Author Topic: Transistors - die pictures  (Read 183121 times)

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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #500 on: November 11, 2021, 06:47:10 am »






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.




The die is quite big. The pins are properly separated.






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

 :-/O
 
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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #501 on: November 15, 2021, 04:38:51 am »


One more 2N3055, a Siemens 2N3055H. It looks like Siemens marked its 2N3055 similar to RCA (https://www.richis-lab.de/2N3055_08.htm): First all 2N3055 were hometaxial. With the new epitaxial 2N3055 the hometaxial were named 2N3055H.






Compared to the old Siemens 2N3055 (https://www.richis-lab.de/2N3055_01.htm) this one is really modern!  ;D




The die looks quite similar to the other hometaxial 2N3055.
But there is some interesting damage...




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

 :-/O
 
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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #502 on: November 21, 2021, 04:49:58 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.




A B * ? I don´t know what that means...








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.




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.




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.




The junction is a little messy and the metal layer is no aligned perfectly but it´s ok.




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

 :-/O
 
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Offline exe

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Re: Transistors - die pictures
« Reply #503 on: November 21, 2021, 06:24:33 pm »
No glowing pictures? :)
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #504 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.  ;)

Offline David Hess

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Re: Transistors - die pictures
« Reply #505 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.
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #506 on: November 29, 2021, 09:11:17 am »


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).






The pin holes looks a little sloppy.




A dry agent.






That´s an interesting pin conduct.






The design of the GT906 looks similar to the Philips AU103 (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.






The inner and the outer ring are connected to the base pin. The ring in the middle is connected to the emitter pin.




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).




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.






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

 :-/O


In addition I have updated:
2N1561 https://www.richis-lab.de/Bipolar17.htm
AU103 https://www.richis-lab.de/Bipolar03.htm
 
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Offline Miyuki

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Re: Transistors - die pictures
« Reply #507 on: November 29, 2021, 09:50:32 am »
Wow those weird patterns
It is so nice 🖤
 
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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #508 on: December 07, 2021, 04:32:14 am »


2N3055 built by SGS ATES (today ST Microelectronics).






The logo is really hard to identify.








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.




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/2N3055_15.htm

 :-/O
 
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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #509 on: December 08, 2021, 03:46:12 am »


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.






It looks a little older than the 2N3055.




The die took damage at the upper edge. Additional left of the left contact the coating is ruined.




Looks like there was a base collector flashover.


https://www.richis-lab.de/2N3055_16.htm

 :-/O
 
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Offline T3sl4co1l

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Re: Transistors - die pictures
« Reply #510 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?)

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Bringing a project to life?  Send me a message!
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #511 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.  :-//

Offline quadtech

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Re: Transistors - die pictures
« Reply #512 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
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #513 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

You are talking about the 1HT291Б (K1NT291B)?
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3651136/#msg3651136

Yes, this one is quite similar to the INT591A.

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #514 on: December 12, 2021, 04:23:52 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.




Quite a big drying agent disk.




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.




The connector pins were treated somehow and there are some fibers probably due to the treatment.





https://www.richis-lab.de/Bipolar85.htm

 :-/O
 
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Offline David Hess

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Re: Transistors - die pictures
« Reply #515 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.
 

Offline SeanB

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Re: Transistors - die pictures
« Reply #516 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.
 
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Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #517 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.  :-+

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #518 on: December 26, 2021, 04:11:27 am »


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.






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.






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

 :-/O
 
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Offline RoGeorge

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Re: Transistors - die pictures
« Reply #519 on: December 26, 2021, 09:50:26 am »
Wow, those tilted shots are amazing!   :-+
 
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Offline SilverSolder

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Re: Transistors - die pictures
« Reply #520 on: December 27, 2021, 03:22:29 pm »

Focus stacking taken to new heights!  :D
 

Offline David Hess

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Re: Transistors - die pictures
« Reply #521 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.
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #522 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
 
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Offline David Hess

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Re: Transistors - die pictures
« Reply #523 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.
 

Offline NoopyTopic starter

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Re: Transistors - die pictures
« Reply #524 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 :-+


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