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Transistors - die pictures

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Noopy:
Since the structures are quite rude it is very likely the specifications suffered during the decades. But I didn´t do measurements. I urgently need a SMU.  ;D

Noopy:




The last transistors from the estate of Professor Heinz Beneking. There are five transistors in a plastic box. The sticky label reveals that these are npn transistors based on gallium arsenide. Gallium arsenide makes it possible to achieve significantly higher switching frequencies compared to silicon.




The transistors are labeled with a letter and one or two numbers. The label describes an operating point at 3V and 3mA for each transistor.




The marking appears to have been applied by hand.




There is a bondwire on the bottom of the package. It can be assumed that the transistor was bonded by hand.




The edge length of the die is approximately 0,65 mm. The large lower contact transfers the substrate potential and thus the collector potential. The contours of the base and emitter areas can just be seen in the middle of the die. Test structures appear to have been integrated in the upper third.


https://www.richis-lab.de/BipolarA68.htm

 :-/O

Noopy:


The TF65 is an early germanium transistor that was originally developed by Siemens. The model shown here was produced by the German company Intermetall. There is no datasheet from Intermetall. Siemens offered several types, including a TF65 and several TF65/30. The maximum blocking voltage of the TF65/30 is 10V. The maximum permissible collector current is 50mA. Up to 30mW can be dissipated via the housing. Amplification factors from 20 to 100 can be distinguished using six color codes. Red stands for an amplification factor of 20 to 30. The TF65 without the addition 30 is not sorted according to amplification and allows a slightly higher reverse voltage of 16V. However, the maximum permissible power dissipation is 5mW lower than for the TF65/30.




The package contains a gel. Such fillings usually have two functions. They protect the transistor from environmental conditions and support the dissipation of power loss to the housing.




The transistor is constructed like most alloy transistors. A metal strip carries a 0,13 mm thick n-doped germanium disk, which is contacted on both sides with a solder. The solder usually contains indium, which is alloyed into the germanium to create a p-type doping.






The germanium crystal has a diameter of 2,1mm and it is broken in several places. The construction was not mechanically stressed when it was opened. The reason for the destruction could have been an electrical overload. Such an overload can heat the germanium crystal to such an extent that the thermomechanical stresses burst it.




The surface of the germanium crystal shows the typical structure that often occurs during etching. The crystal was obviously etched even thinner in the direct vicinity of the contact. The surface structure is also smoother there.


https://www.richis-lab.de/BipolarA69.htm

 :-/O

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