William Shockley and solid state electronics
Tuesday, 18 May 2010
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William Shockley and solid state electronics
The transistor
Beyond success

 

The transistor age had been born in a scene that mimicked Bell's original invention of the telephone.

The point contact transistor wasn't practical, however. Even Brattain had to admit that he first positioned the wires then fiddled until the device worked. This was no way to build the components that the computer industry would need by the million!

Shockley was sad and frustrated that he had had so little direct input into the creation of the first transistor - impractical though it was. He wrote,

"My elation with the group's success was tempered. I experienced some frustration that my personal efforts had not resulted in a significant inventive contribution of my own."

Still  Shockley was always included in photos as the co-discoverer of the point contact transistor.

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The three inventors of the transistor - from left to right Bardeen, Brattain and Shockley.


Shockley now knew that a solid state amplifying device was possible and he needed to find a way to make it practical.

For five weeks after the invention of the point contact transistor he thought hard and on New Year's Eve 1947 he filled 19 pages of his lab book with basic ideas. By the 23rd of January he had the construction of the junction transistor more or less completed.

Instead of a pair of wires to inject holes a third region of semi-conductor was used - creating an NPN sandwich. The first region acts as the source or emitter, the middle region controls the current through the entire device and acts as a control grid or base, the third is the collector. A small current flowing between base and collector causes a much larger current to flow between the emitter and collector - this makes the transistor a current amplifier.

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The junction transistor is relatively easy to make once you know how to handle the semi-conductor materials. Shockley, Bardeen and Brattain applied for a joint patent in 1948 on the technology.  Bell licensed the design to any company who would pay $25,000 - a bargain given that they also offered help on getting the manufacturing right. The licence was waived to any company manufacturing hearing aids - a concession to Alexander Graham Bell's original work with the deaf.  The cheap licence was partly altruism and partly to stave off an anti-trust action like the one in progress against AT&T.

The rest of this part of the story you will already know. In 1953 the first transistor hearing aids were produced, in 1954 the transistor radio was invented and in 1956 IBM started to build the transistor replacement for the SAGE air defence computer. The military wasn't too keen to have its brand new 55,000 valve computer replaced and so the first transistorised computers were actually brought to the market by Univac and Philco in 1957.

From there the pace increased rapidly. Silicon took over from Germanium as the semiconductor of choice and the integrated circuit was invented. But the junction transistor was the first practical step. Without Shockley the discovery would still have happened. Other groups were only months behind the Bell Labs team - but for once there is little doubt about who was first.

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At first it wasn't obvious how to package transistors to make best use of their size advantage. Early transistor modules featured lots of empty space!

 

In 1955 Shockley did the almost unheard of thing for a Bell Labs employee - he left to form his own company. A small shed housed Shockley Semiconductors in the area south of Palo Alto that would become known as Silicon Valley.

He hoped to make use of his knowledge of semi-conductors to build better transistors but he took a wrong turn in choosing to work with a four-layer PNPN structure. The four layer switch was generally thought to be a dead end at the time - although eventually it turned out to be quite useful - but Shockley would have been better off working on silicon rather than germanium transistors. The operation was far from a success but from it grew many of the companies that eventually filled Silicon Valley.

Shockley shared the Nobel prize with Bardeen and Brattain  in 1956. A Swedish journalist tried to phone Shockley early in the morning but the line was so bad he thought that someone was trying to play a joke on him. Soon afterwards it was announced on the radio and Shockley drove to the lab and took everyone out for a champagne breakfast.

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Last Updated ( Tuesday, 18 May 2010 )
 
 

   
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