The Point-Contact Transistor

On 23 December 1947, in a basement laboratory at AT&T Bell Labs in Murray Hill, New Jersey, John Bardeen and Walter Brattain demonstrated signal amplification using a small device built from a germanium crystal and two gold-foil contacts. Only a handful of researchers, William Shockley among them, witnessed it.

That small device—later named the transistor—was the starting point of every piece of electronics built in the second half of the twentieth century.

Replacing the Tube

Until then, the only way to amplify an electronic signal was the vacuum tube. Radio, television, computers—the ENIAC (1945) used about 17,000 of them. Several failed every hour of operation; mean time between failures was measured in hours. The heat was enormous, the power draw vast.

A solid-state replacement had been pursued at several institutions since before the war. At Bell Labs, a small group under Shockley had been systematically studying the electrical properties of semiconductors—initially silicon, then germanium.

The breakthrough leading to the 23 December demonstration came from Bardeen's organisation of the theory of surface states, Brattain's experimental confirmation of it, and the manual technique developed in the final days for placing two gold contacts onto a germanium surface in extreme proximity.

"Trans-Resistor"

The name 'transistor' was coined by the Bell Labs engineer John R. Pierce from 'trans-conductance' and 'resistor'. The lab kept the invention classified until the official announcement in June 1948.

The first transistors were primitive by today's standards. Point-contact devices were unstable and not suited to mass production. The 1948 junction transistor, proposed by Shockley independently, became the design that could be commercially manufactured.

The Three

In 1956, Bardeen, Brattain, and Shockley shared the Nobel Prize in Physics. The relationship among them was not, however, easy.

Shockley had witnessed the 23 December demonstration but had not been directly involved in the device itself. His own field-effect proposal had not yet worked. He nonetheless made himself the public face of the announcement, and Bardeen and Brattain resented it for years. Both eventually left Bell Labs.

In 1956 Shockley founded Shockley Semiconductor Laboratory in Mountain View, California. The young researchers he hired could not bear his management style; in 1957 they left in a group and founded Fairchild Semiconductor. Out of Fairchild, in 1968, came Intel, AMD, and National Semiconductor. The geographic concentration later called Silicon Valley began on the patch of land Shockley had picked.

Seventy Years of Miniaturisation

The first transistor was a few millimetres long, a handmade device of germanium and gold foil.

In 2026, TSMC manufactures advanced logic transistors at a 3-nanometre gate length. A single chip holds more than 100 billion transistors. From that one device on 23 December 1947, integration density has multiplied by roughly $10^17$—a hundred quadrillion times—in something under eighty years.

Moore's Law, the empirical rule, predicted a doubling roughly every eighteen months. From 1947 to 2026, that comes to about 53 doublings. $2^53$ is approximately $10^16$. Theory and observation agree, more or less.