Window etching through indium-gallium phosphide layer, especially emitter region of heterojunction bipolar transistor, e.g. for a high power microwave amplifier, involves using a silicon nitride mask

摘要

Window etching through an InGaP layer (20) is carried out using a silicon nitride layer (32) as mask. A window is etched through a selected region of an InGaP layer (20) by forming a silicon nitride layer (32) on the InGaP layer (20), forming a window through a selected silicon nitride layer region and removing the exposed InGaP layer region. Independent claims are also included for the following: (i) a heterojunction transistor production process including the above etching operation; (ii) a heterojunction bipolar transistor production process including the above etching operation; and (iii) a heterojunction bipolar transistor produced by the above process.