EARLY GERMANIUM POWER TRANSISTOR DEVELOPMENT Neville Fletcher
Oral History – Neville Fletcher (Continued) both uniform compositions and layered structures for NPN transistors. They were making point contact diodes and transistors, NPN grown junction transistors, and later PNP transistors (including my power transistors), and alloy junction high voltage diodes. I was involved with most of these operations, but I didn’t have any management responsibility. I also remember details of the basic equipment used for reduction of germanium dioxide to germanium, zone leveling, crystal growth, sawing, grinding, etching, dicing, encapsulation, etc, since the place wasn’t very big and I had some hands-on experience with all this equipment. This was basic to the diode and NPN transistor programs that were running in 1953 when I was first involved. As I recall it, the main products at the time were point contact transistors, UHF diodes, and grown junction NPN transistors, with a start made on PNP alloy junction transistors. Much of the work was guided by several thick manuals published by Bell Labs. I can’t remember much detail of what was in them. As with most TP products, the point contact transistors were made on a fairly “manual” production line and then were adjusted and had the point contacts “formed” (by discharging a capacitor) at the end. After this, they were tested and sorted into	Oral History – Neville Fletcher (Continued) different categories on the basis of breakdown voltage and current amplification factor. There were, I think, three bins for the final product, and the transistors were given different numbers on the basis of their performance. While I was familiar with the production line at the time, and remember things such as the nice little machine for putting the kinks in the point contact wires, I was not personally involved. The photo above shows one of the TP point contact transistors mentioned by Professor Fletcher in the Oral History. This particular unit is dated Apr 27, 1954. Transistor Products was one of the small number of companies to actually manufacture point contact transistors – this was the initial transistor type first developed at Bell Labs, and was licensed to only a few companies willing to pay the $25,000 required for manufacturing rights. Point contact transistors were difficult to manufacture, noisy and not tolerant of physical shock. Junction technology, such as used in the X78, replaced point contact transistors in the mid 1950s. Go To Fletcher Oral History, Page 5
COPYRIGHT © 2003 by Jack Ward. All Rights Reserved. http://www.transistormuseum.com/ PAGE 4