History
The transistor is one of the most important inventions of the twentieth century. It emerged from decades of work on crystal rectifiers, quantum mechanics, semiconductor materials, surface physics, and the desire to replace vacuum tubes in telephone systems.
- Early 1900s — Crystal detectors. Radio experimenters used semiconductor crystals such as galena as rectifiers. These “cat's-whisker” detectors proved that useful electronic behavior could occur in a solid without a heated cathode.
- 1920s–1930s — Field-effect ideas. Julius Lilienfeld and later Oskar Heil patented concepts in which an electric field would control current in a semiconductor. Manufacturing and surface-state problems prevented a successful practical device at the time.
- 1940 — Silicon PN junction. Russell Ohl at Bell Labs discovered a silicon junction with strong rectifying and photovoltaic behavior. Understanding controlled P- and N-type regions became central to later semiconductor devices.
- December 1947 — Point-contact transistor. John Bardeen and Walter Brattain demonstrated transistor action at Bell Laboratories while working in William Shockley's group. Their germanium point-contact device showed that a small electrical input could control and amplify current in a solid.
- 1948 — Public announcement. Bell Labs publicly announced the transistor in June 1948 and began licensing the technology to other manufacturers.
- 1948–1951 — Junction transistor. Shockley developed the theory of the bipolar junction transistor, which proved easier to manufacture reliably than the delicate point-contact form.
- 1950s — Germanium to silicon. Early commercial transistors were commonly germanium. Improved purification, crystal growth, diffusion, and oxide technology allowed silicon to dominate because of its temperature behavior and manufacturing advantages.
- 1954 — Transistor radio era. The Regency TR-1 became the first widely marketed commercial transistor radio, demonstrating the practical advantage of small, battery-powered solid-state electronics.
- 1956 — Nobel Prize. Bardeen, Brattain, and Shockley shared the Nobel Prize in Physics for their research on semiconductors and discovery of the transistor effect.
- 1959 — Planar process. Jean Hoerni at Fairchild developed the planar process, leaving a protective silicon-dioxide layer over semiconductor junctions. This greatly improved reliability and manufacturing.
- 1959–1960 — MOSFET. At Bell Labs, Mohamed Atalla's silicon-surface work and Dawon Kahng's device fabrication produced the first successful MOS field-effect transistor. The MOS structure eventually became the dominant transistor of integrated digital electronics.
- 1960s — Integrated circuits. Transistors, resistors, diodes, and interconnections could be fabricated together on one silicon chip. The transistor stopped being only a discrete component and became a repeated microscopic building block.
- 1970s onward — MOS scaling. MOS transistors became smaller, faster, and cheaper. Microprocessors, memories, calculators, digital watches, and eventually personal computers and mobile devices followed.
- Modern era. Individual chips now contain enormous numbers of MOS transistors, while specialized discrete BJTs, JFETs, MOSFETs, IGBTs, GaN devices, and SiC devices remain important wherever voltage, current, noise, speed, or power demand special structures.
A change in scale
A vacuum tube might occupy centimeters and require several watts just to heat its cathode. A modern integrated transistor may be microscopic and require no heater at all. That difference allowed electronic systems to move from racks of equipment to pocket radios, then to integrated circuits and complete computers on a chip.