images/transistoren/a77x02.jpg)

Unlike the 2N590x variants from Intersil and Harris Semiconductor the die here is not isolated from the package.


(https://www.richis-lab.de/images/transistoren/a77x03.jpg)

(https://www.richis-lab.de/images/transistoren/a77x04.jpg)

The dimensions of the dies are 0,72mm x 0,66mm. Structures for monitoring the manufacturing process are integrated at the upper edge. The character in the lower right corner, a S or a 5, does not allow us to draw a conclusion about the manufacturer.

An interesting artifact can be found at the right edge. Here, the passivation seems to have delaminated in a small area due to a damage on the edge.


(https://www.richis-lab.de/images/transistoren/a77x05.jpg)

It is immediately noticeable that this are not just two JFETs. Two cascode circuits have been integrated here. The small JFET J1 is the input transistor, while the larger JFET J2 shields the input transistor against the output. This reduces the effective gate drain capacitance.

The gate electrode of J1 is not only shorter, it is also thicker than the gate electrodes of J2. The different geometries are advantageous for the operation of the cascode circuit, in which the upper JFET operates in the linear region while the lower JFET operates in the saturation region.


https://www.richis-lab.de/FET29.htm (https://www.richis-lab.de/FET29.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: mister_rf on January 18, 2023, 10:04:22 pm
I have some pics of various 2N2222 transistors produced by different manufacturers.
Here’s the Motorola transistor.
MOTOROLA JAN 2N2222A

(https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/MOTOROLA_2N2222A.jpg/800px-MOTOROLA_2N2222A.jpg) (https://upload.wikimedia.org/wikipedia/commons/4/4a/MOTOROLA_2N2222A.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/2N2222.jpg/672px-2N2222.jpg) (https://upload.wikimedia.org/wikipedia/commons/a/a7/2N2222.jpg)
Title: Re: Transistors - die pictures
Post by: mister_rf on January 18, 2023, 10:10:47 pm
CRP INDUSTRIES JAN 2N2222A


(https://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/CRP_2N2222A.jpg/800px-CRP_2N2222A.jpg) (https://upload.wikimedia.org/wikipedia/commons/4/4a/MOTOROLA_2N2222A.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/3/34/CRP_INDUSTRIES_2N2222.jpg/688px-CRP_INDUSTRIES_2N2222.jpg) (https://upload.wikimedia.org/wikipedia/commons/3/34/CRP_INDUSTRIES_2N2222.jpg)
Title: Re: Transistors - die pictures
Post by: mister_rf on January 18, 2023, 10:15:26 pm
ITT Semiconductors 2N2222A

(https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/ITT_2N2222A.jpg/800px-ITT_2N2222A.jpg) (https://upload.wikimedia.org/wikipedia/commons/e/e5/ITT_2N2222A.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/ITT_Semiconductors_2N2222.jpg/640px-ITT_Semiconductors_2N2222.jpg) (https://upload.wikimedia.org/wikipedia/commons/2/2f/ITT_Semiconductors_2N2222.jpg)
Title: Re: Transistors - die pictures
Post by: mister_rf on January 18, 2023, 10:18:49 pm
National Semiconductor J 2N2222A

(https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/National_Semiconductor_2N2222A.jpg/800px-National_Semiconductor_2N2222A.jpg) (https://upload.wikimedia.org/wikipedia/commons/1/13/National_Semiconductor_2N2222A.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/0/03/National_Semiconductor_J_2N2222A.png/646px-National_Semiconductor_J_2N2222A.png) (https://upload.wikimedia.org/wikipedia/commons/0/03/National_Semiconductor_J_2N2222A.png)
Title: Re: Transistors - die pictures
Post by: mister_rf on January 18, 2023, 10:22:33 pm
IPRS BANEASA – Bucharest, Romania -  2N2222

(https://upload.wikimedia.org/wikipedia/commons/thumb/5/55/IPRS_2N2222.jpg/800px-IPRS_2N2222.jpg) (https://upload.wikimedia.org/wikipedia/commons/5/55/IPRS_2N2222.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/IPRS_BANEASA_2N2222.jpg/639px-IPRS_BANEASA_2N2222.jpg) (https://upload.wikimedia.org/wikipedia/commons/3/37/IPRS_BANEASA_2N2222.jpg)
Title: Re: Transistors - die pictures
Post by: exe on January 19, 2023, 09:27:46 pm
So... Which 2N2222 is the best? :)
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on January 19, 2023, 10:12:35 pm
2N4401 ;D

Tim
Title: Re: Transistors - die pictures
Post by: BrianHG on January 19, 2023, 10:31:51 pm
So... Which 2N2222 is the best? :)
Well, the Motorola one is a mutant.
The CRP INDUSTRIES one combs your hair.
The ITT Semiconductors one needs help.
The National Semiconductor one is intelligent.
The IPRS BANEASA one stealthily flies.
Title: Re: Transistors - die pictures
Post by: mister_rf on January 19, 2023, 10:33:33 pm
So... Which 2N2222 is the best? :)

Perhaps the question should be formulated as follows: What’s the practical difference between these transistors?  8)
It's interesting that the idea came to me when I've found 4 x 2N2222 transistors on the same board, but each has been manufactured by a different company.
Title: Re: Transistors - die pictures
Post by: David Hess on January 20, 2023, 01:41:26 pm
2N4401 ;D

I concur.

So... Which 2N2222 is the best? :)

Well, the Motorola one is a mutant.

The Motorola one shows the structure of the original 2N2222 which gave it its performance.  The others rely on better processes.

Title: Re: Transistors - die pictures
Post by: BrianHG on January 20, 2023, 02:22:35 pm
2N4401 ;D

I concur.

So... Which 2N2222 is the best? :)

Well, the Motorola one is a mutant.

The Motorola one shows the structure of the original 2N2222 which gave it its performance.  The others rely on better processes.
The 'Mutant' stood for 'Marvel's X-Men' from their comics / movie cinematic universe.
Title: Re: Transistors - die pictures
Post by: David Hess on January 20, 2023, 03:16:42 pm
Quote
So... Which 2N2222 is the best? :)

Well, the Motorola one is a mutant.

The Motorola one shows the structure of the original 2N2222 which gave it its performance.  The others rely on better processes.

The 'Mutant' stood for 'Marvel's X-Men' from their comics / movie cinematic universe.

The discussion about what made the 2N2222 unique at the time starts here:

http://www.semiconductormuseum.com/Transistors/Motorola/Haenichen/Haenichen_Page7.htm (http://www.semiconductormuseum.com/Transistors/Motorola/Haenichen/Haenichen_Page7.htm)
Title: Re: Transistors - die pictures
Post by: Noopy on February 07, 2023, 06:47:00 pm
(https://www.richis-lab.de/images/transistoren/a78x01.jpg)

(https://www.richis-lab.de/images/transistoren/a78x02.jpg)

The KCZ58 is a dual transistor built by Tesla. The maximum Vce0 is 30V, the maximum collector current is 100mA, and the power dissipation must remain below 450mW. The current gain factors range from 100 to 500, with the ratio of the two transistors given as 0,9 - 1,11. Judging from the specifications, the KCZ59 was a lower grade of the same product. The range of possible current gain factors is slightly larger at 50 - 500 and the ratio of the two transistors may range from 0,8 to 1,25.

RG probably stands for a production in July 1978. The number 1 cannot be assigned.  :-//


(https://www.richis-lab.de/images/transistoren/a78x03.jpg)

(https://www.richis-lab.de/images/transistoren/a78x04.jpg)

There are two individual transistors in the package. The collector potentials are supplied via metal sheets, which in addition serve as a support for the transistors.


(https://www.richis-lab.de/images/transistoren/a78x05.jpg)

(https://www.richis-lab.de/images/transistoren/a78x06.jpg)

(https://www.richis-lab.de/images/transistoren/a78x07.jpg)

Each transistor has an edge length of 0,59mm. It is the known structure, where a round emitter is located in a round base, which has a bulge as contact area. The square with the underlying cross-shaped structure was certainly used to check the alignment of the masks.

The right transistor seems damaged in the left area of the emitter, but works completely normally. It is probably just an impurity.


(https://www.richis-lab.de/images/transistoren/a78x08.jpg)

(https://www.richis-lab.de/images/transistoren/a78x09.jpg)

(https://www.richis-lab.de/images/transistoren/a78x10.jpg)

The base-emitter junction breaks down at -7,5V and shows the familiar glow of an avalanche breakdown. The current increases from top to bottom: 10mA, 50mA, 100mA. The uniform glow suggests that the transistor is not damaged and the artifact is just a minor contamination.


https://www.richis-lab.de/BipolarA20.htm (https://www.richis-lab.de/BipolarA20.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on February 07, 2023, 07:41:14 pm
A reversed BE can be used as a noise generator.  I wonder how much noise correlation would be if each transistor in such a pair would be used as an independent noise generator.  ???
Title: Re: Transistors - die pictures
Post by: Noopy on February 07, 2023, 07:51:17 pm
A reversed BE can be used as a noise generator.  I wonder how much noise correlation would be if each transistor in such a pair would be used as an independent noise generator.  ???

Ignoring external influences I would assume there is no correlation since it is a stochastic process. But I don´t really know...  :-//
Title: Re: Transistors - die pictures
Post by: Noopy on February 12, 2023, 09:47:24 pm
(https://www.richis-lab.de/images/transistoren/a79x01.jpg)

L6202 a famous H-bridge built by STMicroelectronics (SGS-Thomson to be honest). It´s more than a transistor but I have put it to the "special transistors".

In this Powerdip18 package, the device can carry up to 1,5Arms. Alternatively, a SO20 package is offered, but it allows just 1Arms. For higher power, a Multiwatt11 and a PowerSO20 package make it possible to conduct up to 4Arms. The peak current may increase up to 5A. The SO20 package is limited to 2A in this regard. The typical resistance of the switches is 0,3Ω. The maximum permissible supply voltage is 48V. The typical clock frequency is given in the datasheet as 30kHz, 100kHz is specified as the maximum. The L6202 ensures with a dead time of 100ns that never both switches are conductive at the same time.


(https://www.richis-lab.de/images/transistoren/a79x02.jpg)

The block diagram in the datasheet shows the construction of the L6202. The H-bridge is built with four NMOS transistors. The negative potential of the H-bridge is isolated from the ground potential, so that a shunt for current measurement can be looped in.

According to the datasheet, the NMOS transistors are switched with a gate-source voltage of 10V. However, this also means that a separate supply voltage must be generated for the two highside transistors. This voltage can be obtained from two different sources. A charge pump ensures that the highside transistors can be switched on from a longer inactive phase. If switching gets faster, the charge pump would probably not be powerful enough. For this, bootstrap capacitors must be connected to the L6202, which lift the necessary larger amounts of charge to the high potential when the H-bridge is switched. According to the datasheet, the capacitance should be at least ten times as large as the input capacitance of the transistor, which is 1nF.

Four gates can be used to switch the two sides of the H-bridge. An enable input allows to switch off all transistors. An overtemperature protection switches the H-bridge off at temperatures above 150°C. The L6202 contains a 13,5V reference voltage source which must be stabilized externally with at least 220nF. One may then load the reference with up to 2mA.


(https://www.richis-lab.de/images/transistoren/a79x03.jpg)

The six pins in the middle of the package are connected to ground. It can be seen that these pins are combined into a carrier on which the die is placed. This improves the power dissipation. Accordingly, the datasheet recommends connecting a large copper area to the six pins in the middle of the package.


(https://www.richis-lab.de/images/transistoren/a79x04.jpg)

The dimensions of the die are 5,1mm x 4,0mm. According to the datasheet, the device was manufactured with a BCD process. This allows the control circuit to be built with the benefits of bipolar and CMOS transistors, while high-performance DMOS transistors are used in the H-bridge. There are indications that the L6202 was the first device to be manufactured with a BCD process at STMicroelectronics, SGS-Thomson respectively.


(https://www.richis-lab.de/images/transistoren/a79x05.jpg)

Somewhat to the left of center, several numbers are shown on top of each other. It seems that there are two metal layers used here. In the circuit itself, however, only one metal layer can be seen. The lower number is 8065, the upper 8545. The meaning remains unclear.


(https://www.richis-lab.de/images/transistoren/a79x06.jpg)

To the right of the center, the logo of SGS Thomson and the year 1986 are shown. The string U0024 could be an internal project designation.


(https://www.richis-lab.de/images/transistoren/a79x07.jpg)

On the left edge, there are some structures that allow to monitor the imaging performance of the process. The 13 squares could indicate a mask set with 13 masks.


(https://www.richis-lab.de/images/transistoren/a79x08.jpg)

(https://www.richis-lab.de/images/transistoren/a79x10.jpg)

The interconnection of the four power transistors is clearly visible. The width of the lines is adapted to the respective local current. At first glance, the lowside transistors appear somewhat larger than the highside transistors. However, the highside transistors are slightly wider, resulting in approximately equal areas, as would be expected with four NMOS transistors. The gate potentials are fed from the top and from the bottom.


(https://www.richis-lab.de/images/transistoren/a79x09.jpg)

The control circuit is relatively clear. It is easy to see that each highside transistor is supplied from two areas. The charge pumps seem to be located in the center. Two very large, reddish areas are integrated there, which certainly represent the associated capacitances.

On the left and right edges, the bootstrap bondpads are placed respectively. In these areas is another control for the gate electrodes. Four larger elements are integrated in each of the corners. It could be that these are transistors that limit the gate-source voltage. After all, this voltage could approach the maximum permissible supply voltage of 48V.


https://www.richis-lab.de/FET30.htm (https://www.richis-lab.de/FET30.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 15, 2023, 04:12:09 am
these die photos are phenomenal! nice work Noopy!

Thank you!
I still have plenty pictures on my hard drive and a lot of parts in stock.  8)
Title: Re: Transistors - die pictures
Post by: Noopy on March 04, 2023, 02:52:17 pm
(https://www.richis-lab.de/images/transistoren/a80x01.jpg)

(https://www.richis-lab.de/images/transistoren/a80x02.jpg)

The MJE3055 is an alternative to the 2N3055 (https://www.richis-lab.de/2N3055.htm (https://www.richis-lab.de/2N3055.htm)). Here, however, the maximum permissible collector current is not 15A, but only 10A. The TO127 package is slightly larger than a TO220 package and thus allows a power dissipation of up to 90W. The MJE3055 is thus slightly less powerful than the 2N3055 in the TO3 package. In the alternative TO220 package, the MJE3055 allows just 75W. Maximum Vce is 60V, cutoff frequency is 2MHz.


(https://www.richis-lab.de/images/transistoren/a80x03.jpg)

Inside the package there is a relatively thick carrier. A silicone-like potting protects the die and bondwires.


(https://www.richis-lab.de/images/transistoren/a80x04.jpg)

The potting is easy to remove.


(https://www.richis-lab.de/images/transistoren/a80x05.jpg)

(https://www.richis-lab.de/images/transistoren/a80x06.jpg)

The dimensions of the die is 3,2mm x 2,8mm. It seems to be the same transistor that Motorola used in the 2N3055I (https://www.richis-lab.de/2N3055_10.htm (https://www.richis-lab.de/2N3055_10.htm)).


(https://www.richis-lab.de/images/transistoren/a80x07.jpg)

(https://www.richis-lab.de/images/transistoren/a80x08.jpg)

Typical for a MESA transistor, the edges are etched down, resulting in clean outer edges at the base-collector interface. The etching process has left an interesting surface texture.


(https://www.richis-lab.de/images/transistoren/a80x09.jpg)

Emitter and base form the typical structures of a power transistor. For contacting the surfaces, there are vias in the protective passivation layer, the edges of which become visible in the surface of the metal layer.


https://www.richis-lab.de/BipolarA21.htm (https://www.richis-lab.de/BipolarA21.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 06, 2023, 06:31:28 pm
(https://www.richis-lab.de/images/transistoren/a81x01.jpg)

Now the MJE2955, the complementary PNP transistor to the MJE3055. It has exactly the same specifications.


(https://www.richis-lab.de/images/transistoren/a81x02.jpg)

The mechanical construction is the same as in the MJE3055. However, much more solder seems to have been used to fix the die. The solder has spread over the carrier. A silicone-like potting was used here too.


(https://www.richis-lab.de/images/transistoren/a81x03.jpg)

(https://www.richis-lab.de/images/transistoren/a81x04.jpg)

The die is constructed in the same way as the die of the MJE3055. However, the MJE2955 being a PNP transistor is significantly larger. The dimensions are 3,6mm x 3,1mm, compared to the 3,2mm x 2,8mm of the MJE3055.


(https://www.richis-lab.de/images/transistoren/a81x05.jpg)

Unlike the MJE3055 the surface of the etched-down edges is very smooth.


(https://www.richis-lab.de/images/transistoren/a81x06.jpg)

The metal layer is slightly offset downwards compared to the other structures.


https://www.richis-lab.de/BipolarA22.htm (https://www.richis-lab.de/BipolarA22.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 31, 2023, 08:17:58 pm
(https://www.richis-lab.de/images/transistoren/a82x01.jpg)

The 2N6543 is a switching transistor which can isolate up to 400V. A collector current of 5A is constantly permissible, up to 10A is possible for a short time (1ms/10%). The base path is specified with the same current carrying capacity, so in addition to the collector current, the datasheet specifies a maximum emitter current, which can be correspondingly twice as high (10A/20A). The cut-off frequency is between 6MHz and 28MHz. At 25°C 100W can be dissipated via the housing. The characteristic values are taken from a RCA datasheet. The 2N6543 shown here was manufactured in 1980 by the American company TRW.


(https://www.richis-lab.de/images/transistoren/a82x11.jpg)

The RCA datasheet contains an SOA diagram. It clearly shows how optimization to best switching performance affects the behavior in the linear area. Just in a small range the area is limited by the maximum power dissipation. A much stronger limitation results from the very early onset of the second breakdown.


(https://www.richis-lab.de/images/transistoren/a82x02.jpg)

(https://www.richis-lab.de/images/transistoren/a82x03.jpg)

The emitter is connected to the die via two bondwires.


(https://www.richis-lab.de/images/transistoren/a82x05.jpg)

Here, the bondwires have been welded to the side of the connection pins.


(https://www.richis-lab.de/images/transistoren/a82x04.jpg)

(https://www.richis-lab.de/images/transistoren/a82x07.jpg)

The die is located on a base, which is equipped with a trench. Excess solder collects in this trench when the die is soldered on the base.


(https://www.richis-lab.de/images/transistoren/a82x09.jpg)

(https://www.richis-lab.de/images/transistoren/a82x06.jpg)

The edge length of the die is 5,1mm. Unusual is the use of two emitter areas. The lower and upper comb structures each represent an isolated emitter surface. The imprints of test needles can be seen on the metal surfaces.


(https://www.richis-lab.de/images/transistoren/a82x08.jpg)

To isolate the high voltage, there is a structure in the outer area which controls the potential distribution. Otherwise, the electric field would be too inhomogeneous and flashovers would occur at the edge of the transistor.

Between base and emitter more structures are visible than one would expect. On closer inspection, the grey areas seem to be contact areas, which are wider than the metal areas. Brown would then be the base doping and purple the emitter doping. This would also match the colors of the potential distribution.


(https://www.richis-lab.de/images/transistoren/a82x10.gif)

At a voltage of -10V, the base-emitter junction breaks down and the typical glow effect of an avalanche breakdown is seen (current levels: 20mA, 50mA, 100mA, 200mA, 500mA, 1A, 2A).


https://www.richis-lab.de/BipolarA23.htm (https://www.richis-lab.de/BipolarA23.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on March 31, 2023, 11:20:59 pm
Nice one.

Excuse this bit of pareidolia: ;D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on April 01, 2023, 03:07:53 am
Yeah, sometimes they talk to me...  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on April 03, 2023, 03:11:11 am
(https://www.richis-lab.de/images/transistoren/a83x01.jpg)

The NDUL09N150C from ON Semiconductor is a power MOSFET that can block up to 1500V. In order to provide sufficient isolation distances, the TO-3PF package has an additional plastic collar on the drain pin. A metallic cooling fin is missing. This worsens the thermal resistance (1,6°C/W), but makes assembly easier because no additional insulation layer has to be added. With a housing temperature of 25°C, the MOSFET can dissipate up to 78W. The typical Rdson is 2,2Ω. The datasheet states two different current carrying capacities. The transistor itself would allow 9A permanently, but the package limits this value to 6A. At 6A, there is already more power loss than can be sensibly dissipated via the housing. Up to 18A is permissible for a short time.


(https://www.richis-lab.de/images/transistoren/a83x02.jpg)

The die has an edge length of 8mm. The thickness is approximately 0,25mm. The source bonding area is in the centre. The connection for the gate potential is placed on the left edge. Only one bondwire was used for the source connection, but with a much thicker cross-section than for the gate connection.


(https://www.richis-lab.de/images/transistoren/a83x06.jpg)

The die is covered with a protective layer, probably polyimide. Next to the source connector is a window that appears to be for testing purposes.


(https://www.richis-lab.de/images/transistoren/a83x03.jpg)

The familiar round structures for potential control are integrated at the edge of the die so that no flashovers occur at up to 1500V.


(https://www.richis-lab.de/images/transistoren/a83x04.jpg)

(https://www.richis-lab.de/images/transistoren/a83x05.jpg)

The gate potential is conducted over a frame, around the perimeter of the active area, and makes contact at the upper and lower edges with deeper lying lines leading into the active area.

The metal surface that conducts the drain potential is connected to the underlying trench MOSFET structures via long vertical openings.


(https://www.richis-lab.de/images/transistoren/a83x07.jpg)

The layers are difficult to remove. Here, however, you can see that the gate potential is led into the MOSFET via the yellowish surfaces. From the lateral contacts, the surface has already been heavily attacked.

The drain potential contacts the MOSFET not only via the vertical strips, but also at the edges. This measure is presumably intended to ensure that the potential around the active area is always the same at all points and that there is no local excess in the electric field.


https://www.richis-lab.de/FET31.htm (https://www.richis-lab.de/FET31.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 23, 2023, 07:50:57 pm
(https://www.richis-lab.de/images/transistoren/a84x01.jpg)

The TDE1647 is a relay and lamp driver from Thomson Semiconducteurs. It blocks up to 50V and conducts up to 1A. The value to which the short-circuit current is limited can be set via an external shunt. The device also contains an overtemperature cutoff.


(https://www.richis-lab.de/images/transistoren/a84x09.jpg)

The datasheet contains a block diagram showing how the TDE1647 works. The two inputs control a differential amplifier that controls a power transistor at the output. Depending on the voltage drop across the external shunt, another transistor shunts the base current of the power transistor, limiting the output current. The overtemperature protection can sink the base current too. The square with the G possibly stands for the ground loss protection circuit that the TDE1747 includes. The TDE1747 shares a datasheet with the TDE1647.


(https://www.richis-lab.de/images/transistoren/a84x08.jpg)

The datasheet contains a complete circuit diagram of the TDE1647 / TDE1747 too. At the input is a classic differential amplifier (yellow). The current source of the differential amplifier belongs to a bias network (blue), which is based on a reference current source (cyan).

The output signal of the differential amplifier passes through two amplifier stages (pink). The actual amplifier stage consists of the Darlington pair Q6/Q9. The transistor Q5 diverts the base current of this Darlington pair when it is activated.

The grey circuit part represents the overtemperature protection. A constant potential is applied to R2. If the temperature increases, the base-emitter voltage of Q28 drops and a current flows through R10. The current mirror Q17 conducts a proportional current through D3 to Q28 and thus realises a hysteresis. At the same time, transistor Q29 becomes active, which diverts the current from current source Q15 without which the output stage switches off.

The control signal of the output transistor passes through a surprisingly complex circuit (purple). This appears to be the ground loss protection circuit of the TDE1747. If a current flows through the Darlington transistors Q6/Q9, it also flows through Q23 and activates the output stage. In the event of a ground loss, the voltage drop across this circuit is very low. Then the current path via Q25 and Q22 dominates and the current of the current source Q15 is diverted so that the output stage remains inactive.

The output stage is controlled via transistor Q18 (dark red). The output stage (red) consists of a Sziklai pair. (There is a point missing in the circuit diagram.) In the overcurrent protection (green), Q24 can dissipate the base current of the output stage.


(https://www.richis-lab.de/images/transistoren/a84x02.jpg)

The housing has six pins. The pins carrying power are grouped on the right, while the control and the ground potential are supplied on the left.


(https://www.richis-lab.de/images/transistoren/a84x03.jpg)

(https://www.richis-lab.de/images/transistoren/a84x04.jpg)

The dimensions of the die are 4,2mm x 2,9mm. The individual elements are clearly visible.

The output stage transistor consists of three areas. The widths of the lines are adapted to the local current strengths. Each area has a resistor on the emitter side, which guarantees an even current distribution. Where each emitter strip is contacted, the contour of a taper is visible in the metal layer, which represents an emitter resistor for the individual transistor. It is interesting to note that in the uppermost area, the emitter strip on the far left has been omitted.

At the upper edge there is an elongated structure. This is the driver transistor, which as a PNP transistor must be relatively large.


(https://www.richis-lab.de/images/transistoren/a84x05.jpg)

The die already bears an ST logo. Next to it, a symbol has been integrated that is reminiscent of a lighthouse. Perhaps this is an allusion to its function as a lamp driver.


(https://www.richis-lab.de/images/transistoren/a84x06.jpg)

The revisions of eight masks are shown at the bottom edge. According to this, all masks were revised once and one twice.

The numbers 1747 show that this design can also be used for the TDE1747. Analysing the circuit, it can be seen that the circuit part which probably represents the ground loss protection circuit is present and active here. This means that a TDE1747 has actually been built into this TDE1647.


(https://www.richis-lab.de/images/transistoren/a84x07.jpg)

P160 could be an internal project designation or a designation for the manufacturing process used.


https://www.richis-lab.de/BipolarA24.htm (https://www.richis-lab.de/BipolarA24.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on April 30, 2023, 07:33:16 pm
Here comes an update for the TDE1647:


(https://www.richis-lab.de/images/transistoren/a84x05.jpg)

I got the hint that the logo right of the ST logo probably show the Eifel tower. 1937 a company that later became Thomson Semiconducteurs performed the first radio transmission from the Eifel tower.


(https://www.richis-lab.de/images/transistoren/a84x10.jpg)

If you analyze the circuit on the die, you will find a few minor differences to the schematic.


(https://www.richis-lab.de/images/transistoren/a84x11.jpg)

If you redraw the schematic accordingly, you get the following picture.

The resistor R2 between the resistors R13 and R14 is missing on the die. Likewise, resistor R7 is missing in the supply line of Q23 and Q18. Instead, there is a resistor in the supply line to Q17, which is missing in the schematic. Sometimes such resistors are just undercrossings and their value is irrelevant. Here, however, it seems to be an intentional resistor.

Q6 is not supplied by Q13 in the real circuit, but by Q15. There is a diode between Q15 and Q6.

Q24, which is the overcurrent protection, owns a base resistor on the die. There is also a surprisingly large diode in the collector path. This was probably used to adjust the tripping voltage of the overcurrent protection.


https://www.richis-lab.de/BipolarA24.htm#Update (https://www.richis-lab.de/BipolarA24.htm#Update)
Title: Re: Transistors - die pictures
Post by: Noopy on May 01, 2023, 09:24:18 am
(https://www.richis-lab.de/images/transistoren/a85x01.jpg)

The TDE1737 is a relay and lamp driver like the TDE1647. While the TDE1647 contains a highside output stage, the TDE1737 has a lowside output stage. The reverse voltage is up to 50V, the current may rise up to 1A.


(https://www.richis-lab.de/images/transistoren/a85x02.jpg)

Pretty similar to the TDE1647.


(https://www.richis-lab.de/images/transistoren/a85x03.jpg)

The differential amplifier at the input (yellow) is similar to the one in the TDE1647. However, the common current source is missing here. The current through the branches is adjusted just via the transistors Q3/Q4. The bias setting (blue) and reference current sink (cyan) look the same like in the TDE1647.

The output of the differential amplifier passes two amplifier stages (pink). The second amplifier stage is reminiscent of a Darlington transistor. However, Q6 is connected as a diode. Either one wanted to provide the possibility to build up a Darlington transistor or Q6 ensures that Q9 switches off more slowly and the output stage switches on with a minimal delay. In addition, it could of course be a remnant of the TDE1647 circuit, which is quite similar to the TDE1737.

As long as the transistor Q9 is inactive, the current of the current source Q15 controls the output stage, which consists of a Darlington transistor (red). As overcurrent protection, transistor Q24 (green) diverts the base current of the output stage if too much voltage drops across the external shunt.

The overtemperature protection of the TDE1737 (grey) is based on the reference voltage of the reference current sink (cyan). If the temperature rises, the base-emitter voltage of Q18 drops and a current flows through Q18, Q21 and Q17. The current mirror Q17 then controls Q16 and diverts the base current of the output stage through it.

The remaining elements (purple) appear to perform a similar function to the ground loss protection circuit in the TDE1647. Ground loss is less critical in a lowside driver. However, the circuit could protect the TDE1737 against supply voltages that are too low to guarantee a proper functionality. Only when the voltage between Vcc and GND is high enough for D2 to conduct, Q23 diverts current from current source Q15, thus deactivating transistor Q22, which otherwise, like transistor Q16, keeps the output stage inactive.


(https://www.richis-lab.de/images/transistoren/a85x04.jpg)

(https://www.richis-lab.de/images/transistoren/a85x05.jpg)

The dimensions of the die are 2,1mm x 1,4mm. On the lower edge, a relatively large logo refers to ST Microelectronics.


(https://www.richis-lab.de/images/transistoren/a85x06.jpg)

On the upper edge there is a year which is difficult to identify. It looks like 1985.


(https://www.richis-lab.de/images/transistoren/a85x08.jpg)

In the lower left corner, the characters 1737.C are shown in the metal layer. The C could stand for a third revision of the design.


(https://www.richis-lab.de/images/transistoren/a85x07.jpg)

(https://www.richis-lab.de/images/transistoren/a85x13.jpg)

In the upper left corner the mask revisions are shown. Two masks are difficult to see, but as with the TDE1647, there are seven masks in total.


(https://www.richis-lab.de/images/transistoren/a85x09.jpg)

X057 could be an internal project designation.


(https://www.richis-lab.de/images/transistoren/a85x10.jpg)

A closer analysis of the dies reveals some minor differences to the schematic. It is also noticeable that the design is very similar to the TDE1647 in many places.


(https://www.richis-lab.de/images/transistoren/a85x11.jpg)

The most noticeable thing is that the purple circuit is missing completely. Instead, two diodes have been integrated into the collector path of the current source Q15. The additional voltage drop probably ensures that the output stage can only be controlled when the supply voltage reaches a value at which the rest of the circuit can do it´s job properly.


(https://www.richis-lab.de/images/transistoren/a85x12.jpg)

On the upper edge there is a bondpad that cannot be assigned to any function. The current source Q14 has an additional emitter whose constant current is led to a small circuit below the bondpad. There is the NPN transistor Qa and the resistor R with three taps.


(https://www.richis-lab.de/images/transistoren/a85x14.jpg)

It remains unclear what function the additional circuit has. Perhaps it enables to determine the manufacturing quality. Perhaps it is a hold-off that only has a meaningful function with a different metal layer.


https://www.richis-lab.de/BipolarA25.htm (https://www.richis-lab.de/BipolarA25.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: AnalogTodd on May 01, 2023, 06:37:21 pm
(https://www.richis-lab.de/images/transistoren/a85x01.jpg)

The TDE1737 is a relay and lamp driver like the TDE1647. While the TDE1647 contains a highside output stage, the TDE1737 has a lowside output stage. The reverse voltage is up to 50V, the current may rise up to 1A.


(https://www.richis-lab.de/images/transistoren/a85x02.jpg)

Pretty similar to the TDE1647.


(https://www.richis-lab.de/images/transistoren/a85x03.jpg)

The differential amplifier at the input (yellow) is similar to the one in the TDE1647. However, the common current source is missing here. The current through the branches is adjusted just via the transistors Q3/Q4. The bias setting (blue) and reference current sink (cyan) look the same like in the TDE1647.

The output of the differential amplifier passes two amplifier stages (pink). The second amplifier stage is reminiscent of a Darlington transistor. However, Q6 is connected as a diode. Either one wanted to provide the possibility to build up a Darlington transistor or Q6 ensures that Q9 switches off more slowly and the output stage switches on with a minimal delay. In addition, it could of course be a remnant of the TDE1647 circuit, which is quite similar to the TDE1737.

As long as the transistor Q9 is inactive, the current of the current source Q15 controls the output stage, which consists of a Darlington transistor (red). As overcurrent protection, transistor Q24 (green) diverts the base current of the output stage if too much voltage drops across the external shunt.
Looking at the circuit, diode Q6 is actually there for voltage drop without additional current gain. If you just had Q9 without the diode in series with its base, the emitter follower formed by Q5 that comes off the output of the error amplifier may not be able to turn Q9 off; the output device of the error amplifier (Q8) goes into saturation (~100mV depending on process) and you go up 0.7V from the Vbe of Q5 and will have ~0.8V at the base of Q9 no matter how hard you want to turn him off. If you made Q6/Q9 a Darlington, you could potentially have too much current gain and loop instability.
The overtemperature protection of the TDE1737 (grey) is based on the reference voltage of the reference current sink (cyan). If the temperature rises, the base-emitter voltage of Q18 drops and a current flows through Q18, Q21 and Q17. The current mirror Q17 then controls Q16 and diverts the base current of the output stage through it.

The remaining elements (purple) appear to perform a similar function to the ground loss protection circuit in the TDE1647. Ground loss is less critical in a lowside driver. However, the circuit could protect the TDE1737 against supply voltages that are too low to guarantee a proper functionality. Only when the voltage between Vcc and GND is high enough for D2 to conduct, Q23 diverts current from current source Q15, thus deactivating transistor Q22, which otherwise, like transistor Q16, keeps the output stage inactive.


(https://www.richis-lab.de/images/transistoren/a85x04.jpg)

(https://www.richis-lab.de/images/transistoren/a85x05.jpg)

The dimensions of the die are 2,1mm x 1,4mm. On the lower edge, a relatively large logo refers to ST Microelectronics.


(https://www.richis-lab.de/images/transistoren/a85x06.jpg)

On the upper edge there is a year which is difficult to identify. It looks like 1985.


(https://www.richis-lab.de/images/transistoren/a85x08.jpg)

In the lower left corner, the characters 1737.C are shown in the metal layer. The C could stand for a third revision of the design.


(https://www.richis-lab.de/images/transistoren/a85x07.jpg)

(https://www.richis-lab.de/images/transistoren/a85x13.jpg)

In the upper left corner the mask revisions are shown. Two masks are difficult to see, but as with the TDE1647, there are seven masks in total.


(https://www.richis-lab.de/images/transistoren/a85x09.jpg)

X057 could be an internal project designation.


(https://www.richis-lab.de/images/transistoren/a85x10.jpg)

A closer analysis of the dies reveals some minor differences to the schematic. It is also noticeable that the design is very similar to the TDE1647 in many places.


(https://www.richis-lab.de/images/transistoren/a85x11.jpg)

The most noticeable thing is that the purple circuit is missing completely. Instead, two diodes have been integrated into the collector path of the current source Q15. The additional voltage drop probably ensures that the output stage can only be controlled when the supply voltage reaches a value at which the rest of the circuit can do it´s job properly.


(https://www.richis-lab.de/images/transistoren/a85x12.jpg)
The way I look at this is operating voltage range. Diode D2 is a Zener, so if you look at the currents from Q15 you will see one goes to drive the output transistor, one goes to Q22 base and Q23 collector, and the last goes through D2 to the base of Q23. Consider the voltage across Vce(sat) of Q15 in series with the D2 Zener voltage (likely 5.5-6V range) and Vbe of Q23: until this voltage is high enough, D2 will not conduct and Q22 will be on, holding off the output. Now, when you change to the two diodes just in series with Q15, it only takes the four diode drops plus the Vce(sat) of Q15 to run, so the part will turn on at a lower input voltage.

Because of this, the circuit with D2 in it will not run until you have VCC at somewhere around 6-7V. This will be fine when running with a 12V supply, but not workable for 5V supplies or lower. With the two diodes, the circuit will work down at much lower voltages. The relay or lamp can still be tied to a higher voltage rail, but the part can be run from a 5V rail.
On the upper edge there is a bondpad that cannot be assigned to any function. The current source Q14 has an additional emitter whose constant current is led to a small circuit below the bondpad. There is the NPN transistor Qa and the resistor R with three taps.


(https://www.richis-lab.de/images/transistoren/a85x14.jpg)

It remains unclear what function the additional circuit has. Perhaps it enables to determine the manufacturing quality. Perhaps it is a hold-off that only has a meaningful function with a different metal layer.


https://www.richis-lab.de/BipolarA25.htm (https://www.richis-lab.de/BipolarA25.htm)

 :-/O
Another possibility is that it is a function that is included in a different product where the pin is used as well? As suggested, with a different metal layer, this could be added into the circuit. Maybe it was a way to add hysteresis to the part? Considering it is right next to the non-inverting input (right where you would want to introduce hysteresis), that could be a useful bit.
Title: Re: Transistors - die pictures
Post by: Noopy on May 01, 2023, 08:48:45 pm
I agree with you.
Thanks for your input.
:-+
Title: Re: Transistors - die pictures
Post by: Noopy on May 10, 2023, 06:11:45 pm
(https://www.richis-lab.de/images/transistoren/a88x01.jpg)

The RCA CA3045 is a transistor array with five transistors. The maximum allowable collector-emitter voltage is at least 15V. Collector currents up to 10mA are specified. By integrating the transistors on one die, the base-emitter voltages differ by a maximum of 5mV, typically just 0,45mV. Typical applications are high frequency applications up to 120MHz.

The transistor array is housed in a somewhat unusual ceramic package with a welded round lid. It allows an operating temperature range of -55°C to 125°C. A sintered ceramic package was also available under the designation CA3045F. An epoxy package was available with the completely different name CA3046. Another variant was the CA3045L, in a so-called beam-lead package that flat terminals can be welded into a circuit.


(https://www.richis-lab.de/images/transistoren/a88x05.jpg)

The datasheet shows the wiring of the transistors. The emitter of transistor Q5 is connected to the substrate. The transistors Q1 and Q2 are connected as a differential amplifiers.


(https://www.richis-lab.de/images/transistoren/a88x02.jpg)

The transistor array is located under the round lid in a round recess.


(https://www.richis-lab.de/images/transistoren/a88x03.jpg)

(https://www.richis-lab.de/images/transistoren/a88x04.jpg)

The die has an edge length of 1,0mm. The round structure on the left edge makes it possible to check the alignment of the masks against each other. 5457 is most likely the internal project designation.

Pin 1 can be identified by the round bondpad. Pin 13, located in the lower left corner, obviously contacts the substrate directly there, as there is no isolation structure under this bondpad.

There are six transistors on the die with the well known standard structure. A C-shaped contact area ties the collector area to a pin. A base area is inserted into the collector area, which in turn contains the emitter area.

The die with the six transistors has been used with different metal layer for different circuits. One variation is the diode array CA3039 with six diodes represented by the base-emitter paths of the transistors (https://www.richis-lab.de/Diode11.htm (https://www.richis-lab.de/Diode11.htm)).


(https://www.richis-lab.de/images/transistoren/a87x01.jpg)

Here you can see another CA3045 transistor array.


(https://www.richis-lab.de/images/transistoren/a87x02.jpg)

The design of the die is very similar to the first transistor array, but there are two small differences. The base wires of the two left transistors in the upper row is not diagonal, but wired in an 90° angle. In addition the 5 in the designation is shifted down a bit.


(https://www.richis-lab.de/images/transistoren/a87x03.jpg)

The manufacturing quality seems a bit worse than on the first CA3045. With a slightly different illumination, scratches can be seen that extend over the entire surface. The scratches are not on the surface or in the metal layer, but are located deeper.

The right edge was either uncleanly separated from the wafer or damaged during installation in the case.


(https://www.richis-lab.de/images/transistoren/a86x01.jpg)

Here you can see another CA3045 with a clearly different housing. The labeling is on the ceramic body. The marking for pin 1 is also printed and not metallized. This is certainly due to the fact that the contacts on the side have no metallization too. The pins are led into the housing.


(https://www.richis-lab.de/images/transistoren/a86x02.jpg)

In this package the design of the second CA3045 can be found. Here, too, the leading 5 of the designation is placed a bit lower.


https://www.richis-lab.de/BipolarA26.htm (https://www.richis-lab.de/BipolarA26.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 20, 2023, 05:57:54 pm
(https://www.richis-lab.de/images/transistoren/a89x01.jpg)

The logo on this power transistor shows that it was manufactured by SGS ATES. However, no information can be found regarding the name IBM458. It can be assumed that this is a transistor that was used in an IBM system. Like Hewlett-Packard, IBM had their own designations printed on their components.


(https://www.richis-lab.de/images/transistoren/a89x02.jpg)

(https://www.richis-lab.de/images/transistoren/a89x08.jpg)

The transistor is located on a round element which was soldered onto a large heatspreader. For contacting the emitter, two bondwires were used and thus the same wire diameter could be used for base and emitter.


(https://www.richis-lab.de/images/transistoren/a89x03.jpg)

The die is protected by a potting material. The black color of the potting material is rather unusual.


(https://www.richis-lab.de/images/transistoren/a89x04.jpg)

The potting is hard to remove, but in the end i managed to clean the die sufficiently.


(https://www.richis-lab.de/images/transistoren/a89x05.jpg)

The edge length of the die is 4,1mm. In the bond area of the emitter, you can see that one of three connections failed. One reason may have been that this contact was largely placed outside the bond area.

As usual, the emitter area is located inside the base area, with both areas interlocking. What is unusual, however, is the additional frame that is connected to the base potential at the associated bondpad. It is routed around the perimeter of the transistor but is isolated from the active base area. It could be that this is a potential steering at the edge. Perhaps there was a danger that the local base potential would become so inhomogeneous due to the current distribution that the transistor would break down at particularly stressful operating points.


(https://www.richis-lab.de/images/transistoren/a89x07.jpg)

There is a round, dark spot in the base bond area for which no explanation can be found.


(https://www.richis-lab.de/images/transistoren/a89x06.jpg)

The base-emitter junction is clearly visible. The additional edges right next to the metal surfaces are most likely the openings through which the metal layer contacts the semiconductor.


https://www.richis-lab.de/BipolarA27.htm (https://www.richis-lab.de/BipolarA27.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 20, 2023, 05:59:04 pm
(https://www.richis-lab.de/images/transistoren/a90x01.jpg)

The IBM459 built by SGS ATES is another custom labeled power transistor. No specifications can be found for this component either.


(https://www.richis-lab.de/images/transistoren/a90x02.jpg)

(https://www.richis-lab.de/images/transistoren/a90x03.jpg)

It turns out that the construction is similar to the IBM485. The surfaces show a slightly different color and there is a small blind hole in the base plate of the case underneath the hole in the heatspreader. Also, the bushings for the pins look slightly different. A little less potting was used here, so you can see the edges of the die in the surface.


(https://www.richis-lab.de/images/transistoren/a90x04.jpg)

Optically it is the same transistor as in the IBM485. The additional base ring is slightly wider and the bond area of the emitter is slightly larger. However, this can be explained by different production lines or different revisions of the design.


https://www.richis-lab.de/BipolarA28.htm (https://www.richis-lab.de/BipolarA28.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 20, 2023, 06:00:20 pm
(https://www.richis-lab.de/images/transistoren/a91x01.jpg)

The IBM487 is another custom labeled power transistor. No specifications can be found for this component either.


(https://www.richis-lab.de/images/transistoren/a91x02.jpg)

(https://www.richis-lab.de/images/transistoren/a91x03.jpg)

The inside of the transistor appears somewhat discolored. The reason for this could be corrosion effects or a thermal overload. In contrast to the IBM458 and the IBM459, bondwires with different diameters were used here, so that one bondwire was enough for the emitter.


(https://www.richis-lab.de/images/transistoren/a91x04.jpg)

The design is similar to the IBM458 and the IBM459.


https://www.richis-lab.de/BipolarA29.htm (https://www.richis-lab.de/BipolarA29.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 25, 2023, 06:31:01 pm
(https://www.richis-lab.de/images/transistoren/a92x01.jpg)

The SMD code J6 stands for the NPN transistor S9014 built by BL Galaxy Electrical. BL Galaxy Electrical is a Chinese manufacturer of less complex semiconductors such as diodes and transistors. The company is part of Changzhou Galaxy Electrical.

The S9014 blocks up to 45V. The maximum collector current is specified as 100mA. With a collector current of 1mA, the current gain may be in a very wide range between 200 and 1000. For this reason, the datasheet specifies two grades. The L category contains the gain factors 200-450 and the H category contains the gain factors 450-1000. The cut-off frequency is 150MHz.


(https://www.richis-lab.de/images/transistoren/a92x02.jpg)

(https://www.richis-lab.de/images/transistoren/a92x03.jpg)

The edge length of the die is just 0,24mm. The emitter surface and the surrounding base contact are clearly visible.


https://www.richis-lab.de/BipolarA30.htm (https://www.richis-lab.de/BipolarA30.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on May 28, 2023, 08:14:03 pm
(https://www.richis-lab.de/images/transistoren/a93x01.jpg)

The SMD code 2A stands for the PNP transistor MMBT3906, which is produced by several manufacturers. The device shown here is from the DT8380 IR thermometer (https://www.richis-lab.de/DT8380.htm (https://www.richis-lab.de/DT8380.htm)). The components used there suggest that in this case the manufacturer is BL Galaxy Electrical.

The MMBT3906 blocks up to 40V. The current carrying capacity is specified as 100mA. With a collector current of 10mA, the current gain is typically 300, but at least 100. The cutoff frequency is at least 250MHz.


(https://www.richis-lab.de/images/transistoren/a93x02.jpg)

(https://www.richis-lab.de/images/transistoren/a93x03.jpg)

The edge length of the die is 0,28mm. The emitter and the surrounding base contact are clearly visible.


(https://www.richis-lab.de/images/transistoren/a93x04.jpg)

The comparison with a CR2032 coin cell and another SOT23 component gives a feeling for the size of the die.


https://www.richis-lab.de/BipolarA31.htm (https://www.richis-lab.de/BipolarA31.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on May 28, 2023, 08:28:57 pm
Omg, how they cut the waffer? It's like a sand particle.
Title: Re: Transistors - die pictures
Post by: Noopy on May 28, 2023, 08:36:48 pm
Think about me peeling this tiny thing out of a black block of burned epoxy.
After that there is some cleaning and putting it in front of the camera in the right direction.  ;D
Title: Re: Transistors - die pictures
Post by: SilverSolder on May 29, 2023, 02:14:38 am
Think about me peeling this tiny thing out of a black block of burned epoxy.
After that there is some cleaning and putting it in front of the camera in the right direction.  ;D

LOL that makes bulding a ship in a bottle seem like blacksmith work! :D
Title: Re: Transistors - die pictures
Post by: Noopy on June 06, 2023, 06:25:07 pm
(https://www.richis-lab.de/images/transistoren/a94x01.jpg)

The SMD code 1AM stands for the bipolar transistor MMBT3904. This transistor is produced by various manufacturers. It remains unclear which manufacturer made this transistor.

The blocking voltage is specified with 40V. The maximum collector current is 200mA constant, 900mA peak. The current gain is typically 300 and the cut-off frequency is at least 300MHz.


(https://www.richis-lab.de/images/transistoren/a94x02.jpg)

(https://www.richis-lab.de/images/transistoren/a94x03.jpg)

The edge length of the die is 0,27mm. This makes the die the same size as most simple small signal transistors. In such transistors, simple designs are usually found in which an emitter area is integrated into a base area. Here, on the other hand, two base areas have been structured, each containing three narrow emitter areas.


https://www.richis-lab.de/BipolarA32.htm (https://www.richis-lab.de/BipolarA32.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 06, 2023, 08:12:13 pm
(https://www.richis-lab.de/images/transistoren/a94x01.jpg)

https://datasheet.lcsc.com/lcsc/2207041900_Jiangsu-Changjing-Electronics-Technology-Co---Ltd--MMBT3904_C20526.pdf (https://datasheet.lcsc.com/lcsc/2207041900_Jiangsu-Changjing-Electronics-Technology-Co---Ltd--MMBT3904_C20526.pdf)

Jiangsu Changjing Electronics, OF COURSE!  ;D
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 07, 2023, 01:04:13 am
Huh, and fT isn't higher? Also their fT curve doesn't meet the minimum? :-DD

...Hmm interesting, few others have a curve but one that does (onsemi) also shows just under 300MHz ...at Vce = 1V?! Weird, go figure. :D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on June 07, 2023, 03:06:53 am
Huh, and fT isn't higher? Also their fT curve doesn't meet the minimum? :-DD

...Hmm interesting, few others have a curve but one that does (onsemi) also shows just under 300MHz ...at Vce = 1V?! Weird, go figure. :D

Due to the structures I also expected superior specifications.  :-//
Perhaps they have a worse process (quality) and compensate that with a finer structure because it is easier or cheaper for them.  :-//
Title: Re: Transistors - die pictures
Post by: bdunham7 on June 07, 2023, 03:37:27 am
The edge length of the die is 0,27mm. This makes the die the same size as most simple small signal transistors. In such transistors, simple designs are usually found in which an emitter area is integrated into a base area. Here, on the other hand, two base areas have been structured, each containing three narrow emitter areas.

As always, thank you for posting these.  I'm trying to figure out exactly what each part actually is.  Looking at the second picture, what exactly do the two green squares represent?  Is that the P-type base material?
Title: Re: Transistors - die pictures
Post by: Noopy on June 07, 2023, 03:49:11 am
The edge length of the die is 0,27mm. This makes the die the same size as most simple small signal transistors. In such transistors, simple designs are usually found in which an emitter area is integrated into a base area. Here, on the other hand, two base areas have been structured, each containing three narrow emitter areas.

As always, thank you for posting these.  I'm trying to figure out exactly what each part actually is.  Looking at the second picture, what exactly do the two green squares represent?  Is that the P-type base material?

Yes, the two green squares are base material (p).
In the first picture you can see the narrow red areas that are emitter material (n+).
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 07, 2023, 09:17:59 am
I wonder what they're doing then... surely not just lower material purity, or sub-par diffusion or epitaxy.  The former would affect hFE at low Ic, and the latter (or both really) would affect Vcbo and Vebo.  Oh hey, I wonder if Vebo is measurable on that yet--?  May be able to get one of your favorite avalanche glow shots.  Although with so little power dissipation of a loose grain-of-sand die, maybe you'll have a hard time getting enough exposure to see it? :-DD  (Nevermind the difficulty probing it, which, I would guess at best might be done with some fiddly cats-whiskers.)

Tim
Title: Re: Transistors - die pictures
Post by: exe on June 07, 2023, 06:56:52 pm
I don't trust much datasheets for jellybean stuff. I've seen several times that Chinese datasheets are word-by-word copy of other datasheets for stuff like opamps and transistors.

For example, identical datasheets (except logo) from two different vendors:
- https://datasheet.lcsc.com/lcsc/2204201445_HGSEMI-NE5532N_C2987282.pdf (https://datasheet.lcsc.com/lcsc/2204201445_HGSEMI-NE5532N_C2987282.pdf)
- https://datasheet.lcsc.com/lcsc/2210091830_Slkor-SLKORMICRO-Elec--NE5532S_C5186033.pdf (https://datasheet.lcsc.com/lcsc/2210091830_Slkor-SLKORMICRO-Elec--NE5532S_C5186033.pdf)

What makes me very suspicious is that their numbers 1:1 match with TI datasheet: https://datasheet.lcsc.com/lcsc/2005151136_Texas-Instruments-NE5532ADR_C529290.pdf (https://datasheet.lcsc.com/lcsc/2005151136_Texas-Instruments-NE5532ADR_C529290.pdf) .

An interesting detail: Chinese DS provide phase and gain plots which are not present in others' datasheets. But of poor quality, like a copy of a bad copy. Very suspicious.

Also, I onced got a product change notification from mouser about one jfet. They completely changed device geometry: https://www.mouser.com/PCN/Central_Semiconductor_PCN165_(3).pdf (https://www.mouser.com/PCN/Central_Semiconductor_PCN165_(3).pdf) . Later they changed geometry back (though some parameters differ): https://www.mouser.com/PCN/Central_Semiconductor_PCN202.pdf (https://www.mouser.com/PCN/Central_Semiconductor_PCN202.pdf) . And it's still the same part number (and perhaps, same number in DS, though I can't find an old revision).  This makes me thinking that datasheets for cheap stuff are pretty "generic".

Your thoughts, gentlemen?
Title: Re: Transistors - die pictures
Post by: Noopy on June 07, 2023, 07:36:04 pm
It´s impossible for me to contact this tiny thing of semiconductor! No way!  ;D

And yes, datasheets often lie or don´t tell you everything.
Perhaps this transistor die is much better than a MMBT3904 and they just have put it into a MMBT3904 package because they needed MMBT3904 and had a lot of these dies in stock...  :-//
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 07, 2023, 08:58:30 pm
Well stuff like 2N3904 are JEDEC registered, so, to the extent JEDEC still controls these parts, they are required to put in those same basic parameters, and meet them.  I don't know what the actual rules if any are, as far as minimum set of parameters, or limitations on additional ones.

Also not sure about variants: MMBT3904 is only a coincidence, not a JEDEC part (well, unless it is, I don't know, but I at least thought the MMBT nomenclature was originally just a Motorola thing).  There are package variants already, like PN2222 vs. 2N2222, or 2N7002 (SOT-23 is used by JEDEC, they're not at all, all THT parts!) vs. 2N7000.

(There's very little JEDEC stuff out there, I imagine partly for historical reasons (much of their work is ancient history at this point) and because of obscurity (mainly semi mfgs really need to know this stuff, as well as actual IP protection / licensing / purchase fees / whatever).  So I don't know a lot of particulars about this, and it doesn't really matter for the most part, assumptions will do well enough.)

Anyway, as far as second-sourcing, the easiest way to sell your parts is to specify them as the originals were specified.  Copy the min/max parameters verbatim, and work to match them as well as is possible (or reasonable).  Maybe lying about some parameters is "okay" (strictly in the business sense, not engineering!), but preferably the typicals are characterized and listed earnestly, and maybe they vary a bit from the originals but for typ that's okay.

Saw one example the other day,
http://file.3peakic.com.cn:8080/product/Datasheet_LM2903A-LM2901A.pdf (http://file.3peakic.com.cn:8080/product/Datasheet_LM2903A-LM2901A.pdf)
Almost certainly a 100% CMOS version, NOT a drop-in equivalent; but looks reasonably useful, and compatible in a lot of applications.  Naming it identically is disingenuous and I'm sure will catch some off guard.

Tim
Title: Re: Transistors - die pictures
Post by: magic on June 07, 2023, 09:21:57 pm
What makes me very suspicious is that their numbers 1:1 match with TI datasheet: https://datasheet.lcsc.com/lcsc/2005151136_Texas-Instruments-NE5532ADR_C529290.pdf (https://datasheet.lcsc.com/lcsc/2005151136_Texas-Instruments-NE5532ADR_C529290.pdf) .

An interesting detail: Chinese DS provide phase and gain plots which are not present in others' datasheets. But of poor quality, like a copy of a bad copy. Very suspicious.
But they don't match the TI datasheet exactly. There are differences such as slew rate and supply current (which also seems specified per channel rather than per package) and errors - their 30nA typical Ibias spec looks unilkely, for example.

The plots are similar to NJM5532 and may have been stolen from there. Plots were also present in Philips, Signetics, Raytheon, possibly others. TI sucks.

I wouldn't trust Chinese datasheets either ;)
Title: Re: Transistors - die pictures
Post by: Noopy on June 08, 2023, 02:59:43 am
Anyway, as far as second-sourcing, the easiest way to sell your parts is to specify them as the originals were specified.  Copy the min/max parameters verbatim, and work to match them as well as is possible (or reasonable).  Maybe lying about some parameters is "okay" (strictly in the business sense, not engineering!), but preferably the typicals are characterized and listed earnestly, and maybe they vary a bit from the originals but for typ that's okay.

Saw one example the other day,
http://file.3peakic.com.cn:8080/product/Datasheet_LM2903A-LM2901A.pdf (http://file.3peakic.com.cn:8080/product/Datasheet_LM2903A-LM2901A.pdf)
Almost certainly a 100% CMOS version, NOT a drop-in equivalent; but looks reasonably useful, and compatible in a lot of applications.  Naming it identically is disingenuous and I'm sure will catch some off guard.

I agree with you!  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on June 11, 2023, 07:06:58 pm
(https://www.richis-lab.de/images/transistoren/a95x01.jpg)

The PNP transistor MJ15004 is the complementary type to the MJ15003. The two transistors are optimized for linear operation. The MJ15004 blocks up to 140V and conducts up to 20A (collector) and 25A (emitter) respectively. Up to 250W of power dissipation can be dissipated through the package with its thermal resistance of 0,7°C/W. The cut-off frequency is at least 2MHz. The present model is from Inchange Semiconductor.

I had two components that failed due to oscillations in the same application, a linear regulated power supply.


(https://www.richis-lab.de/images/transistoren/a95x02.jpg)

(https://www.richis-lab.de/images/transistoren/a95x03.jpg)

In the case there is a large heatspreader. The die is protected with a white potting, which is often found in Chinese TO packages. The bondwire of the emitter is lager than for the base.


(https://www.richis-lab.de/images/transistoren/a95x04.jpg)

The white potting hides the massive damage to the transistor. A closer look reveals that hot particles have been ejected from the side. These have settled on the heatspreader and the lateral case wall.


(https://www.richis-lab.de/images/transistoren/a95x05.jpg)

There is a dark rupture on the outer edge of the potting. According to the discolorations on the heatspreader, an arc may have burned there.


(https://www.richis-lab.de/images/transistoren/a95x06.jpg)

The die has an edge length of 6,1mm. The silicon-like potting is hard to remove. There is a crater where the bondwire contacted the emitter.


(https://www.richis-lab.de/images/transistoren/a95x07.jpg)

The current flow through the defective transistor has melted a crater into the silicon that extends to the heatspreader.


(https://www.richis-lab.de/images/transistoren/a95x08.jpg)

After further cleaning, it becomes clear that the transistor has a perforated emitter. The emitter completely covers the base and the contacting of the base takes place via round openings in the emitter layer. The large number of distributed base contacts ensures a very low-resistance connection. This allows the free charge carriers to be eliminated more quickly, thus increasing the switching speed. Further advantages are a low saturation voltage, a relatively constant gain factor even with increasing current and a comparatively late onset of avalanche breakdown (second breakdown).

Current flow across the emitter path has melted the metal layer outside the crater. The lower and upper edges of the image show that where the conductor is not completely melted the metal layer in the area of the round contacts has deformed.


(https://www.richis-lab.de/images/transistoren/a95x09.jpg)

As with the BUX22 (https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)) a surprising number of edges are found in the area of the base contacts. One could think that just two rings should be seen, the break-through through the passivation layer and the break-through through the emitter layer. Apparently, the contact areas have a more complex structure. Unfortunately, there is very little information about the exact structure of transistors with perforated emitter.


(https://www.richis-lab.de/images/transistoren/a95x10.jpg)

Discoloration on the side of the die (yellow) shows how high the local heat generation was. This also resulted in the silicon cracking (red).


(https://www.richis-lab.de/images/transistoren/a95x11.jpg)

The crack becomes visible one more time in the lower area of the transistor.


(https://www.richis-lab.de/images/transistoren/a96x01.jpg)

(https://www.richis-lab.de/images/transistoren/a96x02.jpg)

The second MJ15004 has an identical design.


(https://www.richis-lab.de/images/transistoren/a96x03.jpg)

Here, too, there is discoloration on the heatspreader in the same area, where hot material has escaped through a crack in the potting (red).


(https://www.richis-lab.de/images/transistoren/a96x04.jpg)

Removing the silicone also reveals massive damage in the contact area of the emitter.


(https://www.richis-lab.de/images/transistoren/a96x05.jpg)

Compared to the upper transistor, the destruction is not as advanced here. The metal layer has melted and the silicon seems to have suffered a bit, but no crater has formed.


https://www.richis-lab.de/BipolarA33.htm (https://www.richis-lab.de/BipolarA33.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on June 16, 2023, 07:56:15 pm
(https://www.richis-lab.de/images/transistoren/a97x01.jpg)

The SCT2450KE is a silicon carbide MOSFET built by Rohm. The transistor blocks up to 1200V and conducts permanently up to 10A. A peak current of 25A is specified. The typical resistance is 450mΩ. Up to 85W can be dissipated through the TO-247 package. The maximum junction temperature is specified as 185°C.

SiC MOSFETs have relatively small output capacitances, allowing low-loss turn-off. For the SCT2450KE, 21pF is specified. The typical turn-off time is 38ns. However, the small capacitances and fast switching increase the risk of high-frequency interference.


(https://www.richis-lab.de/images/transistoren/a97x02.jpg)

(https://www.richis-lab.de/images/transistoren/a97x03.jpg)

The die is covered with a polyimide layer that is difficult to remove. However, the relevant structures can be seen well. The left bondwire carries the source potential, which is distributed to the individual small MOSFET cells via a metal layer. The contacts to these cells are formed in the surface of the metal layer. The right bondwire supplies the gate potential, which is distributed over the right, the upper and the lower side.


(https://www.richis-lab.de/images/transistoren/a97x11.jpg)

The die of the SCT2450KE (1200V / 10A / 0.45Ω) is just 2,0mm x 1,8mm in size. In comparison, the silicon MOSFET STP3NB100FP (https://www.richis-lab.de/FET15.htm (https://www.richis-lab.de/FET15.htm) / 1000V / 3A / 5.3Ω) is already significantly larger: 3,9mm x 3,7mm, despite its poorer specifications. In contrast, the die of the NDUL09N150C (https://www.richis-lab.de/FET31.htm (https://www.richis-lab.de/FET31.htm) / 1500V / 9A / 2.2Ω) is once again significantly larger with an edge length of 8mm. Not only is the active area smaller in the SCT2450KE, but the edge structure, which is a potential control, could also be made very slim.


(https://www.richis-lab.de/images/transistoren/a97x04.jpg)

Unlike silicon, silicon carbide is transparent in the visible wavelength range. The metallization on the back of the transistor is chipped off at one point. There you can see the structure of the metallization on the front side through the substrate.


(https://www.richis-lab.de/images/transistoren/a97x09.jpg)

(https://www.richis-lab.de/images/transistoren/a97x05.jpg)

If the upper metal layer is removed with hydrochloric acid, the last coarse impurities disappear.


(https://www.richis-lab.de/images/transistoren/a97x06.jpg)

In detail, you can see the elongated contact from the gate potential to the gate layer that appears pink. From the bondpad, this contact area transitions into the frame structure that distributes the gate potential across the die. The outer frame is again connected to the source potential and provides a uniform potential in the outer area.


(https://www.richis-lab.de/images/transistoren/a97x07.jpg)

Silicon carbide offers a higher dielectric strength than silicon. Accordingly, the SCT2450KE has just a small edge area despite the high reverse voltage of 1000V. A single frame structure was sufficient to control the potential slope.


(https://www.richis-lab.de/images/transistoren/a97x08.jpg)

Viewed from above, the material also appears translucent, but cloudy.


(https://www.richis-lab.de/images/transistoren/a97x10.jpg)

However, if the focal point is chosen differently, it becomes apparent that the material is definitely transparent from above as well.


https://www.richis-lab.de/FET32.htm (https://www.richis-lab.de/FET32.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on June 17, 2023, 06:04:08 am
Very cool!  AFAIK, SiC are currently not Superjunction, just traditional planar stripe VDMOS or whatever.  The top grid pattern presumably is source connections (vias) dipping down to the die surface, through a grid (square mesh?) of gate connections.  Analogous to ye olde HEXFETs, as far as the top interconnect goes.  But with a square grid, and I assume a vertical trench structure below.  It's not clear if the FET cells would also be on a square grid, or are just stripes the whole width.

The size comparison is particularly apt, as the Si chips are also traditional planar technology -- which puts them at particular disadvantage at the higher voltage ratings.  For that technology, specific Rds(on) scaled something like Vds^2.2.

Thanks to the high breakdown field strength, comparable geometry (e.g. junction depletion widths) would give more like a 100V rating in Si, but more like 1000V in SiC.  That's basically a IRF520!

Oh! I don't suppose that's still working to some extent?  Maybe not after the acid dip, but, I wonder if the body diode glows in forward bias? >:D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on June 17, 2023, 06:05:45 am
How is the SCT2450KE bonded to its package? I didn't see a leadframe.

There was a normal leadframe, nothing special. The die just didn't remain on the leadframe.
Title: Re: Transistors - die pictures
Post by: Noopy on June 17, 2023, 06:22:25 am
Very cool!  AFAIK, SiC are currently not Superjunction, just traditional planar stripe VDMOS or whatever.  The top grid pattern presumably is source connections (vias) dipping down to the die surface, through a grid (square mesh?) of gate connections.  Analogous to ye olde HEXFETs, as far as the top interconnect goes.  But with a square grid, and I assume a vertical trench structure below.  It's not clear if the FET cells would also be on a square grid, or are just stripes the whole width.

I agree with your interpretation.  :-+
But I don´t know if they even use trenches in SiC. Would be nice to have but I don´t know if that is already possible with SiC technology.


The size comparison is particularly apt, as the Si chips are also traditional planar technology -- which puts them at particular disadvantage at the higher voltage ratings.  For that technology, specific Rds(on) scaled something like Vds^2.2.

Thanks to the high breakdown field strength, comparable geometry (e.g. junction depletion widths) would give more like a 100V rating in Si, but more like 1000V in SiC.  That's basically a IRF520!

 :-+


Oh! I don't suppose that's still working to some extent?  Maybe not after the acid dip, but, I wonder if the body diode glows in forward bias? >:D

Well after furnace decapping lighting a junction should still be possible (like here: https://www.richis-lab.de/FET05.htm (https://www.richis-lab.de/FET05.htm)).
And of course I tried that with the SCT2450KE too. Unfortunately nothing happened. Perhaps I didn´t get good contact. Perhaps there was some major damage. I don´t know. I was very sad...  :'( ;D
Title: Re: Transistors - die pictures
Post by: Noopy on July 04, 2023, 08:35:55 pm
(https://www.richis-lab.de/images/transistoren/a98x01.jpg)

A new 2N3055! This one is built by Sescosem.
Since I didn´t find a datasheet I don´t know what TVCD means.  :-//


(https://www.richis-lab.de/images/transistoren/a98x02.jpg)

(https://www.richis-lab.de/images/transistoren/a98x03.jpg)

There is a heatspreader in the package that takes up almost the entire area. A relatively large amount of solder was used to attach the die to the heatspreader.


(https://www.richis-lab.de/images/transistoren/a98x04.jpg)

(https://www.richis-lab.de/images/transistoren/a98x06.jpg)

The transistor has a MESA structure and is covered with a transparent protective coating. At the lower edge you can see that it wasn´t cut out of the wafer a clean as they do it today.


(https://www.richis-lab.de/images/transistoren/a98x05.jpg)

The MESA structure is clearly visible.


(https://www.richis-lab.de/images/transistoren/a98x07.jpg)

There are some relatively deep holes on the MESA edge. The etching process of the MESA structure does not seem to have been very accurate.


(https://www.richis-lab.de/images/transistoren/a98x08.jpg)

In the upper left corner you can see an impressive manufacturing defect. A large trench has formed parallel to the MESA structure. The trench is so close to the active area that the metal layer in this corner became very narrow.


(https://www.richis-lab.de/images/transistoren/a98x09.jpg)

The surface of the transistor has no unusual structures. Under the outer metal surface, the contact area to the silicon seems to be somewhat larger than necessary. Towards the base-emitter interface, its edge can be seen a little.


(https://www.richis-lab.de/images/transistoren/a98x10.gif)

For an epitaxial transistor, the breakdown of the base-emitter path occurs relatively late at -15V. This can probably be explained by the fact that this is an early model of an epitaxial transistor. Compared to modern transistors with their much more clean processes, the concentration of dopants had to be chosen lower in the past.

In the picture above, the current increases as follows: 5mA, 10mA, 20mA, 30mA, 40mA, 50mA, 100mA, 200mA, 300mA. The luminous effect is distributed fairly evenly across the junction.


(https://www.richis-lab.de/images/transistoren/a98x11.gif)

Operation in the breakdown shows a strikingly large disturbance in the junction. The current flow you can see here is 100mA, 200mA, 300mA, 400mA, 500mA.


(https://www.richis-lab.de/images/transistoren/a98x12.jpg)

The semi-circular glow forms around a round disturbance near the junction. Many optical artefacts are merely impurities on the surface of the transistor or the protective coating. Here, however, there is actually a disturbance in the active area. It is impossible to be sure what is happening in this area. In any case, the junction has expanded to the right. It could be that the circle contains the emitter doping that has entered the base area due to a weakness in the manufacturing process.

In the lower area on the left side there is another disturbance, which is only noticeable by a relatively bright dot. This is probably a minor irregularity as seen in the BUX22 built by ST Microelectronics (https://www.richis-lab.de/Bipolar07.htm#defect (https://www.richis-lab.de/Bipolar07.htm#defect)).


(https://www.richis-lab.de/images/transistoren/a98x13.jpg)

The prolonged operation in the base emitter breakdown ultimately destroyed the junction in the lower left corner.

In detail, you can see that the surface on the edge of the outer metallisation has also been etched in the form of the MESA structure.


(https://www.richis-lab.de/images/transistoren/a98x14.jpg)

The path along which the current has concentrated after the junction has collapsed is clearly visible. Both on the side of the base and on the side of the emitter, a path can be seen that leads to the junction. The metal layer has melted on both sides and cracks can be seen in the surface between them.

Due to the damage, the contact area in the passivation layer is now also more clearly visible. Inside the recess, the silicon has melted a little. Presumably it has entered into an alloy with the metal layer. Where the passivation layer begins, the current path appears greenish. Following this, the current path narrows and the current density increases. According to the optical appearance, the material is more damaged in this area. The emitter area seems to be less damaged, perhaps because of the higher doping.


https://www.richis-lab.de/2N3055_17.htm (https://www.richis-lab.de/2N3055_17.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 04, 2023, 08:46:49 pm
I hope you weren't using a bench supply (CC/CV with big capacitor on the output) for that test...were you?  :horse:

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 04, 2023, 08:55:12 pm
I hope you weren't using a bench supply (CC/CV with big capacitor on the output) for that test...were you?  :horse:

Tim

 ;D
That wasn´t the problem. The problem was to much heat. I try to take the pictures without a bulky heatsink. Most of the time that works quite well but sometimes I´m too impatient and even a few watt generate a lot of heat...  >:D
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 04, 2023, 10:10:05 pm
I know, for the initial failure it's just straight up heat; I mean the subsequent melting. >:D

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 05, 2023, 03:30:00 am
I assume concentrating the power at such a small area would melt the structures independent of the bench supply.
...but yes, it was the cheap one...  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2023, 12:54:25 pm
(https://www.richis-lab.de/images/transistoren/a99x01.jpg)

The BUX37 is a Darlington transistor with an integrated free-wheeling diode. The present model was produced by Thomson Semiconducteurs in 1980. The transistor blocks up to 400V and conducts up to 15A. If the case temperature remains below 100°C, up to 35W can be dissipated. The current gain is at least 20.


(https://www.richis-lab.de/images/transistoren/a99x02.jpg)

(https://www.richis-lab.de/images/transistoren/a99x03.jpg)

In the package there is a large heatspreader. Channels in the heatspreader allow excess solder to flow off.


(https://www.richis-lab.de/images/transistoren/a99x04.jpg)

The dimensions of the die are 6,0mm x 5,5mm. A transparent varnish protects the transistor against environmental influences. The particles on the protective varnish were created while opening the case.


(https://www.richis-lab.de/images/transistoren/a99x08.jpg)

(https://www.richis-lab.de/images/transistoren/a99x09.jpg)

It is obviously a MESA transistor. From the outside to the inside, parts of the surface have turned brown.


(https://www.richis-lab.de/images/transistoren/a99x05.jpg)

(https://www.richis-lab.de/images/transistoren/a99x06.jpg)

The protective coating can be removed relatively easily, allowing an unobstructed view of the structures.


(https://www.richis-lab.de/images/transistoren/a99x07.jpg)

The driver transistor is located in the right area (yellow), the transistor of the power path is integrated in the left area (red). The free-wheeling diode and the resistors are not visible here. A more detailed description of the structure and operation of such a Darlington transistor can be found within the documentation of the SU111 (https://www.richis-lab.de/Bipolar59.htm (https://www.richis-lab.de/Bipolar59.htm)).


(https://www.richis-lab.de/images/transistoren/a99x11.jpg)

(https://www.richis-lab.de/images/transistoren/a99x10.jpg)

Under the thick protective coating, there is obviously an additional thin passivation layer on the transistor. Either the coating itself has turned brown or there is contamination underneath. Brown degradation of the silicon seems rather unlikely.

The outer edges of the transistor are very rough. It could be that the surface has been scored for singulation. In the valley of the MESA structure an additional step can be seen.


(https://www.richis-lab.de/images/transistoren/a99x12.jpg)

Some spots give the impression that the degradation has penetrated into the area of the semiconductor and not only has changed the protective layer. However, it could be that the passivation has changed especially at edges and that is why it looks like this.


https://www.richis-lab.de/BipolarA34.htm (https://www.richis-lab.de/BipolarA34.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 13, 2023, 03:01:50 pm
I wonder how they implemented the diode. P-region buried under the emitter contact, perhaps?  There's a faint outline under the emitter metal, but that could just be connections.

I wonder if a parasitic SCR (PNPN) breakdown mode could be activated, say with large dV/dt, or forward or reverse avalanche...

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2023, 03:19:09 pm
I wonder how they implemented the diode. P-region buried under the emitter contact, perhaps?  There's a faint outline under the emitter metal, but that could just be connections.

I assume that's the same as with the SU111:
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3585647/#msg3585647 (https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3585647/#msg3585647)


I wonder if a parasitic SCR (PNPN) breakdown mode could be activated, say with large dV/dt, or forward or reverse avalanche...

I don't see an SCR but with that much p and n you can never be sure.
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on July 13, 2023, 03:24:36 pm
Ah, right, they could use the base layer; which also implements the B-E resistor, assuming the resistivity and geometry of the layer works out (which seems to be the case). Nice. :)

Any PNPN behavior would be driven by lateral motion, which is probably a very long shot over the width of this die, yeah.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on July 13, 2023, 03:35:32 pm
These integrated Darlingtons are really a piece of art. A simpel looking piece of art but nevertheless a piece of art.  8)
Title: Re: Transistors - die pictures
Post by: Noopy on August 04, 2023, 03:56:51 am
(https://www.richis-lab.de/images/transistoren/b01x02.jpg)

(https://www.richis-lab.de/images/transistoren/b01x01.jpg)

The Intersil CA3096 is a transistor array with three NPN and two PNP transistors. The maximum collector-emitter voltage is at least 45/40V (NPN/PNP). Collector currents up to 50/10mA are specified. The current gain at a collector current of 1mA is in the range of 150-500 / 20-200.

The variant with the index A is an assortment with more closely specified characteristics. Less precisely specified variants carry the index C. The present component, without an index at this point, represents the basic variant. The second letter, here an E, stands for the housing variant.


(https://www.richis-lab.de/images/transistoren/b01x03.jpg)

The marking makes a somewhat unclean impression. However, as we will soon see, it is in fact a CA3096.


(https://www.richis-lab.de/images/transistoren/b01x06.jpg)

The datasheet contains a picture of the metal layer showing the arrangement of the transistors and the dimensions.


(https://www.richis-lab.de/images/transistoren/b01x05.jpg)

(https://www.richis-lab.de/images/transistoren/b01x04.jpg)

The edge length of the die is 0,99mm. 6270 is most likely the internal project designation. In the lower right area there is a structure with a cross that makes it possible to check the alignment of the masks against each other.

The NPN and PNP transistors show the familiar structure. Since PNP transistors in an NPN process are less efficient, they had to be made much larger. Each PNP transistor consists of seven individual elements. This is the only way to achieve reasonably similar specifications.

The datasheet contains typical offset values for the case that one sets up a differential amplifier with the Q1/Q2 or Q4/Q5 transistors. The offset voltage of the PNP version is somewhat lower than that of the NPN version. The significantly larger areas of the PNP transistors ensure that the real base-emitter voltages that occur are closer to the typical value. With the smaller NPN transistors, the scattering of the doping has a greater effect.


https://www.richis-lab.de/BipolarA35.htm (https://www.richis-lab.de/BipolarA35.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 07, 2023, 04:24:23 am
(https://www.richis-lab.de/images/transistoren/b02x01.jpg)

The LMG3410 from Texas Instruments is a transistor based on gallium nitride (GaN). Like silicon carbide, the semiconductor material gallium nitride has a large bandgap and is therefore very well suited to switching high voltages and high currents quickly and with low losses. Compared to SiC, the maximum permissible reverse voltage of GaN transistors is usually somewhat lower, but GaN transistors can be switched faster. In addition to a GaN power transistor, the LM3410 contains a driver and a silicon MOSFET, so that control is relatively straightforward.

Up to 480V can be applied to the LMG3410 continuously. The absolute maximum ratings specify 600V and even 800V transiently. The 800V pulses may only occur one million times. Edge steepnesses of up to 150V/ns are permissible. At a junction temperature of 125°C, 12A is specified as the maximum current flow. At 25°C, the Absolute Maximum Ratings specify up to 40A. Pulses applied for less than 100ns may rise to 100A. The resistance in the active state is given as 70mΩ/110mΩ (25°C/125°C).

The output capacitance of the GaN transistor is 71pF. However, the absence of a body diode is particularly interesting, which is why the reverse recovery charge can be specified as 0nC. This means that in the application in a half- or H-bridge, the reverse charge is much less critical. Although a GaN FET does not have an intrinsic diode like a silicon MOSFET, operation in the third quadrant, i.e. current flow from source to drain, is still possible.


(https://www.richis-lab.de/images/transistoren/b02x10.jpg)

The above image is from an application report by Texas Instruments ("Does GaN Have a Body Diode? - Understanding the Third Quadrant Operation of GaN"). It shows how a GaN transistor can be constructed. A GaN transistor is a so-called HEMT, a High Electron Mobility Transistor. In it, one area contains a so-called two-dimensional electron gas ("2DEG"), in which electrons can flow with very little resistance.

On Wikipedia you can read that it is a special form of the MESFET, i.e. a J-FET in which the channel is not constricted by an inverse doping but by a metal contact. In the meantime, however, there are also variants with an insulated gate electrode. The sectional view shown here appears to contain such an insulating layer. The extension of the source and gate lead controls the electric field in the active area, resulting in a higher dielectric strength.


(https://www.richis-lab.de/images/transistoren/b02x11.jpg)

Texas Instruments also explains in the above document why GaN transistors behave as if they contain a body diode. If Vgs is above Vth, current can flow through the device in both directions (blue). If Vgs is below Vth (red), the transistor blocks positive Drain-Source voltages. If Vds is negative, however, the transistor becomes conductive again. The negative drain potential leads to a positive Gate-Drain voltage, which has the same effect in the third quadrant as a positive Vgs in the first quadrant. However, the characteristic curve is shifted by Vgs-Vth and the channel resistance is slightly higher.

Compared to a MOSFET with a body diode, the voltage drop across a GaN transistor in the third quadrant is relatively high. The LMG3410 datasheet specifies 7,8V at a current flow of 10A. This results in correspondingly high losses. Either the current-time area should be kept small in this quadrant or the transistor should be switched on.


(https://www.richis-lab.de/images/transistoren/b02x02.jpg)

(https://www.richis-lab.de/images/transistoren/b02x03.jpg)

The transistor is in a VQFN package with an exposed pad. The datasheet shows the pinning of the LMG3410. The upper contacts all carry the drain potential. The lower area has a similar number of contacts for the source potential. In addition, there are pins for the supply and the control of the transistor.


(https://www.richis-lab.de/images/transistoren/b02x04.jpg)

The datasheet contains a block diagram showing how the LMG3410 works. As with SiC transistors, the first GaN FETs were exclusively normally on. Here, such a normally on GaN FET is used. If you still want intrinsically safe behaviour, you can build a cascode, as in the case of the UnitedSiC UF3C120040K4S (https://www.richis-lab.de/FET05.htm (https://www.richis-lab.de/FET05.htm)). In the case of the LMG3410, a more complex approach has been taken. There is a normal Si MOSFET in series with the GaN transistor. Here, however, the two transistors do not form a cascode circuit, but are controlled independently of each other.

The LMG3410 requires a supply voltage between 9,5V and 18V. From this, a linear regulator generates a 5V supply for the controller. A switching regulator also generates a negative supply of -13,9V to safely switch off the GaN transistor. The current consumption is typically 43mA.

A push-pull stage either connects the gate of the GaN transistor to the source potential, thus making it conductive, or it connects the gate to the negative supply, thus switching it off. A resistor on pin RDRV allows the switching speed to be varied between 30V/ns and 100V/ns. The LMG3410 contains both an overcurrent and an overtemperature monitor that protects the device against overload.

If the LMG3410 is in the idle state (current consumption 80µA) or is not supplied, the Si MOSFET is switched off and the gate of the GaN transistor is connected to the source terminal of the device. In this state, the voltage across the Si MOSFET rises until the gate of the GaN transistor becomes so negative that it also blocks and thus carries most of the blocking voltage. In the meantime, it is possible to produce normally off GaN FETs too, which simplifies safe application.


(https://www.richis-lab.de/images/transistoren/b02x05.jpg)

There are two dies in the package. The upper die is the GaN transistor (5,8mm x 2,1mm). The lower die is the control circuit, which also contains the Si MOSFET (5,2mm x 1,3mm). The control circuit detached from the carrier when the package was opened. It was later reinserted into the picture.


(https://www.richis-lab.de/images/transistoren/b02x06.jpg)

The bondwires can be reconstructed quite easily. GaN transistors usually conduct the current laterally. Here, the Si MOSFET is also constructed laterally. This is possible quite efficiently because the Si MOSFET must be able to carry the full current of the LMG3410 (40A), but no high blocking voltage rating is necessary. Probably a little more than 20V should be sufficient.


(https://www.richis-lab.de/images/transistoren/b02x07.jpg)

(https://www.richis-lab.de/images/transistoren/b02x08.jpg)

Half of the area of the control circuit is taken up by the Si MOSFET. The other half contains the supply circuits, the control and the drivers.


(https://www.richis-lab.de/images/transistoren/b02x09.jpg)

The die is 0,25mm thick and carries a very solid metal layer with a height of about 11µm.


(https://www.richis-lab.de/images/transistoren/b02x15.jpg)

(https://www.richis-lab.de/images/transistoren/b02x12.jpg)

The structures of the control system are too small and too complex to be analysed in detail. However, some function blocks can be identified on the basis of the massive lines. The linear regulator of the 5V voltage regulator can be recognised by its contacting, as can the highside and the lowside transistor of the buck-boost converter (pink).

The gate contact of the GaN FET is connected to the source potential of the component via a very large transistor (blue). Another, not quite as large transistor connects the gate to the negative supply potential (green). The source potential is connected to the die via two paths. A whole row of bondwires leads to the Si MOSFET. Three more bondwires connect the control circuit to the source potential of the device. This keeps interference from the power path away from the control circuit.


(https://www.richis-lab.de/images/transistoren/b02x13.jpg)

(https://www.richis-lab.de/images/transistoren/b02x14.jpg)

The design obviously dates from 2015 and the designation LMG3410A1 can be found on the die. A1 could stand for a first revision.

The LMG3410 switches off in case of an overcurrent event and remains switched off. The LMG3411 is listed in the same datasheet. However, in the event of an overcurrent this device switches off just for the current cycle. Most likely, the LMG3411 uses the same controller, which is simply configured differently in production.


(https://www.richis-lab.de/images/transistoren/b02x16.jpg)

In this picture the GaN transistor is rotated 180° compared to the pictures above. It has a whole row of drain and source bondpads. On the left and right, you can contact the gate potential via three bondpads each, whereby only the left contacts are used in the LMG3410.


(https://www.richis-lab.de/images/transistoren/b02x17.jpg)

On the right edge, in addition to some designations, the masks are shown too.


(https://www.richis-lab.de/images/transistoren/b02x18.jpg)

The drain potential is flanked by the source potential over the entire circumference. Regular undercrossings of the wide source lines lead the gate potential into the active area.


(https://www.richis-lab.de/images/transistoren/b02x19.jpg)

The structures can be easily identified by looking at the structure published by Texas Instruments. Thin vertical lines form the contacts of the source (blue) and drain (red) to the active area. The source metal line is wider. Underneath is the gate electrode.


https://www.richis-lab.de/FET33.htm (https://www.richis-lab.de/FET33.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on August 07, 2023, 05:30:23 am
Thanks for the pics.  :-+
As TI wrote on it, it is now clear this AINT E4.  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on August 16, 2023, 08:03:17 pm
(https://www.richis-lab.de/images/transistoren/b03x01.jpg)

The RCA 2N3670 is a thyristor designed for use in 240V power supplies. A peak voltage of 400V is permissible on a permanent basis. For short periods, the reverse voltage may rise to 660V. An effective value of 12,5A and a peak value of 200A are specified for the current flow.

In addition to the 2N3670, the data sheet lists the three similar variants 2N3668, 2N3669 and 2N4103 with different blocking voltages (100V, 200V, 600V).


(https://www.richis-lab.de/images/transistoren/b03x02.jpg)

(https://www.richis-lab.de/images/transistoren/b03x03.jpg)

(https://www.richis-lab.de/images/transistoren/b03x04.jpg)

The electrical contacting is similar to that of germanium power transistors. The cathode potential is supplied from the left. The gate potential is transferred by a metal strip from the right to the centre of the assembly. Here, however, the semiconductor rests almost directly on the bottom of the housing and there is a metal ring above it. It could be that the ring not only bridges the distance between the semiconductor and the contact plate, but is also necessary to distribute the current evenly over the semiconductor.


(https://www.richis-lab.de/images/transistoren/b03x07.jpg)

(https://www.richis-lab.de/images/transistoren/b03x08.jpg)

Inside the metal ring, you can see the semiconductor itself between the gate contact in the middle and the outer cathode contact.


(https://www.richis-lab.de/images/transistoren/b03x05.jpg)

(https://www.richis-lab.de/images/transistoren/b03x06.jpg)

The protective lacquer obscures the view of the active area. You still can see the approximately 0,15mm thick semiconductor disc. There is a layer of solder above and below it. In the bottom of the base plate there is a flat socket.


https://www.richis-lab.de/BipolarA36.htm (https://www.richis-lab.de/BipolarA36.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on August 18, 2023, 04:02:22 am
(https://www.richis-lab.de/images/transistoren/b04x01.jpg)

(https://www.richis-lab.de/images/transistoren/b04x02.jpg)

The KF517 is a PNP small signal transistor built by Tesla. Vceo is 30V. The collector current may be up to 500mA. The datasheet specifies a cut-off frequency of at least 50MHz. Without additional cooling, a power dissipation of 0,8W can be dissipated, with ideal cooling, 2,6W is possible. FX stands for production in May 1974. Although there is no index here, the KF517 have been sorted by their amplification factor: A offers a gain factor between 35 and 120, B guarantees 90 - 300 and C is specified with 60 - 160.


(https://www.richis-lab.de/images/transistoren/b04x03.jpg)

(https://www.richis-lab.de/images/transistoren/b04x04.jpg)

(https://www.richis-lab.de/images/transistoren/b04x05.jpg)

The edge length of the die is 1,0mm. The bondwires are welded to the metal layer in two places. The structures do not show any special features. The emitter surface appears brown. Around the emitter, the dark green base area can be seen, which is also located below the emitter. Below this, in turn, extends the collector area, which is recognisable around the base area in a somewhat lighter green. In the outer area are the usual simple auxiliary structures.


(https://www.richis-lab.de/images/transistoren/b04x06.jpg)

(https://www.richis-lab.de/images/transistoren/b04x07.jpg)

(https://www.richis-lab.de/images/transistoren/b04x08.jpg)

(https://www.richis-lab.de/images/transistoren/b04x09.jpg)

The base-emitter junction breaks down at 15V. If the transistor is operated with limited current in this area, the familiar glowing appears. At 10mA, the glow is still sporadic but already very uniform. From 20mA over 50mA, the glow spreads until at 100mA the junction on the surface lights up completely.  8)


https://www.richis-lab.de/BipolarA37.htm (https://www.richis-lab.de/BipolarA37.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: konohimawm on August 18, 2023, 11:02:32 am
I like Tesla KF517 so clean    :-+
Title: Re: Transistors - die pictures
Post by: TurboTom on August 19, 2023, 12:27:34 am
The wrinkled bond wires made me laugh... But I guess that's just a collateral of cutting the case open. Very well done, Noopy, I really enjoy your contributions! Thanks so much for this  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on August 19, 2023, 03:08:19 am
It is a pleasure!  8)  I still have pretty much to do.  :-/O

Actually i didn´t touch the bondwires. They are like they were before.  ;D
Title: Re: Transistors - die pictures
Post by: Noopy on August 24, 2023, 07:26:47 pm
(https://www.richis-lab.de/images/transistoren/b05x01.jpg)

Here we have another BUX22. This BUX22 from ST Microelectronics seems to be newer than the refurbished BUX22 from 1988, whose initial marking still has an old format (https://www.richis-lab.de/Bipolar07.htm (https://www.richis-lab.de/Bipolar07.htm)). At the same time, it is older than the BUX22 with the perforated emitter (https://www.richis-lab.de/Bipolar08.htm (https://www.richis-lab.de/Bipolar08.htm)), since it still has the relatively thick, structured base plate.


(https://www.richis-lab.de/images/transistoren/b05x02.jpg)

(https://www.richis-lab.de/images/transistoren/b05x03.jpg)

(https://www.richis-lab.de/images/transistoren/b05x04.jpg)

As with the other BUX22, two dies were used here. The bondwires are not as unusually thick as in the refurbished BUX22 from 1988, but the emitters were contacted with two bondwires each.


(https://www.richis-lab.de/images/transistoren/b05x05.jpg)

It is a challenge to route the four emitter bondwires without collision in the limited volume and to connect them to the corresponding pin. In order to be able to weld all the wires at all, they have been lined up at the side of the connection pin.


(https://www.richis-lab.de/images/transistoren/b05x08.jpg)

(https://www.richis-lab.de/images/transistoren/b05x09.jpg)

In contrast to the newer BUX22 with the perforated emitter, classic transistor structures were used in this BUX22.


(https://www.richis-lab.de/images/transistoren/b05x06.jpg)

The BUX22 seen here does not contain an additional heatspreader due to the massive baseplate of the package. As with the refurbished BUX22 from 1988, however, there are metal plates under the dies. The different thermal expansion coefficients of the silicon and the base plate create mechanical stresses. The metal plates can absorb these tensions or equalize the different thermal expansion coefficients.


(https://www.richis-lab.de/images/transistoren/b05x07.jpg)

The transistors do not show any unusual structures, even in detail.


(https://www.richis-lab.de/images/transistoren/b05x10.jpg)

(https://www.richis-lab.de/images/transistoren/b05x11.jpg)

(https://www.richis-lab.de/images/transistoren/b05x12.jpg)

(https://www.richis-lab.de/images/transistoren/b05x13.jpg)

As with the other BUX22, the base-emitter junction breaks down relatively late. Here the breakdown voltage is -15V. The current rises from 10mA to 100mA to 500mA to 1A.

The glow speaks for a relativ even current distribution between the two transistors. On the die, the glow occurs first and intensified to the left of the emitter contact area.


https://www.richis-lab.de/BipolarA38.htm (https://www.richis-lab.de/BipolarA38.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: floobydust on August 24, 2023, 07:58:53 pm
BUX22 rated 250V 40A 350W hFE 20-60, fT 10MHz "silicon multiepitaxial planar NPN".
Title: Re: Transistors - die pictures
Post by: Noopy on August 24, 2023, 08:05:00 pm
BUX22 rated 250V 40A 350W hFE 20-60, fT 10MHz "silicon multiepitaxial planar NPN".

Peak current 50A (10ms).
Title: Re: Transistors - die pictures
Post by: Noopy on August 30, 2023, 04:06:24 am
(https://www.richis-lab.de/images/transistoren/b06x01.jpg)

The BD115 is an early silicon transistor that can block up to 180V. The development goes back to Valvo. Today, there are also models from younger manufacturers such as CDIL. This transistor has no logo and no manufacturer's name, but it seems to be very old, which indicates that it was made by Valvo.

The specified reverse voltage shows that it is still an early process. While the collector-base breakdown voltage is 245V, the collector-emitter breakdown voltage is specified with just 180V. At this voltage, the collector-base leakage current already increases so much that the transistor is overloaded. The datasheet gives a value of 0,55mA for a reverse voltage of 200V and a junction temperature of 200°C. At this operating point, 110mW are generated in the transistor.

The collector current may be up to 150mA. At a case temperature of 100°C, the TO-39 case can dissipate up to 6W. The DC gain is specified as 60 (100V/50mA). The cut-off frequency is 145MHz.


(https://www.richis-lab.de/images/transistoren/b06x02.jpg)

(https://www.richis-lab.de/images/transistoren/b06x03.jpg)

The actual transistor is located on a pedestal in the housing.


(https://www.richis-lab.de/images/transistoren/b06x04.jpg)

(https://www.richis-lab.de/images/transistoren/b06x05.jpg)

The edge length of the die is 0,75mm. It bears the typical structures of a power transistor. Base and emitter contacts mesh in a comb shape. The rounded corners of the base and collector area have a positive effect on the electric field, which improves the insulation capability. The distance between base and collector potential is relatively large.

An interesting artefact can be found at the upper right edge. The base metal layer is slightly discoloured at this point, the collector frame seems to have melted towards the base surface. Either there was a relatively low-energy flashover that did not damage the remaining structures or it was a weakness in the manufacturing of the transistor.


https://www.richis-lab.de/BipolarA39.htm (https://www.richis-lab.de/BipolarA39.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: exe on August 30, 2023, 08:37:14 am
The collector current may be up to 150mA. At a case temperature of 100°C, the TO-39 case can dissipate up to 6W. The DC gain is specified as 60 (100V/50mA). The cut-off frequency is 145MHz.

That's not bad specs at all! Though I'm a bit skeptical about 6W dissipation.
Title: Re: Transistors - die pictures
Post by: Noopy on August 30, 2023, 09:21:47 am
I agree with you, the 6W are questionable...  ???
Title: Re: Transistors - die pictures
Post by: SeanB on August 30, 2023, 10:39:01 am
6W if you can just keep that base plate of the can at 25C, which is probably only possible when you have soldered it to a nice beryllium oxide washer, which in turn is on a nice Kovar heat spreader, cooled with Freon. Those TO39 cans normally had a finned heatsink, so can do 1W to 2W, depending on airflow, though I have seen them with clamp on heat spreaders that interfaced using a beryllia insulator to allow you to attach to a heatsink. Mil spec units, so price was not something they worried about, but they really wanted that TO39 package, but did not want to go full hybrid on it. We had some that had been reverse engineered, and those hybrids that came out were really nice, but the price per each was high.
Title: Re: Transistors - die pictures
Post by: Noopy on September 17, 2023, 03:35:09 am
(https://www.richis-lab.de/images/transistoren/b07x01.jpg)

The Philips BRY39 is described in the associated datasheet as a Programmable Unijunction Transistor and a Silicon Controlled Switch. It is a so-called thyristor tetrode. The properties of a thyristor tetrode are described in more detail in the context of the 3N84 (https://www.richis-lab.de/BipolarA40.htm (https://www.richis-lab.de/BipolarA40.htm)). The BRY39 blocks up to 70V and conducts up to 175mA, briefly 2.5A, non-repetitively up to 3A.


(https://www.richis-lab.de/images/transistoren/b07x02.jpg)

The datasheet of the BRY39 shows the typical structure of a thyristor tetrode. It is a thyristor structure in which, in contrast to a thyristor or a programmable unijunction transistor, all four layers are contacted. However, a thyristor tetrode can of course be used as a thyristor or programmable unijunction transistor.


(https://www.richis-lab.de/images/transistoren/b07x03.jpg)

(https://www.richis-lab.de/images/transistoren/b07x04.jpg)

(https://www.richis-lab.de/images/transistoren/b07x05.jpg)

The dimensions of the die are 0,43mm x 0,42mm. There are auxiliary structures in the right-hand corners that make it possible to monitor the alignment of the masks. To the right of the innermost contact, you think you can see some damage. However, it seems to be just an artefact of the bond process and some dirt.


https://www.richis-lab.de/BipolarA40.htm (https://www.richis-lab.de/BipolarA40.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 27, 2023, 06:29:44 pm
(https://www.richis-lab.de/images/transistoren/b08x01.jpg)

The 2N2894 is a PNP transistor from National Semiconductor optimized for fast switching in the saturation region. Here you can see the bin with the index A, which is still a bit faster than the 2N2894. The A variant offers a cutoff frequency of at least 800MHz. The maximum turn-off time of 25ns is also worth mentioning. The blocking voltage is 12V. The current gain is typically 120 (150 for the 2N2894). The collector current must not exceed 200mA.


(https://www.richis-lab.de/images/transistoren/b08x07.jpg)

In the Discrete Databook from National Semiconductor there is a note that the 2N2984 is based on process 64. This is a process with a gold doping. Only transistors from process 65 (among others 2N4208) are faster, but with a maximum collector current of 50mA they are much less powerful.


(https://www.richis-lab.de/images/transistoren/b08x06.jpg)

If a bipolar transistor is operated in saturation, it contains very many free charge carriers. With an interruption of the base current, the number of free charge carriers is reduced continuously, but relatively slowly. As long as free charge carriers are still present, a collector current continues to flow. If you want to switch off bipolar transistors coming from the saturation region and you want to do it fast, you have to take additional measures to discharge free charge carriers. In the simplest case, the base and emitter are connected with a resistor through which the free charge carriers can exit the transistor. Such resistors are often found in Darlington transistors. Alternatively, the bipolar transistor can be driven with a push-pull stage to actively discharge the free charge carriers. In some cases it may be advantageous not to operate the transistor in saturation.

While manufacturing a transistor, one can optimize its intrinsic turn-off time by introducing gold doping. The gold atoms act as recombination points, which reduces the average lifetime of the free charge carriers. The IEEE article "Parasitic Effects in Microelectronic Circuits" deals with this technique. In this paper the influence of gold doping on parasitic effects is mainly considered, but the tables you can see here also show how the basic specifications are improved.

Process C contains gold doping and can be compared with process B, which has no gold doping. Process A lacks a buried collector. The lower table shows the reverse recovery times of the transistor junctions. The times are significantly shorter with gold doping. As a side effect, the leakage current into the substrate is also reduced, which is documented in the upper table. Due to the shorter lifetime, fewer free charge carriers reach the substrate.


(https://www.richis-lab.de/images/transistoren/b08x02.jpg)

(https://www.richis-lab.de/images/transistoren/b08x03.jpg)

(https://www.richis-lab.de/images/transistoren/b08x04.jpg)

It turns out that the structures on the die correspond to the illustration in National Semiconductor's Discrete Databook.


(https://www.richis-lab.de/images/transistoren/b08x05.jpg)

The transistor contains two emitter areas. The geometries could be interpreted as follows: The green area in the center contains the n-doping, which represents the base region. Within it are the two heavily p-doped emitter areas, which are hidden under the metal layer. The orange-red area represents the p-doped collector area, which is connected with low impedance to the substrate and to the package via a stronger, violet p-doping.


https://www.richis-lab.de/BipolarA41.htm (https://www.richis-lab.de/BipolarA41.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on October 30, 2023, 05:06:00 pm
(https://www.richis-lab.de/images/transistoren/b09x01.jpg)

The Siemens BSY34 is a fast switching transistor that was used to drive magnetic bubble memory. The dielectric strength is specified as 50V. The maximum collector current is 600mA. Besides a cutoff frequency of 400MHz, switching times of 30ns and 50ns respectively can be expected (tone/off). The BSY34 datasheet additionally lists the BSY58, which seems to be a slightly worse bin.


(https://www.richis-lab.de/images/transistoren/b09x02.jpg)

(https://www.richis-lab.de/images/transistoren/b09x03.jpg)

The die of the transistor is placed rotated by 45° between the pins of base and emitter. Neither the ball-wedge nor the wedge-wedge technique was used for the electrical connection. On the die, the bonding wires apparently already had the appropriate length before the bonding process. The wire was then welded to the metal surfaces on both sides. On the pins, the wire was processed in a similar way, but welded twice. It seems like the wires were cut off over the edges of the pins.


(https://www.richis-lab.de/images/transistoren/b09x04.jpg)

(https://www.richis-lab.de/images/transistoren/b09x05.jpg)

The edge length of the die is 0,60mm. The emitter surface describes the shape of a U. The fanned out base contact surrounds the emitter area and thus ensures a low-resistance connection to the active base area. In the lower right corner there are auxiliary structures which allow to evaluate the alignment of the masks against each other.


(https://www.richis-lab.de/images/transistoren/b09x06.jpg)

(https://www.richis-lab.de/images/transistoren/b09x07.jpg)

(https://www.richis-lab.de/images/transistoren/b09x08.jpg)

(https://www.richis-lab.de/images/transistoren/b09x09.jpg)

It can be assumed that heavily doped silicon was used in the BSY34 to achieve the high switching speeds. The low emitter base blocking voltage fits to this, which the datasheet specifies with 5V.

Here, the breakdown of the emitter base junction occurs at -6V and the well-known glow of the avalanche breakdown occurs. With increasing current, individual breakdown points change to a uniform glow over the whole junction. The current flow is 10mA, 20mA, 30mA and 50mA.


(https://www.richis-lab.de/images/transistoren/b09x10.jpg)

As described in detail in the context of the SF137 (https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)), the recombination of charge carriers can be observed in normal operation with the help of infrared imaging. The glow allows just a subjective comparison, yet it appears to be much more limited in the BSY34 than in the SF137. In the SF137, without collector current, the light extends far beyond the base contact.

With increasing collector current, the geometry of the glow appearance changes just slightly in the BSY34. However, there seems to be a slight shift towards the emitter, which would fit the shift of the recombination center of grarvity.

The optimization towards fast switching times could be an explanation for the more concentrated glow. If the free charge carriers are more concentrated in the active area, they probably can be discharged faster.


https://www.richis-lab.de/BipolarA42.htm (https://www.richis-lab.de/BipolarA42.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on October 30, 2023, 07:42:56 pm
Hmm, not so much heavily doped, given the modest breakdown voltages; gold doping likely though?

Could well be higher doping in the connection layers (by extension, substrate -- being the collector connecting layer -- if epitaxial type), forcing recombination near the junctions and reducing switching resistance.

(...Ah yes, "double diffused epitaxial", so that could be.  That is, n+ substrate; n- epitaxy for collector drift region; p (base) then n+ (emitter) diffusions; and, maybe p+ base contact diffusion?, but would that be triple, or can it be done at the same time as emitter?  Not sure.  ...Nah, don't think there's a base contact layer. That checks out then.)

Also I guess an extra "emitter" ring around everything, for guard ring?  I... forget exactly how those work, but that looks like what they've done anyway.

Tim
Title: Re: Transistors - die pictures
Post by: Wolfgang on October 30, 2023, 07:48:35 pm
Unglaublich saubere Fertigung. für das Alter. Haben wir Restströme von dem Ding ?
In English, sorry: Very clean manufacturing, indeed. Do we have leakage currents for this part ?
Title: Re: Transistors - die pictures
Post by: Noopy on October 30, 2023, 09:11:42 pm
Hmm, not so much heavily doped, given the modest breakdown voltages; gold doping likely though?

A modest Vce but the Veb is quite low with 5V. Nevertheless, of course there are HF transistors with higher doping concentration.
Gold doping is at least possible but you don´t find a hint in the datasheet.


Could well be higher doping in the connection layers (by extension, substrate -- being the collector connecting layer -- if epitaxial type), forcing recombination near the junctions and reducing switching resistance.

(...Ah yes, "double diffused epitaxial", so that could be.  That is, n+ substrate; n- epitaxy for collector drift region; p (base) then n+ (emitter) diffusions; and, maybe p+ base contact diffusion?, but would that be triple, or can it be done at the same time as emitter?  Not sure.  ...Nah, don't think there's a base contact layer. That checks out then.)

I agree with your explanation.


Also I guess an extra "emitter" ring around everything, for guard ring?  I... forget exactly how those work, but that looks like what they've done anyway.

Since the "emitter ring" is in the collector area it generates no real junction. But probably it hat a positive effect...


Unglaublich saubere Fertigung. für das Alter. Haben wir Restströme von dem Ding ?

Hello Wolfgang! Some german words?  ;)
The cutoff current is at room temperature <70nA (Vcbo=50V).
Really a nice transistor.  8)
Title: Re: Transistors - die pictures
Post by: Wolfgang on October 30, 2023, 11:07:16 pm
I see a datasheet leakage of 70nA maximum, but I am sure its in the picoamps when measured. Any measurements available ?
Title: Re: Transistors - die pictures
Post by: Noopy on October 31, 2023, 12:09:19 pm
DMM6500 says 30nA @40V.
But I had to take the open part because I have just this one. It is now open for some days, let´s say one or two weeks.
I tried to keep the transistor away from light.
Title: Re: Transistors - die pictures
Post by: Wolfgang on October 31, 2023, 10:43:55 pm
Thanks, I will try to get some parts that are still in their can. Opening normally kills leakage current due to moisture and other gases.
Where did you get your parts from ?
Title: Re: Transistors - die pictures
Post by: Noopy on November 01, 2023, 03:54:38 am
Thanks, I will try to get some parts that are still in their can. Opening normally kills leakage current due to moisture and other gases.
Where did you get your parts from ?

I agree with you.

Unfortunately my contact doesn´t sell any more:
https://www.ebay.de/itm/386171199806 (https://www.ebay.de/itm/386171199806)
 :(
Title: Re: Transistors - die pictures
Post by: Wolfgang on November 01, 2023, 11:38:52 am
Dont worry, it was me who bought the rest  ^-^
Title: Re: Transistors - die pictures
Post by: Noopy on November 02, 2023, 02:15:56 pm
(https://www.richis-lab.de/images/transistoren/b10x01.jpg)

(https://www.richis-lab.de/images/transistoren/b10x02.jpg)

The SSY20 built by the Halbleiterwerk Frankfurt Oder was developed as an alternative to the BSY34 for use in magnetic bubble memory. The specifications are accordingly similar. The SSY20 blocks 40V and conducts up to 600mA. The switching times of 50ns and 100ns (tone/off) respectively are somewhat longer than those of the BSY34. PL stand for a production in December 1971.


(https://www.richis-lab.de/images/transistoren/b10x03.jpg)

(https://www.richis-lab.de/images/transistoren/b10x04.jpg)

(https://www.richis-lab.de/images/transistoren/b10x05.jpg)

The edge length of the die is 0,7mm. On the surface there are some major scratches. The active structures remind of the structure of power transistors. In the lower left corner there is a geometry that allows to check the alignment of the masks.


(https://www.richis-lab.de/images/transistoren/b10x06.jpg)

(https://www.richis-lab.de/images/transistoren/b10x07.jpg)

(https://www.richis-lab.de/images/transistoren/b10x08.jpg)

(https://www.richis-lab.de/images/transistoren/b10x09.jpg)

(https://www.richis-lab.de/images/transistoren/b10x10.jpg)

(https://www.richis-lab.de/images/transistoren/b10x11.jpg)

The breakdown of the base-emitter junction occurs at -9,4V. In the images seen here, the current increases from 10mA to 50mA in 10mA steps. The luminescent effect appears uneven, suggesting that the structures are somewhat inhomogeneously built or contain imperfections.


(https://www.richis-lab.de/images/transistoren/b10x12.jpg)

The recombination of free charge carriers emits light in the infrared range, which makes it possible to visualize the recombination centers. We had that before. However, the distribution of the light islands and their luminances are not particularly informative for the SSY20.


(https://www.richis-lab.de/images/transistoren/b11x01.jpg)

(https://www.richis-lab.de/images/transistoren/b11x02.jpg)

Here you can see another SSY20 transistor, also produced in December 1971.


(https://www.richis-lab.de/images/transistoren/b11x03.jpg)

(https://www.richis-lab.de/images/transistoren/b11x04.jpg)

(https://www.richis-lab.de/images/transistoren/b11x05.jpg)

The design and structures are basically the same. However, there is significant damage in the lower area of the transistor. The visual appearance of the defect and its location suggest that it is not caused by an electrical overload but was more likely a weakness in the production.


(https://www.richis-lab.de/images/transistoren/b12x01.jpg)

This transistor is not labeled, but it is known that it is also an SSY20.


(https://www.richis-lab.de/images/transistoren/b12x02.jpg)

(https://www.richis-lab.de/images/transistoren/b12x03.jpg)

(https://www.richis-lab.de/images/transistoren/b12x04.jpg)

The design is similar to the design of the already documented SSY20 transistors. Here, the first bond process at the emitter was obviously not successful.


(https://www.richis-lab.de/images/transistoren/b13x01.jpg)

Here you can see the structure of another unlabeled SSY20 transistor.


(https://www.richis-lab.de/images/transistoren/b13x02.jpg)

(https://www.richis-lab.de/images/transistoren/b13x03.jpg)

The bond quality in this transistor is also not ideal. At the base potential (left) the area next to the bondwire is severely damaged. According to the optical appearance, a bond process took place there, during which the bondwire came loose again. In the lower right area of the transistor, the metal layer is heavily scratched, which could also have happened during the bond process.


(https://www.richis-lab.de/images/transistoren/b13x04.jpg)

(https://www.richis-lab.de/images/transistoren/b13x05.jpg)

(https://www.richis-lab.de/images/transistoren/b13x06.jpg)

(https://www.richis-lab.de/images/transistoren/b13x07.jpg)

(https://www.richis-lab.de/images/transistoren/b13x08.jpg)

The breakdown of the base-emitter path occurs earlier in this model, at -6,5V. The currents here are 10mA, 20mA, 50mA, 100mA and 200mA. Despite the damage, the light distribution is still relatively even.


(https://www.richis-lab.de/images/transistoren/b13x09.jpg)

The collector-base junction can also be driven in avalanche at 77,5V. The current flow in this picture is just 10mA. However, that´s already a power dissipation of 7,8W, which is why this operating point can only be reached for a very short time.

As with the base-emitter breakdown, a light effect occurs with the collector-base breakdown too. The documentation of the 2N2857 (https://www.richis-lab.de/Bipolar16.htm (https://www.richis-lab.de/Bipolar16.htm)) has shown how clear this effect can be. In the SSY20, only a small point lights up in the right area of the lower edge.


https://www.richis-lab.de/BipolarA43.htm (https://www.richis-lab.de/BipolarA43.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on November 02, 2023, 09:48:42 pm
Sheesh, feels like a couple of those were bonding practice! :-DD

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on November 03, 2023, 11:04:22 am
Yeah, they definitely had some problems getting the bonds robust.  :palm:

I had one minor mistake:
The BSY34 and the SSY20 were designed for ferrite core memory, not for magnetic bubble memory.
Title: Re: Transistors - die pictures
Post by: Noopy on November 05, 2023, 08:06:29 pm
(https://www.richis-lab.de/images/transistoren/b14x01.jpg)

The 2N2646 is a unijunction transistor. In contrast to the so-called programmable unijunction transistors such as the 2N6027 (https://www.richis-lab.de/Bipolar14.htm (https://www.richis-lab.de/Bipolar14.htm)), the 2N2646 is a real unijunction transistor, i.e. it contains just one junction. A manufacturer cannot be determined. The numbers 0248 could be a date code. The component would therefore have been manufactured in 2002.


(https://www.richis-lab.de/images/transistoren/b14x07.jpg)

The pictures above are taken from the book "Beyond the Transistor: 133 Electronics Projects" and show, among other things, the structure of a unijunction transistor. It consists of an n-doped elongated element. The ends of this element are labelled base1 and base2. A p-type doping is inserted and contacted at the side. This connection is called the emitter. The n-doped element represents two resistors, between which a diode is formed at the emitter connection. If a voltage is applied between the two base connections, a certain potential is established at the emitter depending on the position of the p-doping.

The characteristic curve is shown in simplified form. It shows the voltage Ve between the emitter and the lower base as a function of the emitter current. The behaviour is easier to understand if Ve is varied and the resulting current is observed. As long as the potential applied to the emitter from the outside is lower than the potential set by the voltage divider between base 1 and base 2, the pn junction is isolating the emitter. Just a very small leakage current (1-2) flows into the emitter. If the pn junction becomes conductive, more current can flow into the emitter. At first glance, the behaviour of the voltage Ve is unusual, as it decreases in this area as the current increases (2-3).

There is only n-doped material between the base contacts. The current flow in the first part of the characteristic curve can therefore only take place via free electrons. As soon as current flows into the emitter, additional positive charge carriers ("holes") flow from the p-doped area into the unijunction transistor. The additional transport mechanism reduces the resistance between the base contacts.

The unijunction transistor can therefore represent a negative resistance. This feature was used in the past to build oscillators with little component effort. Another advantage was certainly that the structures are less complicated than those of a transistor and were therefore probably easier to manufacture.


(https://www.richis-lab.de/images/transistoren/b14x06.jpg)

In February 1968 (Volume 41), the journal Electronics describes the development of the design. The first unijunction transistors consisted of an n-doped cuboid into which the emitter contact and thus a p-doping was alloyed at the same time. This principle was further improved until the unijunction transistors could be manufactured using planar technology and finally integrated with other circuit components.


(https://www.richis-lab.de/images/transistoren/b14x02.jpg)

This 2N2646 contains a modern-looking die. What is unusual is that the bond connections on the pins have been additionally protected with a type of varnish.


(https://www.richis-lab.de/images/transistoren/b14x04.jpg)

(https://www.richis-lab.de/images/transistoren/b14x03.jpg)

The edge length of the die is 0,45 mm. A manufacturer cannot be determined here either. Just the Cyrillic letters КБB (KBV) in the top right-hand corner provide a clue. For the simple design of a unijunction transistor, the structures on the die are surprisingly complex.


(https://www.richis-lab.de/images/transistoren/b14x05.jpg)

It is certain that the emitter is contacted from the left and the base1 from the right. The potential of base 2 is tapped via the housing, i.e. via the substrate. The reddish area under the emitter contact must contain a p-type doping. It appears that three possible emitters have been integrated here. There must be a strong n-doping under the smaller central base contact, which ensures a low-resistance connection of the n-doped area. On closer inspection, you can see that the three possible emitters have different distances to the base 1 contact. If the emitter bondwire is placed differently, the properties of the component can be modified.

The contact in the bottom left-hand corner appears to be relatively deep. It is most likely a connection to the substrate and therefore to base2. Thin lines lead to the emitter areas. Probably the lines makes it possible to connect unused emitter areas to the base2 potential. The low base2 potential guarantees that no charge carriers flow from the inactive emitter surfaces into the active area.


https://www.richis-lab.de/BipolarA44.htm (https://www.richis-lab.de/BipolarA44.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 11, 2023, 08:03:13 pm
(https://www.richis-lab.de/images/transistoren/b15x01.jpg)

(https://www.richis-lab.de/images/transistoren/b15x02.jpg)

The BC109 is a low-noise transistor from the first generation of the BCxxx family. The maximum collector emitter voltage is 25V. Collector currents of up to 200mA are permissible. The cut-off frequency is specified at more than 100MHz. The amplification factor of the transistors lies between 200 and 800, with index B limiting the range to 200-450. The manufacturer of this transistor cannot be identified.


(https://www.richis-lab.de/images/transistoren/b15x03.jpg)

(https://www.richis-lab.de/images/transistoren/b15x04.jpg)

(https://www.richis-lab.de/images/transistoren/b15x05.jpg)

The dimensions of the die are 0,40mm x 0,39mm. The base contact only covers half of the emitter area.


https://www.richis-lab.de/BipolarA45.htm (https://www.richis-lab.de/BipolarA45.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 20, 2023, 03:49:59 am
(https://www.richis-lab.de/images/transistoren/b16x01.jpg)

(https://www.richis-lab.de/images/transistoren/b16x02.jpg)

The КT117 is a unijunction transistor, as described in more detail in the 2N2646. The logo belongs to the Russian Ulyanovsk radio tube plant and had to be rotated 90° anti-clockwise on the small housing. The index, here a B (Latin V), shows which resistance can be expected between the two base connections. There are a total of four bins with two different resistance values and two different factors by which the resistance value can change.


(https://www.richis-lab.de/images/transistoren/b16x03.jpg)

(https://www.richis-lab.de/images/transistoren/b16x04.jpg)

(https://www.richis-lab.de/images/transistoren/b16x05.jpg)

The housing contains a die with an edge length of 1,13 mm. A transparent potting protects the semiconductor.


(https://www.richis-lab.de/images/transistoren/b16x06.jpg)

This is the classic structure of a unijunction transistor, as documented in the 2N2646. The bottom of the n-doped substrate represents the base contact B1. The right-hand bondpad forms the second base contact. The left-hand bondwire transmits the emitter potential.

At first glance, one might have thought that the right-hand area was the p-doped emitter. This is obviously not the case here. No edge can be recognised around the emitter bondpad. It can therefore be assumed that the entire area around the bondpad B2 contains a p-type doping. Two frame structures can be recognised under and next to the base bondpad. Low-resistance contacting of an n-doped surface requires a local strong n-doping. The inside of the two edges shows the area that contains this stronger n-doping. The outer edge is a window within the emitter surface and exposes the n-doped substrate. The outer frame most likely contains an n-doping and thus represents a clean termination of the emitter surface.


https://www.richis-lab.de/BipolarA46.htm (https://www.richis-lab.de/BipolarA46.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on November 23, 2023, 08:24:38 pm
(https://www.richis-lab.de/images/transistoren/b17x01.jpg)

The PNP germanium transistor AF201 built by Siemens is a high-frequency transistor with a cut-off frequency of at least 100 MHz. The blocking voltage is 25V. The maximum permissible collector current is 10mA. The AF201 can dissipate up to 225mW. The junction temperature must not exceed 90°C.

The AF200 is also described on the same datasheet. The AF200 and the AF201 are obviously two grades of the same transistor type. The guaranteed current amplification of the AF201 is slightly lower than that of the AF200 at a factor of 20 and the feedback capacitance is slightly higher (maximum 0,7pF).


(https://www.richis-lab.de/images/transistoren/b17x02.jpg)

The housing contains a white compound that protects the structures from environmental conditions and improves heat dissipation towards the housing.


(https://www.richis-lab.de/images/transistoren/b17x05.jpg)

(https://www.richis-lab.de/images/transistoren/b17x04.jpg)

(https://www.richis-lab.de/images/transistoren/b17x03.jpg)

The AF201 has four pins. In addition to the collector, base and emitter, one pin contacts the housing exclusively. The transistor is located on a carrier insulated from the housing, which is welded to the collector pin.


(https://www.richis-lab.de/images/transistoren/b17x06.jpg)

(https://www.richis-lab.de/images/transistoren/b17x07.jpg)

(https://www.richis-lab.de/images/transistoren/b17x08.jpg)

A kind of protective lacquer is applied to the die. Due to the varying thickness of the lacquer, the interferences in the layer create a repeating rainbow pattern. The edge length of the die is 0,5mm. The structure of this type of high-frequency transistor is described in more detail in the 2N1561 (https://www.richis-lab.de/BipolarA47.htm (https://www.richis-lab.de/BipolarA47.htm)). The area around the active area has been etched down so that just a pedestal with an edge length of 0,1 mm remains. This measure reduces the parasitic capacitances. The base is diffused into the pedestal. On top of the pedestal is a base contact and the emitter, both alloyed into the base.


https://www.richis-lab.de/BipolarA47.htm (https://www.richis-lab.de/BipolarA47.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2023, 04:57:42 am
(https://www.richis-lab.de/images/transistoren/b18x01.jpg)

Here you can see the germanium power transistor OC864A, which was developed in the Funkwerk Erfurt but never went into series production. Only a few sample exist in the Thuringian Museum of Electrical Engineering (https://www.elektromuseum.de (https://www.elektromuseum.de)). The following background information also comes from this museum.

In 1959, the VEB Funkwerk Erfurt (FWE) ceased production of transmitter tubes. The capacities freed up were used to start developing germanium power transistors in the so-called Zentrallabor für Empfängerröhren (ZLE). An important basis for this work was a Soviet documentation. In addition to the necessary dimensions of the germanium crystal, it described how to etch the material, which alloy materials to use and which geometries to aim for. Alloying was carried out in a graphite mould under vacuum. The design of the alloying furnace was also taken from the Soviet documentation. However, the optimum temperatures and times for the alloying process were missing and had to be determined from tests. At the end of 1962, after the development had been completed, the results were transferred to the Halbleiterwerk Frankfurt Oder (HFO).


(https://www.richis-lab.de/images/transistoren/b18x02.jpg)

The transistor housing is made of copper. The base plate is 3 mm thick.


(https://www.richis-lab.de/images/transistoren/b18x03.jpg)

Letters are stamped into the base plate to identify the pins for the base and emitter. The indentation creates a socket on the top, on which the actual transistor is located.


(https://www.richis-lab.de/images/transistoren/b18x04.jpg)

(https://www.richis-lab.de/images/transistoren/b18x05.jpg)

(https://www.richis-lab.de/images/transistoren/b18x06.jpg)

The construction and connection technology is not unusual for a germanium power transistor. A ring-shaped electrode contacts the germanium platelet and thus transmits the base current. The emitter current is supplied in the centre.


(https://www.richis-lab.de/images/transistoren/b18x07.jpg)

The quality of the solder connection between the base pin and the contact plate is very poor.


(https://www.richis-lab.de/images/transistoren/b18x08.jpg)

The germanium crystal has an edge length of 5,6mm. An edge length of 6mm should enable a power dissipation of 25W. An edge length of 4mm was intended for 15W transistors.


(https://www.richis-lab.de/images/transistoren/b18x09.jpg)

To produce the emitter shown here, an indium-gallium mixture was alloyed into the germanium. Pure indium was used at the collector. It is easy to recognise that there are two metal layers on the germanium platelet. The lower element is the alloy material that forms the emitter. The emitter contact was soldered onto this with a solder that melts at a low temperature.


(https://www.richis-lab.de/images/transistoren/b18x10.jpg)

(https://www.richis-lab.de/images/transistoren/b18x11.jpg)

The germanium disc was manufactured at the Halbleiterwerk Stahnsdorf, which belonged to VEB Halbleiterwerk Frankfurt Oder (HFO). The surface shows the familiar structure resulting from the etching process used to clean the surface. The edges appear to have been reworked in some way. The surface structure changes in these areas.


(https://www.richis-lab.de/images/transistoren/b18x14.jpg)

The germanium disc is approximately 0,12 mm thick. There is a 0,05mm thick solder layer and the 0,10mm thick base electrode.


(https://www.richis-lab.de/images/transistoren/b18x12.jpg)

(https://www.richis-lab.de/images/transistoren/b18x13.jpg)

The transistor does not lie completely flat on the socket of the base plate. This allows a better view of the collector area. The alloy material, which covers a larger area on the collector than on the emitter, is clearly visible. Very little solder appears to have been used for the collector connection. With such a small contact area, it is difficult to dissipate the transistor's power loss. In order to obtain high-quality transistors, this process would definitely need some optimization.


(https://www.richis-lab.de/images/transistoren/b18x15.jpg)

On closer inspection, you can see that so-called whiskers that have formed on the base. This is usually tin, which forms such crystal structures over time under certain circumstances. These whiskers can cause short circuits.


(https://www.richis-lab.de/images/transistoren/b18x16.jpg)

(https://www.richis-lab.de/images/transistoren/b18x17.jpg)

(https://www.richis-lab.de/images/transistoren/b18x18.jpg)

The diameter of the whiskers is just 5µm. There appears to be a complete connection between collector and base.

Some of the images also show small dendrites, as were found much more extensively in GD241 (https://www.richis-lab.de/BipolarA12.htm (https://www.richis-lab.de/BipolarA12.htm)).


(https://www.richis-lab.de/images/transistoren/b18x19.jpg)

The overview image shows the proportions once again. It could be that the whisker had caused a short circuit, which then was melted by a current flow. This would explain the thickening at the end of the whisker.


https://www.richis-lab.de/BipolarA48.htm (https://www.richis-lab.de/BipolarA48.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2023, 05:26:57 am
By the way: In the background that are 1250 pictures, which occupy 60GB on my network storage...  ;D
Title: Re: Transistors - die pictures
Post by: pickle9000 on December 06, 2023, 05:34:18 am
Awesome!
Title: Re: Transistors - die pictures
Post by: RoGeorge on December 06, 2023, 12:04:11 pm
Interesting story, beautiful pics, thanks!  :-+

Just out of curiosity, estimating R of a tin whisker:
R = \$\rho\$*L/S
\$\rho_{\mathrm{Sn}}\$ = 10.9E-8\$\Omega\$*m
L = 0.1mm
d = 5um

R = 10.9E-8 * 0.1E-3 / (3.14 * 25E-12 / 4) = 1.09/(3.14*1.25) = roughly 1/4 = 0.25\$\Omega\$  ???

I was expecting a much bigger R from such a thin wire.
Title: Re: Transistors - die pictures
Post by: MegaVolt on December 06, 2023, 12:08:01 pm
I was expecting a much bigger R from such a thin wire.
It burns very easily turning into plasma. But the plasma channel has low resistance.
Title: Re: Transistors - die pictures
Post by: mawyatt on December 06, 2023, 02:05:13 pm
Nice images and storyline Noopy :clap:

Thanks for the continual efforts in showing these great semiconductor images, along with the excellent storylines & analysis :-+

Best,
Title: Re: Transistors - die pictures
Post by: AnalogTodd on December 06, 2023, 02:08:31 pm
Interesting story, beautiful pics, thanks!  :-+

Just out of curiosity, estimating R of a tin whisker:
R = \$\rho\$*L/S
\$\rho_{\mathrm{Sn}}\$ = 10.9E-8\$\Omega\$*m
L = 0.1mm
d = 5um

R = 10.9E-8 * 0.1E-3 / (3.14 * 25E-12 / 4) = 1.09/(3.14*1.25) = roughly 1/4 = 0.25\$\Omega\$  ???

I was expecting a much bigger R from such a thin wire.
When you're talking short distances, resistances turn out to be fairly low value. A gold bond wire that is 1mil diameter ends up at about 4.5 milliohm. What is the big deal on it isn't so much the resistance, but instead the fusing current. That's dependent on a number of variables from mass/cross sectional area to power dissipation and time. Sitting in open air like those will also lower the fusing current (over-molded bond wires can handle higher currents).
Title: Re: Transistors - die pictures
Post by: Noopy on December 06, 2023, 05:28:49 pm
Thank you all for your input and positiv feedback!  :)

I had a small mistake in the name: It was called OC846A not OC864A.  :-+
Title: Re: Transistors - die pictures
Post by: floobydust on December 06, 2023, 10:39:53 pm

Here you can see the germanium power transistor OC864A, which was developed in the Funkwerk Erfurt but never went into series production. Only a few sample exist in the Thuringian Museum of Electrical Engineering (https://www.elektromuseum.de (https://www.elektromuseum.de)). The following background information also comes from this museum.

In 1959, the VEB Funkwerk Erfurt (FWE) ceased production of transmitter tubes. The capacities freed up were used to start developing germanium power transistors in the so-called Zentrallabor für Empfängerröhren (ZLE). An important basis for this work was a Soviet documentation. In addition to the necessary dimensions of the germanium crystal, it described how to etch the material, which alloy materials to use and which geometries to aim for. Alloying was carried out in a graphite mould under vacuum. The design of the alloying furnace was also taken from the Soviet documentation. However, the optimum temperatures and times for the alloying process were missing and had to be determined from tests. At the end of 1962, after the development had been completed, the results were transferred to the Halbleiterwerk Frankfurt Oder (HFO). [...]

"An important basis for this work was a Soviet documentation. "

High purity germanium crystal growing tech was a big deal back then. I'm curious who really had it or was it simply stolen IP?
Bell Labs 1953 William Pfann (https://en.wikipedia.org/wiki/William_Gardner_Pfann) developed "zone refining" and I saw Japan using it to make transistors in the early 1950's.
Title: Re: Transistors - die pictures
Post by: Noopy on December 07, 2023, 12:25:42 pm
"An important basis for this work was a Soviet documentation. "

High purity germanium crystal growing tech was a big deal back then. I'm curious who really had it or was it simply stolen IP?
Bell Labs 1953 William Pfann (https://en.wikipedia.org/wiki/William_Gardner_Pfann) developed "zone refining" and I saw Japan using it to make transistors in the early 1950's.


Well I don´t know. Would definitely be interesting...
Title: Re: Transistors - die pictures
Post by: Noopy on January 26, 2024, 04:20:39 am
(https://www.richis-lab.de/images/transistoren/b19x01.jpg)

This Siemens 2N3055 has two character sequences that could be a date code: 5E and S8. According to DIN EN 60062, the E would stand for the year 1974, S would refer to the year 1984. The Siemens 2N3055H from 1983 (https://www.richis-lab.de/2N3055_14.htm (https://www.richis-lab.de/2N3055_14.htm)) is already printed with the modern four digit date code. This indicates that the 2N3055 shown here was manufactured in May 1974.


(https://www.richis-lab.de/images/transistoren/b19x02.jpg)

As in the Siemens 2N3055 from 1975 (https://www.richis-lab.de/2N3055_01.htm (https://www.richis-lab.de/2N3055_01.htm)), there is a white powder in the package, which presumably is a drying agent.


(https://www.richis-lab.de/images/transistoren/b19x03.jpg)

(https://www.richis-lab.de/images/transistoren/b19x04.jpg)

The die is located on a base, which can also be seen on the back of the housing. The connection between the pins and the die is made with ordinary wires, not with bondwires. The wires are soldered on both sides.


(https://www.richis-lab.de/images/transistoren/b19x05.jpg)

The die shows the typical irregular surface of a hometaxial transistor. The wires were soldered directly to the metal layer.


(https://www.richis-lab.de/images/transistoren/b19x07.jpg)

The die is coated with a kind of protective varnish that peels off in some places.


(https://www.richis-lab.de/images/transistoren/b19x06.jpg)

A piece of the metal layer is missing at one point. There you can see what the openings in the passivation layer look like, through which the semiconductor is contacted.


(https://www.richis-lab.de/images/transistoren/b19x08.jpg)

(https://www.richis-lab.de/images/transistoren/b19x09.jpg)

(https://www.richis-lab.de/images/transistoren/b19x10.jpg)

The base-emitter junction only breaks down at -50V. High values are typical for hometaxial transistors. However, such high values have so far only occurred with 2N3055 transistors from Siemens.

A large part of the current flows in the upper range of the die (50mA, 100mA, 200mA).


https://www.richis-lab.de/2N3055_18.htm (https://www.richis-lab.de/2N3055_18.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: RoGeorge on January 26, 2024, 08:27:17 am
As in the Siemens 2N3055 from 1975 (https://www.richis-lab.de/2N3055_01.htm (https://www.richis-lab.de/2N3055_01.htm)), there is a white powder in the package, which presumably is a drying agent.

When we were kids, we were never discarding broken power transistors.  We were keeping them for their thermal paste inside.  They were easy to open by squeezing the cap a little, in a vice.  Smaller transistors were also having some thermal paste inside (e.g. the Ge type AC180/AC181), but way little than a TO-3 capsule.  The thermal paste was matte white, and slightly less thick than toothpaste, about the same as the white thermal paste available now for CPU radiators.  Though, I'm not sure is any of those power transistors I've opened were 2N3055.  Maybe they were Ge power transistors.  :-//

Could that white powder be, in fact, thermal paste solidified with time?
Title: Re: Transistors - die pictures
Post by: Noopy on January 26, 2024, 02:53:15 pm
I know that there is often thermal paste in smaller packages. Up to now I just have seen it in Ge transistors:

(https://www.richis-lab.de/images/howto/01x05.jpg)

It makes sense to enhance the power dissipation from the die to the housing.

In TO3 packages I have never seen thermal paste. Just this one had a strange potting:

(https://www.richis-lab.de/images/Transistoren/68x02.jpg)

I´m not sure if thermal paste makes sense in a TO3 package. The thermal resistance through the base plate is quite low. I don´t think thermal paste would enchance that very much. On the other hand the upper part of the TO3 has a very high thermal resistance compared to the base plate and the heatsink. I don´t think you can dissipate a lot more thermal power if you enhance this path.
Are you sure you found the thermal paste in TO3 transistors?

On the other hand corrosion was quite a problem, so a drying agent absolutely makes sense. Often we saw something like a pill.
Title: Re: Transistors - die pictures
Post by: iMo on January 26, 2024, 04:24:50 pm
Are you sure you found the thermal paste in TO3 transistors?
It is not a thermal paste.. It is an expressionistic vision of the late twentieth's century technology progress ("Controlled Currents in a Pot")..
Title: Re: Transistors - die pictures
Post by: SeanB on January 26, 2024, 06:10:38 pm
GE transistors in TO3 and TO66 packages had the thermal paste, simply because the junction is lifted off the actual die attach, and the low temperature limit for Ge means any improved contact is desperately needed. Thus the compound, while a silicon planar transistor could get away with just having a soldered connection, and a drying agent to keep it dry and oxygen free, with the large silicon area providing enough thermal transfer, plus the max junction temperature of 150C as opposed to 70C helps a lot.

Got some genuine Newmarket transistors, courtesy of Sir Clive, in an unused and old amplifier kit, the infamous ones that were rather notorious because they were made from all reject transistors from the scrap test pile at Newmarket, bought by the ton by Sinclair, and binned into dead, sort of dead, sort of working and works good enough, at least at 15V. Might dig them up, though there are some Ge transistors in older packaging I also have around, OC36, unmarked as to manufacturer or date. Might have to open one and see what is inside.
Title: Re: Transistors - die pictures
Post by: RoGeorge on January 26, 2024, 07:18:47 pm
Are you sure you found the thermal paste in TO3 transistors?

It was very long time ago, maybe not TO-3, but certainly the same kind of capsule with a thick diamond shaped metal plate, like TO-3 use to have.  Could have been Ge power transistors, can't say for sure.  We were kids in the 5th grade or so, maybe it was some other goo inside, and we believed it to be thermal paste just like in the AC180/181K.  :-//
Title: Re: Transistors - die pictures
Post by: SeanB on January 26, 2024, 07:51:35 pm
Well, took one and not so gently asked it to open up. Inside a clear sticky gel fill, not white, but still both a heat transfer compound and a protective blob. Rather interesting smell on opening, a faint smell that is similar to old oil, and showing the nice clean copper of the mounting and the copper top. Interesting is the wires in the package are made of a ferrous alloy, tinned outside.
Title: Re: Transistors - die pictures
Post by: Noopy on January 26, 2024, 08:03:35 pm
It seems I have to open some more transistors!  ;D
Title: Re: Transistors - die pictures
Post by: Zoli on January 27, 2024, 08:19:47 am
I vaguely recall seeing white silicone heat compound in ASZ15(Tunsgram); but that was around '79...
Title: Re: Transistors - die pictures
Post by: Noopy on February 01, 2024, 07:41:16 pm
(https://www.richis-lab.de/images/transistoren/b20x01.jpg)

The darlington transistor shown here was marked by Motorola with an application-specific label. The transistor came from a power supply of a CDC magnetic disk station. It was obviously manufactured in 1978.


(https://www.richis-lab.de/images/transistoren/b20x11.jpg)

The schematic of the power supply shows that it is a Darlington transistor.


(https://www.richis-lab.de/images/transistoren/b20x02.jpg)

(https://www.richis-lab.de/images/transistoren/b20x03.jpg)

The die is located on a round heatspreader and is protected by a transparent potting. The design is similar to the Motorola MJ3001 from 1979 (https://www.richis-lab.de/Bipolar60.htm (https://www.richis-lab.de/Bipolar60.htm)), but the die is significantly smaller.


(https://www.richis-lab.de/images/transistoren/b20x04.jpg)

There is a dark line on the side of the heatspreader. The color appears unusual. Perhaps it is the remains of a flux which was applied before the die was soldered onto the heatspreader.


(https://www.richis-lab.de/images/transistoren/b20x05.jpg)

The potting is transparent, but distorts the view of the structures.


(https://www.richis-lab.de/images/transistoren/b20x06.jpg)

The potting can be removed very easily with the help of a silicone remover. In the bottom left corner, however, the potting adheres surprisingly strongly. Perhaps the material in this area has changed. The transistor had failed, so high temperatures may well have occurred locally.

The structures are typical of a medium-power Darlington transistor. The driver transistor is isolated to some extent in the top right-hand corner. In contrast to a normal transistor, the emitter contact is arranged in a U-shape around the base contact. From this emitter, the metal layer leads to the base area of the power transistor, which takes up the rest of the die. There, the base contact runs around the emitter as usual.

The size and design differ significantly from the Motorola MJ3001. This could be due to a different blocking voltage. The MJ3001 is specified with a blocking voltage of 80V. The transistor shown here only has to generate a 5V power supply from a 9V power supply.


(https://www.richis-lab.de/images/transistoren/b20x10.jpg)

(https://www.richis-lab.de/images/transistoren/b20x07.jpg)

The outer edges are etched down to create the familiar MESA structure, which ensures a clean base-collector interface. An edge can be seen on the surface of the MESA structure. This could be the passivation layer that protects the active areas of the transistor.


(https://www.richis-lab.de/images/transistoren/b20x08.jpg)

The driver transistor is surrounded by insulation trenches created with the MESA structure. The geometry extends the line between the driver and power transistor. As described in MJ3001, the base-emitter resistor of the driver transistor is located underneath this metal line.


(https://www.richis-lab.de/images/transistoren/b20x09.jpg)

The metallization of the power transistor is damaged in one corner. According to the visual impression, this is a manufacturing error and not a damage caused by an overload.


https://www.richis-lab.de/BipolarA49.htm (https://www.richis-lab.de/BipolarA49.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 04, 2024, 07:47:42 am
(https://www.richis-lab.de/images/transistoren/b21x01.jpg)

With the AT-32011, Hewlett Packard had a fast bipolar transistor in its portfolio. The AT-32011 is optimized for applications with low supply voltages in the frequency ranges 900MHz, 1,8GHz or 2,4GHz. According to the datasheet, the transistor is based on a self-aligned transistor process with a cut-off frequency of 10GHz. The maximum reverse voltage is 11V. The collector current must not exceed 32mA. In order to achieve a high cut-off frequency, a very high doping was selected, which is reflected in the low base-emitter breakdown voltage of -1,5V.


(https://www.richis-lab.de/images/transistoren/b21x02.jpg)

(https://www.richis-lab.de/images/transistoren/b21x03.jpg)

The edge length of the die is only 230µm. The labeling shows that Hewlett Packard developed the design in 1994. 320 appears to be the designation of the basic project, from which at least two bins emerge. In addition to the AT-32011, the datasheet also lists an AT-32033. The AT-32011 offers a slightly higher amplification factor than the AT-32033. The emitter connection is marked with an E, which is covered here by remnants of the bondwire.

The transistor structures themselves are too small to be resolved. They are located under the dark strip in the center, which is approximately 70µm x 15µm in size. The datasheet reveals that there are 20 emitters with a pitch of 3,2µm. The base connections are located between the emitter connections and both must maintain a certain distance from each other. This means that a resolution of less than 1µm is required in order to be able to image the structures to some extent. The comb-shaped contacts can just be guessed.


https://www.richis-lab.de/BipolarA50.htm (https://www.richis-lab.de/BipolarA50.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 12, 2024, 05:10:20 am
(https://www.richis-lab.de/images/transistoren/b22x07.jpg)

The Philips BLX15 is a RF power transistor in a SOT-55/3 package. In North America, it was distributed by Amperex, which belonged to Philips. The advertisement above is from Electronic Design 18 magazine from September 1973 and shows which transistors are optimised for which power and frequency classes. The BLX15 is the most powerful transistor in the 30 MHz frequency range.

The blocking voltage of the BLX15 is specified as 53V. The large gap to the maximum collector-base voltage is striking, it is specified as 110V. The datasheet allows a continuous collector current of 6,5A and a peak current of 20A. The cut-off frequency is 275MHz. The housing can continuously dissipate up to 195W power loss.


(https://www.richis-lab.de/images/transistoren/b22x01.jpg)

The BLX15 has four large contacts. The collector contact has a rectangular opening and is labelled with a C on the package. The emitter potential is led out to the right and left. The base potential is applied to the lower contact.


(https://www.richis-lab.de/images/transistoren/b22x02.jpg)

The transistor can be screwed into a heatsink with a thread. The thread merges into a thick metal plate. The upper part of the housing consists of two plastic elements, between which the connections are led out.


(https://www.richis-lab.de/images/transistoren/b22x03.jpg)

The upper plastic element can be broken off. Underneath is a metal cover that is glued to the package. This bond protects the semiconductor from the environment. The plastic housing itself is obviously not sufficiently sealed.


(https://www.richis-lab.de/images/transistoren/b22x04.jpg)

The cover can be removed from the housing with a knife. The transistor was declared defective. The damage is already obvious here. The left side of the cover and the corresponding area in the housing are heavily blackened. But there is also clear damage on the right-hand side.


(https://www.richis-lab.de/images/transistoren/b22x05.jpg)

With a little more magnification, the structure of the BLX15 becomes clearly recognisable.


(https://www.richis-lab.de/images/transistoren/b22x06.jpg)

From below, the collector potential is fed to the transistors and led through the substrate into their active area. A metal bracket connects the emitter potentials supplied from the left and right. Four bondwires are available per transistor for the emitter current. The base current, which arrives from above, is even transmitted with five bondwires each.

The transistors are located on a ceramic carrier. This means that the BLX15 can be screwed into a heat sink without additional insulation. However, the ceramic slightly impairs heat conduction. It is remarkable that the datasheet nevertheless specifies a continuous power dissipation of 195W.


(https://www.richis-lab.de/images/transistoren/b22x08.jpg)

The bondwires on the emitter side of the left die have completely melted. An arc must have been burning for some time, as the edge of the metal rail also was melted considerably.


(https://www.richis-lab.de/images/transistoren/b22x10.jpg)

The insulation area of the ceramic is blackened over a large area. Metal has accumulated in front of the die. As the bondwires do not have that much volume, it must be material from the emitter bud bar.


(https://www.richis-lab.de/images/transistoren/b22x11.jpg)

The energy input into the die was so high that the silicon broke in several areas. Nevertheless, the structure of the transistor can still be recognised. There are eight columns, each of which is grouped into pairs. The base current is supplied from one side of each column and the emitter current is dissipated on the other side.


(https://www.richis-lab.de/images/transistoren/b22x12.jpg)

Obviously, there were high equalising currents between the gaps. The metal layer is completely destroyed in the upper area where it connected the gaps.


(https://www.richis-lab.de/images/transistoren/b22x21.jpg)

Each of the eight columns contains 52 rows, each with four emitter contacts. It appears to be an overlay transistor, as described in more detail in the 2N3553 (https://www.richis-lab.de/Bipolar22.htm (https://www.richis-lab.de/Bipolar22.htm)). On the right, all rows are connected to a common resistor strip, which then leads to the emitter potential. The resistor strip ensures symmetrical current distribution across the rows.


(https://www.richis-lab.de/images/transistoren/b22x09.jpg)

The right-hand side of the BLX15 is less badly damaged. All four bondwires are melted but still recognisable. The die is partially melted and discoloured in the area where the bondwires were attached, but the area around the transistor is still intact.


(https://www.richis-lab.de/images/transistoren/b22x13.jpg)

Here, too, all the connecting elements on the upper edge have been destroyed.


(https://www.richis-lab.de/images/transistoren/b22x14.jpg)

Where the bondwires made contact with the emitter potential, the metal layer melted over a large area.


(https://www.richis-lab.de/images/transistoren/b22x15.jpg)

Here you can see a second defective BLX15. The package and labelling corresponded to the BLX15 above. The metal cover of this transistor was thermally opened.


(https://www.richis-lab.de/images/transistoren/b22x16.jpg)

(https://www.richis-lab.de/images/transistoren/b22x17.jpg)

Here, too, both transistors are destroyed. The degree of destruction is slightly less severe. The emitter bondwires of both transistors are completely melted.


(https://www.richis-lab.de/images/transistoren/b22x18.jpg)

(https://www.richis-lab.de/images/transistoren/b22x19.jpg)

The transistors are constructed in exactly the same way as in the first BLX15. Here, the connections between the emitter areas are still intact.


(https://www.richis-lab.de/images/transistoren/b22x20.jpg)

There is an artefact on the right-hand transistor slightly away from the bondwires that could be the starting point of the destruction. The emitter resistor between two emitter lines appears to have been destroyed locally, regardless of the surroundings. The collector line for the emitter current and some of the emitter lines have also melted in this area. Of course with such massive destruction, it is not possible to say for sure whether this was really the starting point of the failure.


https://www.richis-lab.de/BipolarA51.htm (https://www.richis-lab.de/BipolarA51.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 15, 2024, 07:02:45 pm
(https://www.richis-lab.de/images/transistoren/b23x01.jpg)

Just a small transistor...
The BC178 is a PNP transistor that is the complementary type to the BC108. A manufacturer cannot be determined. 7244 could be a date code. The year of production would therefore be 1972, which seems plausible. The maximum collector emitter voltage is 25V. The current carrying capacity is 100mA continuous, 200mA maximum. The variant with the index A is specified with a current amplification of typically 180 (125-260). The cut-off frequency is 150MHz.


(https://www.richis-lab.de/images/transistoren/b23x02.jpg)

(https://www.richis-lab.de/images/transistoren/b23x03.jpg)

(https://www.richis-lab.de/images/transistoren/b23x04.jpg)

The structure of the transistor shows no special features. The edge length of the die is 0,34 mm. The silicon is broken at the lower edge.


https://www.richis-lab.de/BipolarA52.htm (https://www.richis-lab.de/BipolarA52.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on February 15, 2024, 08:31:26 pm
I talked to a guy who is very familiar with markings. He said this is probably a Valvo transistor.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on February 24, 2024, 08:58:31 pm
Do you remember I once showed you some IRF3708? I now have some more and I have a different opinion if they are a genuine part or fake.

I won´t post all the pictures here because I´m to lazy.  ;D

Here we have a list of all the IRF3708: https://www.richis-lab.de/Transistoren_FET_IRF3708.htm (https://www.richis-lab.de/Transistoren_FET_IRF3708.htm)


#1 to #3 are the old MOSFETs. Back then I thought that all of them are fake parts but since I found some IRF3708 with the same die as the #1 I assume this one is genuine.

#4a and #4b are interesting fake parts from AliExpress with two different transistors relabeled.

#5 and #6 look somehow strange as #1 but they all have the same die and came from different suppliers: Reichelt 2022, Reichelt 2013, Völkner 2022.

#7 finally looks like the datasheet describes the package. It was bought 2022 from ELV. The die is the same as in #1, #5 and #6 so approving that these are originals.


 :-/O
Title: Re: Transistors - die pictures
Post by: T3sl4co1l on February 24, 2024, 11:50:54 pm
I've suspected that they gave up on the HEXFET pattern a long time ago; it's possible they went with stripe (as basically? everyone else has) since, perhaps just the first generation or three even?  The name might then remain as the internal name for the chain of development, or as an IP scheme (trademark and related patents?).  All 2nd-source / substitute parts call theirs "planar stripe" or something to that effect, which I wonder if it was (at first?) a patent-evasion strategy, or just more suitable to their existing processes, or in fact the better way and everyone's converged on it now.  Well, the latter seems likely, heh.

Tim
Title: Re: Transistors - die pictures
Post by: Noopy on February 25, 2024, 04:24:06 am
I had the same thoughts. Probably they changed the architecture and didn´t update the datasheet because for most people the electrical specifications are important not the architecture.  :-+
Title: Re: Transistors - die pictures
Post by: Noopy on February 27, 2024, 04:27:12 am
First additional information about the IRF3708:
It seems our thoughts were correct: International Rectifier changed their HEXFETs to "planar stripe HEXFET":
https://www.irf.com/pressroom/pressreleases/nr990728.html (https://www.irf.com/pressroom/pressreleases/nr990728.html)


(https://www.richis-lab.de/images/transistoren/b29x01.jpg)

Next: The Signetics NE543 is a servo motor driver. It supposedly corresponds to the WE3141, which was distributed by World Engines, a company from Cincinnati manufcaturing model kits. Perhaps the WE3141 was developed with Signetics and was later incorporated into the Signetics portfolio as the NE543.


(https://www.richis-lab.de/images/transistoren/b29x02.jpg)

There is a die in the housing, which also has bondpads in the centre. At the left edge of the die, you think you can recognise an image defect. However, this is actually a surprisingly wide edge.


(https://www.richis-lab.de/images/transistoren/b29x07.jpg)

(https://www.richis-lab.de/images/transistoren/b29x05.jpg)

(https://www.richis-lab.de/images/transistoren/b29x06.jpg)

It is difficult to visualise how slanted the edge actually is. It appears that the wafer was only cut very shallow and the rest was broken.


(https://www.richis-lab.de/images/transistoren/b29x04.jpg)

(https://www.richis-lab.de/images/transistoren/b29x08.jpg)

The dimensions of the die are 2,0mm x 1,8mm. On the right edge the characters 916A A are shown, presumably an internal project designation.


(https://www.richis-lab.de/images/transistoren/b29x03.jpg)

The datasheet shows a block diagram of the module and how it is usually wired. It is controlled with a square-wave signal via pin 4. The pulse width of the square-wave signal defines the setpoint position of the servomotor. Two inverters (yellow) process the input signal. The outputs of the inverters control a flip-flop (green) and are linked to the outputs of the flip-flop via NAND gates (purple). The lever of the servomotor is connected to a potentiometer. Depending on the current resistance value, the flip-flop generates pulses of different lengths. As a result, the NAND gates output pulses that are proportional to the deviation between the setpoint value and the actual value.

The NAND gates are followed by two circuits that extend the pulses of the flip-flop (cyan). The resistors Rs1 and Rs2 define by how much the pulses are extended. The resistors Rd1 and Rd2 ensure that the servomotor is only activated when there is a certain deviation between the setpoint and actual value. Finally, a second flip-flop (blue) realises the control of the two motor drivers (red), which represent an H-bridge. The resistors R8 and R9 improve the control behaviour of the circuit.


(https://www.richis-lab.de/images/transistoren/b29x09.jpg)

The datasheet also contains a circuit diagram of the module. The individual function blocks are highlighted here in the appropriate colours. An error has crept into the second buffer amplifier. Transistor Q2 has to be an NPN transistor. The circuit is largely self-explanatory. The only noticeable feature is the quadruple base contacting of the lowside transistors Q26/Q27 in the H-bridge.


(https://www.richis-lab.de/images/transistoren/b29x10.jpg)

The large H-bridge takes up more than half the area of the die. The transistors at the outputs of the pulse stretcher are just as prominent.


(https://www.richis-lab.de/images/transistoren/b29x11.jpg)

A closer look at the H-bridge shows that the circuit diagram does not quite reflect reality. The lowside transistors Q26 and Q27 each consist of two transistors. It is logical that each transistor has its own base resistor. However, it remains unclear why two base resistors have been integrated for each transistor.

The highside transistors Q24 and Q25 also each consist of two transistors. A PNP driver transistor is assigned to each highside transistor. However, the base potentials of the highside transistors are also connected in pairs.


https://www.richis-lab.de/BipolarA53.htm (https://www.richis-lab.de/BipolarA53.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 01, 2024, 03:43:42 pm
(https://www.richis-lab.de/images/transistoren/b30x01.jpg)

The 2N3878 is a fast NPN power transistor in a TO-66 package. It blocks up to 50V, whereby the collector-base blocking voltage is significantly higher at 120V. The collector current may be 4A continuously and 10A for short pulses. With a collector current of 4A, the amplification factor is still at least 20. Up to 35W can be dissipated through the housing. The cut-off frequency is specified at 40MHz. At 4A, the 2N3878 enables switching pulses with a duration of 1µs.


(https://www.richis-lab.de/images/transistoren/b30x05.jpg)

The advertisement shown here is from the magazine Electronics from 1965.


(https://www.richis-lab.de/images/transistoren/b30x02.jpg)

The transistor is placed on an unusual heatspreader. The electrical contact is made with sheet metal elements that have been pushed onto the pins and then have been soldered to them.


(https://www.richis-lab.de/images/transistoren/b30x06.jpg)

The heatspreader appears to have been soldered into the base plate.


(https://www.richis-lab.de/images/transistoren/b30x03.jpg)

(https://www.richis-lab.de/images/transistoren/b30x04.jpg)

The contact plates are soldered directly to the die. The base potential (on the right side) is fed into the emitter surface via the metal layer. These conductor tracks are slightly thinner than those of the emitter. The entire structure is coated with a clear protective lacquer.


(https://www.richis-lab.de/images/transistoren/b30x07.jpg)

The transistor has a MESA structure with edges that are not completely straight. The surface of the transistor is partially irregular. A faintly recognizable edge separates the emitter area from the base area.


(https://www.richis-lab.de/images/transistoren/b30x08.jpg)

The surface is damaged in one spot. This appears to be a scratch that extends from the upper line of the emitter area to the lower line of the base area. In the lower area, the silicon is also damaged in addition to the metallization. However, the damage does not extend to the junction.


(https://www.richis-lab.de/images/transistoren/b30x09.gif)

The base-emitter junction breaks down at -9V. The avalanche breakdown produces the familiar glowing dots. The current increases as follows: 10mA / 20mA / 30mA / 40mA / 50mA / 100mA / 200mA / 300mA / 400mA / 500mA

The light develops very evenly. However, the scratch seems to have an effect on the electric field. Below this artifact, the light spreads out late. In the lower left corner there are hardly any glowing islands. Since the metal layer with the base potential does not extend into this area, the resistance of the base-emitter path is higher there and the breakdowns in the areas with lower resistance remain dominant.


(https://www.richis-lab.de/images/transistoren/b30x10.gif)

The infrared image shows the relationships that are described in more detail with the SF137 (https://www.richis-lab.de/Bipolar75.htm (https://www.richis-lab.de/Bipolar75.htm)). In this image, the base current is 1A, while the collector current increases like this: 1A / 2A / 3A / 4A / 5A / 6A / 7A. The light initially only appears under the base area. As the collector current increases the light moves towards the emitter.


(https://www.richis-lab.de/images/transistoren/b30x11.gif)

In this picture, the base current is just 0,5A. While the collector current rises to 8A, the transistor leaves the saturation area. The resulting high thermal load ultimately destroys the structures, which is shown by the emitter contact lighting up.


(https://www.richis-lab.de/images/transistoren/b30x12.jpg)

(https://www.richis-lab.de/images/transistoren/b30x13.jpg)

The damaged area can only be guessed at by a small discoloration. The protective lacquer, which is torn at the emitter contact, disturbs the view on the surface of the transistor.


https://www.richis-lab.de/BipolarA54.htm (https://www.richis-lab.de/BipolarA54.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 22, 2024, 04:53:06 am
(https://www.richis-lab.de/images/transistoren/b31x01.jpg)

(https://www.richis-lab.de/images/transistoren/b31x03.jpg)

The International Rectifier IRLZ44 is a power MOSFET whose reverse voltage is specified at 60V. With a typical resistance of 28mΩ, a continuous drain current of 50A is permissible at room temperature. The IRLZ44 is a logic-level MOSFET. It achieves the resistance of 28mΩ at a gate-source voltage of 5V. For a gate-source voltage of 4V, the data sheet still specifies 39mΩ.

The marking can only be read easily with the correct illumination. The syntax and the layout of the marking match the representations often found in International Rectifier datasheets.


(https://www.richis-lab.de/images/transistoren/b31x04.jpg)

(https://www.richis-lab.de/images/transistoren/b31x05.jpg)

(https://www.richis-lab.de/images/transistoren/b31x06.jpg)

The die of the IRLZ44 is 3,6mm x 2,8mm. The gate potential is contacted on the left. The metal layer conducts the potential around the circumference of the transistor and also a little way into the center of the surface via two stubs.


(https://www.richis-lab.de/images/transistoren/b31x07.jpg)

As with many transistors from International Rectifier, several masks with numbers are shown on the upper edge. However, the structures are difficult to recognise here.


(https://www.richis-lab.de/images/transistoren/b31x08.jpg)

In the center of each edge is a small square of the metal layer. The purpose of these squares remains open, perhaps they facilitated the alignment of the masks or made it possible to check the alignment later.


(https://www.richis-lab.de/images/transistoren/b31x09.jpg)

A honeycomb structure can be seen in detail on the surface of the drain metal layer.


(https://www.richis-lab.de/images/transistoren/b31x02.jpg)

There is an older datasheet for the IRLZ44, according to which it is a third-generation HEXFET. In this datasheet, however, the device was not yet lead-free and lacked the index N. The P of this IRLZ44 shows that it is a lead-free device. An N is also appended to the designation. A more recent datasheet, which matches this marking, attributes the IRLZ44 to the fifth generation of HEXFETs. In any case, the honeycomb structure corresponds to the surface shown in the "International Rectifier HEXFET Databook".


https://www.richis-lab.de/FET38.htm (https://www.richis-lab.de/FET38.htm)

 :-/O
Title: Re: Transistors - die pictures
Post by: Noopy on March 22, 2024, 05:08:28 am
One addition to the whole topic:

This is a IRLZ44N!
The N version has a little lower Vds (55V vs. 60V), a little lower resistance and allows a little less current flow (47A vs. 50A).
Well it´s obviously the next generation, not the same...
Title: Re: Transistors - die pictures
Post by: MarkT on March 23, 2024, 10:22:30 am
Noopy, I see you opened up an RF power transistor above - the ceramic is likely BeO which is highly toxic if disrupted - its not a good idea to mess with these devices - you expressed amazement that the "ceramic" could handle the 195W rating - this strongly suggests it _is_ BeO which has very high thermal conductivity (can be better than aluminium, not quite as good as copper).  BeO is also a very high quality dielectric at RF, which is why it is chosen for RF devices despite the hazards.

If you aren't already taking precautions to avoid exposure to BeO fragments or dust, please do so, your health is more important than a few die pictures...
Title: Re: Transistors - die pictures
Post by: Noopy on March 23, 2024, 10:53:53 am
Thank you for your advice MarkT.
I have opened a lot of BeO devices. I know that BeO is problematic. In my view it´s ok to open such parts as long as you don´t break or grind the ceramic. I´m very cautious while opening such devices and I usually do it outside with a mask on.

 :-+