Abstract: A method of fabricating semiconductor devices on semi-insulating GaAs substrates is provided. Pre-etched holes in the substrate are covered with a dielectric which is etched to expose the substrate only at the bottom of the holes. Epitaxial growth of active GaAs in the holes may then proceed with a single crystallographic orientation. The dielectric covering the sidewalls of the holes prevents unwanted random growth and poor surface morphology of the active area.

Abstract: A method of fabricating gallium arsenide circuits or devices in which source and drain contact areas are deposited using vapor phase epitaxy techniques through holes in a refractory mask. Selected areas of a refractory mask are etched away to expose a region of active gallium arsenide material in which holes are formed by a chemical or plasma etch. These holes are then filled with highly doped vapor phase epitaxially grown gallium arsenide to provide drain and source contact regions. In further steps additional regions of the refractory mask are etched away to define gate regions. Metallization and lift-off may then occur in a single step to provide contacts to gate, drain and source regions and a planar surface for further device processing.