G

GaAs

Gallium Arsenide. A III-V compound semiconductor material used for making optoelectronic devices and high-frequency ICs. GaAs has a higher electron mobility than silicon, thus having the capability of producing higher-speed devices. Electrons in GaAs travel at twice the speed of those of silicon.

GaAs FET

Gallium Arsenide Field Effect Transistor. A high-frequency voltage-controlled current amplifier similar to a silicon MOSFET. Also called GaAs MESFET (gallium arsenide metal semiconductor field effect transistor).

gate

(1) The control electrode in a field-effect transistor (FET). A voltage applied to the gate regulates the conducting properties of the semiconductor channel region, which is usually located directly beneath the gate. In a MESFET (metal semiconductor field effect transistor), the gate is in intimate contact with the semiconductor. In a MOSFET (metal oxide semiconductor field effect transistor), it is separated from the semiconductor by a thin oxide, typically 100-1000 angstroms thick. (2) A combination of transistors which form a circuit that performs a logic function, such as NAND or NOR. See also channel, drain, FET, MESFET, MOSFET and source.

gate array

A semicustom IC consisting of a regular arrangement of gates that are interconnected through one or more layers of metal to provide custom functions. Generally, gate arrays are preprocessed up to the first interconnect level so they can be quickly processed with final metal to meet a customer's specified function.

gate length

Physical distance between source and drain of a MOS transistor measured on the photomask plate. Also called "patterned" or "drawn" gate length. When determined from the actual transistor characteristics, called "effective" gate length. See source and drain.

gullwing

A common lead form used to interconnect surface mounted packages to the printed-circuit board.