The transistor was invented in 1947 by a team that included William Shockley (1910–1989), Walter H. Brattain (1902–1987), and John Bardeen (1908–1991). In 1956 the three men received the Nobel Prize in physics for the development.
Later close study of the invention has tended to minimize the role of Shockley, suggesting that he insisted on remaining in charge of the project to share credit, even though his contributions were minimal and superseded by the contributions of the other two researchers. Shockley later published and spoke about his views on the question of genetically acquired intelligence, leading many critics to charge that he was a racist. Shockley’s unpopular views on this sensitive issue contributed to the reexamination by historians of his role in the transistor invention.
Before World War II, the director of research at Bell Labs established a team to study solid-state physics, putting Shockley and S. O. Morgan in charge of the research. That team speculated that it would be possible to control the flow of electrons inside a semiconductor by imposing an outside electric field. Semiconductors included materials such as germanium and silicon that could strengthen a current, conduct a current, or resist a current. If turning on and off an outside field could prevent the current flow, small semiconductor pieces controlled by surrounding electric fields could be used as switches and amplifiers in electric circuits. During World War II, silicon was used in radar as a detector, and some knowledge about the material was accumulated.
After the war, Shockley assembled a team to work on the project. The original idea to use silicon as an amplifier did not work, as the surrounding electric field did not penetrate into the interior of the semiconductor. John Bardeen, who was trained as a theoretical physicist, proposed that the surface of the material accounted for the lack of penetration and developed a set of predictions about the behavior of semiconductors. Walter Brattain observed that a field would penetrate the semiconductor if it were applied through an electrolyte on the surface of the semiconductor. Later experiments and a series of unexpected results led to coating the semiconductor with a rectifying metal directly wired to the switching system and to the conclusion that a pointcontact system worked properly, quite different from the electric-field system originally proposed. The “point contact resistor,” dubbed the transistor, was the result, and Bell Labs announced and patented the invention in 1948.
The transistor was able to achieve the same function as the vacuum tube with less space and without generating heat. Later refinements and miniaturization led to even smaller integrated circuits and to the computer chip.By the early 1970s, the transistor had largely superseded the vacuum tube and had become a staple product of the electronics industry, with literally billions produced annually. Transistors not only replaced the vacuum tube in radio and television equipment but also
were employed in computers, logic and switching circuits, in medical electronic devices, in miniaturized calculators and computers, and in numerical controlled machines employed in manufacturing industries.