Exposition
Technological Evolution
Bipolar transistors and MOS
(1960) The bipolar transistor is based on the semiconductor principle, popularized by A. H. Wilson in 1931. Shockley, Bardeen and Brattain discovered and published the transistor effect in 1948. They were awarded the 1956 Nobel Prize for Physics for their discovery.
The word transistor is a combination of the terms TRANSfer resISTOR , as, under some conditions of polarization, a weak input current is able to control the flow of an output current that is several times larger.
This current has both negative and positive polarity and is hence termed bipolar. A decade-long development and improvement effort was necessary to make transistors a better alternative to vacuum tubes.
Kang and Atalla managed to construct the first metal oxide semiconductor (MOS), also called unipolar, transistor at Bell Labs in 1960. They generated electrical flows formed by a single type of carriers. Unlike bipolar transistors, the MOS transistor is a voltage rather than a current-controlled device. This affords high control rates with low power consumption.
MOS technology manufacturing process improvements have considerably reduced transistor sizes. The first integrated MOS subsystems for use in computer construction were released in the early 1970s.
MOS transistors are the core of today’s computer systems.