High power gallium arsenide schottky barrier field effect transistor

Claim 1

In combination in a high-power microminiature gallium arsenide field-effect-transistor device, a gallium arsenide substrate having an epitaxial mesa formed thereon, multiple interleaved source, gate and drain electrodes formed on said mesa, each of said electrodes including a portion that extends beyond one edge or the opposite edge of the mesa and onto said substrate, a drain bus bar on said substrate adjacent said one edge of said mesa connecting together said drain electrodes, a gate bus bar, including cross-under fingers, on said substrate adjacent the opposite edge of said mesa connecting together said gate electrodes, insulating portions disposed on selected regions of said cross-under fingers, and a source bus bar on said substrate adjacent said opposite edge of said mesa extending over the insulating portions on said cross-under fingers to connect together said source electrodes, wherein said cross-under fingers are respectively deposited in convex-bottom channels formed in said substrate, each of said fingers comprising, in order of deposition, layers of germanium/gold, silver, gold and tungsten.