The Road to Silicon Valley
Wednesday, 23 June 2010
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The Road to Silicon Valley
Point contact transistor
Fairchild Semiconductors

Despite the improvements in materials science, the research group at Bell still concentrated on the field effect theory put forward by Shockley but they had no luck in producing an amplifying device. It is generally assumed that they gave up and moved on to invent the transistor as we know it today, but this isn’t so.

They actually succeeded in building a field effect transistor in the week before Christmas 1947 but it would only work immersed in an insulating liquid. A few days later they managed to make the device work, with a drop of water acting as the gate, on a slab of silicon. It worked but it clearly wasn’t a practical device!

Four days later they manage to create a workable prototype point contact transistor that was dry. The trick was to place two metal contacts very close together on a bar of silicon. The device was the first transistor but it wasn’t perfect. The need to make two metal contacts so close together made the device unreliable.

point

The first point contact transistor

Shockley believed that it was possible to build a better device - possibly still based on the field effect. Soon after the announcement of the point contact transistor in 1947 Shockley abandoned his search for a field effect transistor and settled on the now familiar pnp sandwich arrangement of the bipolar transistor. He thought it would work but he couldn’t verify his ideas simply because there was no way to build it!

It took three more years before the necessary materials science caught up with Shockley’s ideas. Gordon Teal and John Little, working at Bell Labs, had managed to develop methods of pulling doped crystals from a melt. At the time other workers argued that large perfect crystals of silicon were unnecessary and would always be to expensive to work with - but Teal carried on. In 1950 he managed to produce an ingot doped first as p type, then as n type and finally as p type. When this was sliced up the result was a large number of  Shockley’s pnp junctions and the era of the modern transistor had started. The junction transistor was more reliable, produced less noise and could handle more power than the point contact transistor.

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Bell had now sold 35 licences world-wide to the new technology and suddenly every electronics company was keen to learn about the new transistor. Gordon Teal left Bell Labs and went to a small company based in Dallas. Texas Instruments was late into the field but with Teal they rapidly built a semiconductor lab and production facility. They were first in 1954 with the fabrication of a silicon transistor. All previous devices had been based on germanium and silicon, with a higher melting point was much better at handling power than germanium.

It is only chance that Silicon Valley didn’t grow in the wide open plains of Texas rather than California - but it didn’t. What they did do was demonstrate that any small company with enough enthusiasm could get years ahead of the established competition in the rapidly changing world of solid state electronics.

At the same time that TI announced the first silicon transistors William Shockley left Bell Labs to start his own semiconductor business. At first he found funding difficult to obtain but eventually he secured the backing of Beckman Instruments and he set up Shockley Semicondutor in Palo Alto - the first silicon company in Silicon Valley. His reputation was so good that he attracted some of the best young talents available at the time including Gordon Moore, a physical chemist; Robert Noyce, a physicist and Jean Hoerni, also a physicist .

The prospects for the company should have been good but Shockley was not a good manager and he failed to focus on a product line. In particular he insisted on pursuing a four-layer pnpn avalanche diode which was way too far ahead of its time. In 1957 a group of Shockley’s engineers approached Beckman in an effort to oust Shockley as manager. Unfortunately Beckman couldn’t do very much because Shockley had just been awarded the Nobel Prize for his work on transistor action and was riding high on a wave of publicity.

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Last Updated ( Wednesday, 16 November 2011 )
 
 

   
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