Transistor

A transistor is a device used to amplify or switch electronic signals and electrical power. Transistors are one of the basic building blocks of electronics.

The first to be built was in 1947 by John Bardeen and Walter Brattain while working under William Shockley at Bell Labs. The three shared the 1956 Nobel Prize in Physics. They are usually made from pure silicon or germanium. Transistors revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things.

Compared with the vacuum tube, transistors are generally smaller and require less power to operate. They were originally packaged individually, but were subsequently embedded into integrated circuits (IC). Jack Kilby won the Nobel Prize for Physics for his part in the invention of the IC. This led to Very Large-Scale Integration (VLSI) which is the process of creating an IC by combining millions of MOS transistors onto a single chip. The microprocessor and memory chips are VLSI devices, but now CPU, GPU, ROM and RAM can be combined into one VLSI chip.

The MOSFET (metal–oxide–semiconductor field-effect transistor), also known as the MOS transistor, is by far the most widely used transistor, used in applications ranging from computers and electronics to communications technology such as smartphones. The MOSFET has been considered to be the most important transistor, possibly the most important invention in electronics, and the birth of modern electronics. MOSFETs are the most numerously produced artificial objects ever with more than 13 sextillion (13x1021) MOSFETs manufactured between 1960 and 2018.

The CNTFET (carbon nanotube field-effect transistor) uses carbon nanotubes as the channel material instead of bulk silicon in the traditional MOSFET structure. They have twice the carrier velocity over MOSFETs and about four times higher transconductance. However, MOSFETs are still preferred due to higher reliability and cheaper production cost.

Moore's law is the observation that the number of transistors in a dense IC doubles about every two years.

See also: Historical transistor count and semiconductor scale examples.