Semi-Insulating Gallium Arsenide for Microwave and Millimeter-Wave Device Applications,

Abstract : A wide variety of semiconductor devices utilizing gallium arsenide (GaAs) are currently under development by the Army for use in secure communication and improved surveillance systems. GaAs is a semiconductor material characterized by a very high electron mobility, a direct band gap of 1.43 eV, and a high intrinsic resistivity (approximately equal to ten to the 8th power ohm/cm). The low field mobility of electrons in GaAs is one of its greatest attributes and offers high frequency operation in devices such as the field effect transistor (FET). The GaAs FET, a critical component in emerging military systems, is experiencing a rapidly expanding use in oscillator, mixer, logic element, power amplification, and low noise/high gain applications. This device threatens to replace virtually all low noise traveling wave tubes at frequencies from 4 to 30 GHz; is an attractive substitute for difficult to manufacture devices such as Gunn diodes for 4 to 8 GHz operation; and, monolithically fabricated as logic gates, can function at speeds to 10 GHz. In general then, GaAs FET's will eventually replace device configurations of more complex circuitry. However, its full potential has not been realized, largely due to the chronic material problems experienced by device manufacturers.