GaAs MESFET fabrication without using photoresist

MBE-grown MESFET wafers were patterned with a novel resistless approach and InAs was selectively grown in the source and drain regions. Photoresist and the associated process steps and chemicals were eliminated by utilizing gallium oxide as the masking material. Metallization for the source, drain and self aligned gate was carried out in one step, also without using any photoresist. Device structures with gate lengths ranging from submicron to 10 μm were fabricated.