Transistor

The winter of 1947 saw the birth of an innovation that would transform our relationship with technology. At Bell Labs, three men—John Bardeen, Walter Brattain, and William Shockley—designed the transistor, a tiny device whose significance no one yet suspected. Their work would earn them the Nobel Prize in Physics in 1956.

This discovery was no accident. As early as the 1930s, Mervin Kelly, director of research at Bell Labs, had anticipated the limitations of vacuum tubes that equipped all electronic devices. These tubes, as fragile as glass, consumed enormous amounts of energy and occupied considerable space. Kelly sought an alternative and invested in semiconductors, materials halfway between conductors and insulators, then poorly understood by the scientific community.

To explore this path, Kelly patiently built a multidisciplinary team. He recruited William Shockley and Dean Woolbridge in 1936, then James Fisk and Charles Townes three years later. Walter Brattain, already at Bell Labs since 1929, joined the venture. The team held seminars to decipher semiconductor physics. Their initial experiments with copper oxide came to nothing. At the dawn of the war, Russell Ohl proposed focusing on silicon.

The world conflict accelerated this research. Radars required frequencies too high for vacuum tubes. Germanium and silicon were ideal candidates, especially since the military funded sophisticated purification techniques for these materials. In 1945, Kelly restructured his laboratories and created a section dedicated to solid-state physics under Shockley’s leadership. The team expanded to include Walter Brattain, Gerald Pearson, and the newly recruited John Bardeen.

The autumn of 1947 saw a remarkable acceleration in their work, a period Shockley would later call the "magic month." On November 17, Brattain and Ralph Gibney discovered that a semiconductor device immersed in an electrolyte produced an amplification effect. Experiments followed in rapid succession with germanium. On December 16, 1947, Bardeen and Brattain achieved significant amplification with a device featuring two closely spaced contact points. The transistor had just been born.

The story unfolded in the following weeks. Between December 1947 and February 1948, Shockley developed the theory of the junction transistor, which would prove industrially viable. He understood that amplification came from an injection of minority charge carriers and envisioned a sandwich of three semiconductor layers. On February 23, 1948, an experiment by John Shive brilliantly validated this hypothesis.

Manufacturing the first junction transistor as Shockley had imagined required two additional years of development. Gordon Teal and Morgan Sparks succeeded in April 1950, thanks to metallurgical innovations. In November 1950, Shockley published Electrons and Holes in Semiconductors, an instant bible for scientists in the field.

The transistor’s first applications surprised its creators. AT&T’s telephone networks, though responsible for the invention, only adopted this technology in the late 1950s. Transistors, however, conquered portable radios, hearing aids, and especially the military. The Minuteman missile program (1958-1962) integrated transistors into its computer guidance system.

Transistorized computers emerged in the early 1950s. Bell Labs designed TRADIC, the first airborne transistor computer. IBM launched its transistorized calculator, the model 608, in 1957. Philco commercialized its TRANSAC computers based on its surface-barrier transistor technology. Texas Instruments, General Electric, and RCA offered transistors specifically designed for computing.

This technological transformation also revolutionized production methods. Fairchild Semiconductor, founded in 1957 by eight defectors from Shockley’s company, including Gordon Moore and Robert Noyce, invented new manufacturing methods. These innovations gradually shaped what would become Silicon Valley, the global epicenter of the semiconductor industry.