CMOS

related topics
{system, computer, user}
{acid, form, water}
{math, energy, light}
{@card@, make, design}
{language, word, form}
{style, bgcolor, rowspan}
{water, park, boat}
{rate, high, increase}

Complementary metal–oxide–semiconductor (CMOS) (pronounced /ˈsiːmɒs/) is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also used for several analog circuits such as image sensors, data converters, and highly integrated transceivers for many types of communication. Frank Wanlass patented CMOS in 1967 (US patent 3,356,858).

CMOS is also sometimes referred to as complementary-symmetry metal–oxide–semiconductor (or COS-MOS[1]). The words "complementary-symmetry" refer to the fact that the typical digital design style with CMOS uses complementary and symmetrical pairs of p-type and n-type metal oxide semiconductor field effect transistors (MOSFETs) for logic functions.

Two important characteristics of CMOS devices are high noise immunity and low static power consumption. Significant power is only drawn while the transistors in the CMOS device are switching between on and off states. Consequently, CMOS devices do not produce as much waste heat as other forms of logic, for example transistor-transistor logic (TTL) or NMOS logic, which uses all n-channel devices without p-channel devices. CMOS also allows a high density of logic functions on a chip. It was primarily this reason why CMOS won the race in the eighties and became the most used technology to be implemented in VLSI chips.

The phrase "metal–oxide–semiconductor" is a reference to the physical structure of certain field-effect transistors, having a metal gate electrode placed on top of an oxide insulator, which in turn is on top of a semiconductor material. Aluminum was once used but now the material is polysilicon. Other metal gates have made a comeback with the advent of high-k dielectric materials in the CMOS process, as announced by IBM and Intel for the 45 nanometer node and beyond.[2]

Contents

Full article ▸

related documents
Industry Standard Architecture
Superheterodyne receiver
Computer data storage
PowerBook
Data General Nova
History of Microsoft Windows
AirPort
Random-access memory
OSI model
Transmitter
Mac OS
Non-linear editing system
Crossbar switch
Peripheral Component Interconnect
Adobe Flash
Transistor
MiniDisc
Amiga Original chipset
AppleTalk
Apple IIe
MS-DOS
Citizens' band radio
Virtual private network
Cable modem
Car audio
MPEG-2
PowerPC
Closed captioning
Direct memory access
Digital video