Dec. 23, 1947: Transistor Opens Door to Digital Future

Thursday, 23 December 2010 13:00

Dec. 23, 1947: Transistor Opens Door to Digital Future

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1947: John Bardeen and Walter Brattain, with support from colleague William Shockley, demonstrate the transistor at Bell Laboratories in Murray Hill, New Jersey.

It’s been called the most important invention of the 20th century. The transistor, aka point-contact transistor, is a

semiconductor device that can amplify or switch electrical signals. It was developed to replace vacuum tubes.

Vacuum tubes were bulky, unreliable and consumed too much power. So AT&T’s research-and-development arm, Bell Labs, started a project to find an alternative.

For nearly a decade before the first transistor was developed, Shockley, a physicist at Bell Labs, worked on the theory of such a device. But Shockley couldn’t build a working model. His first semiconductor amplifier had a “small cylinder coated thinly with silicon, mounted close to a small, metal plate.”

So Shockley asked his colleagues, Bardeen and Brattain, to step in. One of the problems they noticed with Shockley’s first attempt was condensation on the silicon. So they submerged it in water and suggested the initial prototype have a metal point “that would be pushed into the silicon surrounded by distilled water.” At last there was amplification — but disappointingly, at a trivial level.

Following more experiments, germanium replaced silicon, which increased amplification by about 300 times.

A few more modifications later, Brattain had a gold metal point extended into the germanium. That resulted in better ability to modulate amplification at all frequencies.

The final design of a point-contact transistor had two gold contacts lightly touching a germanium crystal that was on a metal plate connected to a voltage source. Also known as the “little plastic triangle,” it became the first working solid-state amplifier.

Bardeen and Brattain demonstrated the transistor device to Bell Lab officials Dec. 23, 1947. Shockley was reported to have called it “a magnificent Christmas present.” But Shockley himself was not present when it happened and was said to be bitter over losing out on that day.

He had his revenge, though. Shockley continued to work on the idea and refine it. In early 1948, he came up with the bipolar or junction transistor, a superior device that took over from the point-contact type.

Bell Labs publicly announced the first transistor at a press conference in New York on June 30, 1948.

The transistor went to replace bulky vacuum tubes and mechanical relays. The invention revolutionized the world of electronics and became the basic building block upon which all modern computer technology rests.

Shockley, Bardeen and Brattain shared the 1956 Nobel Prize in Physics for the transistor, but the trio never worked together after the first few months of their initial creation of the transistor.

Shockley left Bell Labs and founded Shockley Semiconductor in Mountain View, California — one of the early high-tech companies in what would later become Silicon Valley.

Brattain remained a fellow at Bell Labs. Bardeen became a professor at the University of Illinois in 1951, and he shared a second Nobel Prize in Physics in 1972, for the first successful explanation of superconductivity.

Source: Various

Photo: William Shockley, John Bardeen and Walter Brattain work at Bell Labs in the late 1940s.
Courtesy Alcatel-Lucent/Bell Labs

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