Semiconductor History

Small changes having a big impact. Introduced in 1960, Philco had by then improved their etching process to create the thin base layer of their germanium alloy junction transistors. They then replaced the indium electrodes making the emitter and collector junctions with cadmium, giving better thermal dissipation. Due to its speed and thermal performance, it became widely used in computers of the time. These were manufactured by Philco (later Philco-Ford) at their factory in Spring City, PA. One AI processor chip now has more transistors than the first 25 years at least of the semiconductor industry!  It works, hfe (gain) is 96, Vf=273mV (so germanium).

Sinclair, TI and Philco Transistors Clive Sinclair formed Sinclair Radionics in 1961, having a good understanding of electronics and transistor manufacturing. Always the entrepreneur, he bought a quantity of transistor test failures from Semiconductors Limited (Semics) of Swindon. As seems to be the norm in British semiconductor history, it was convoluted. Semics was actually Plessey who had licensed Micro Alloy Diffused Transistor technology from Philco in the US. Sinclair used the transistors in a very small pre-amplifier and sold both the amplifier and retested/re-badged transistors separately. Later on he must have done this again as ST140 and ST141 transistors were on the market, albeit probably in relatively small quantities again. Above left is an ST140 Sinclair transistor. There is also an original Philco MADT transistor on the right. In the middle is a UK manufactured Texas Instruments transistor. Texas Instruments opened a semiconductor plant in Bedford, UK in 1960 to ...