Glossary / Semiconductors
MOS transistor
A transistor built from a metal electrode, an oxide layer and a semiconductor, in which a voltage on the electrode alone opens and closes the channel. Most of today's chips are made of these.
Applying a voltage to an electrode across a thin insulating oxide creates a conducting channel in the semiconductor beneath. Switching draws almost no current, so huge numbers can be packed together without overheating. Dawon Kahng and Mohamed Atalla at Bell Labs made one work in 1960 and patented it[1].
The idea appears in Julius Lilienfeld's 1926 patent, but surfaces could not then be made clean enough. The MOS transistor later came to dominate the industry because it gets better as it gets smaller[2].
Related terms
- TransistorA semiconductor device in which a small signal controls a larger current, so it can amplify or switch. The basic component of all electronics.
- CMOSA circuit style that pairs the two opposite types of MOS transistor. Current flows only at the moment of switching, so power consumption is tiny.
- Dennard scalingThe design rule that shrinking a transistor's dimensions and voltage by the same factor makes it faster and more efficient while keeping heat per unit area constant.