Dual channel high electron mobility field effect transistor

Abstract

A multi-terminal Group III-V semiconductor high electron mobility field effect transistor comprised of a sandwich of molecular beam epitaxially grown layers and including two high mobility charge flow channels in respective two dimensional electron gas regions implemented, for example, by at least one doped layer of aluminum gallium arsenide adjacent an undoped gallium arsenide layer separated by a heterojunction. A pair of opposing two dimensional electron gas (2DEG) regions are generated in the layer of undoped gallium arsenide by the bending of the energy levels of the semiconductor materials. Charge flow occurs in a unidirectional fashion from one channel to the other in the common undoped gallium arsenide layer under the control of an electric field applied transversely through the structure by means of a top gate electrode and a bottom field plate electrode. Alternatively, the source voltage can be increased until the requisite amount of energy has been provided for the electrons to become 'hot' enough to transfer from one channel to the other, in which case a lower biasing contact is not required. Relatively high signal isolation is inherently provided thereby between a pair of output terminals or signal ports. The device, moreover, is operable as a high speed signal coupler, amplifier, mixer as well as a photoelectric detector/amplifier.