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Diodes - die pictures

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Noopy:
In this topic I will post pictures of diodes. You can find the overview here: https://www.richis-lab.de/Diode.htm

I have already a BAV45 (https://www.richis-lab.de/Diode01.htm) and a lot of zenerdiodes in the voltage reference section (https://www.richis-lab.de/REF00.htm).




Today 1N4007, everybody knows it.  :clap: ;D
1000V / 1A




The die is protected with some white potting.




The die is 0,2mm thick.




0,93mm x 0,95mm
Both surfaces are completely covered with tin.




That is an interesting picture. On the side of the die there is an unsteady crossover (upper part is 0,04mm, lower part is 0,13mm). I assume that is the border of an epitaxial layer. I assume there was an n+ wafer then they added an epitaxial n layer to get high voltage ratings and then they added a p layer. Either they diffused the p doping or there was another epitaxial step. At the lower end of the die edge there could be another unsteady crossover. Can´t be sure...  :-/O


https://www.richis-lab.de/Diode02.htm

 :-/O

RoGeorge:
Thank you, subscribed!   :)

T3sl4co1l:
Drop it in acid, see if there's any patterning on top?

I suspect old diodes like those, won't have much (probably just guard rings?), but some power schottky are made with fine cells like MOSFETs. Should be interesting to see.

Tim

Noopy:

--- Quote from: T3sl4co1l on June 04, 2021, 09:13:46 pm ---Drop it in acid, see if there's any patterning on top?

--- End quote ---

Good idea!  :-+ Unfortunately I have lost the die. ::) Will have to decap one more 1N4007.



--- Quote from: T3sl4co1l on June 04, 2021, 09:13:46 pm ---I suspect old diodes like those, won't have much (probably just guard rings?), but some power schottky are made with fine cells like MOSFETs. Should be interesting to see.

--- End quote ---

I´m pretty sure the 1N4007 has nothing like that.
I have taken pictures of two IGBTs and their freewheeling diodes:








International Rectifier IRG4PH40K
https://www.richis-lab.de/Bipolar35.htm






IXYS IXGH48N60C3D1
https://www.richis-lab.de/Bipolar26.htm


And of course the darlington power modules:






Powerex KD324510
https://www.richis-lab.de/Bipolar19.htm




Gleichrichterwerk Stahnsdorf SU510
https://www.richis-lab.de/Bipolar24.htm


But I will have to get a power schottky...  :-/O ;D

David Hess:
High voltage diodes like the 1N4007 usually have a PIN structure but I do not know that it will be apparent.  They can work in place of dedicated RF PIN diodes.

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