Passivating gallium arsenide semiconductor device - using semi-insulating gallium arsenide deposits between mesas of active gallium arsenide

摘要

Semi-conductor device is passivated by (a) erosion of a plate, consisting of a monocrystalline GaAs substrate carrying several monocrystalline layers of GaAs and a layer of a masking material, as far as the plate, so as to leave a number of mesa components having in common at least part of the substrate. Process further comprises (b) a supply of semi-insulating monocrystalline GaAs by epitoxy on those parts eroded, so as to fill the spaces between the mesa components and (c) removal of the masking material. The masking material is SiO2 or Si3N4. The GaAs supplied is made semi-insulating by doping with O2 and Cr during deposition, by means of vapour of CrO2Cl2 carried by hydrogen, or by Cr dissolved in liq. Ga. Used for the mfr. of a Gunn diode or an avalanche diode. Process avoids the need for prior masking, localised polishing or local etching using a suitable mask of a flat surfaced coated substrate to remove the passivating layer from the access electrodes.