A method for controlling the spacing between the emitter mesa and the base ohmic metal of a heterojunction bipolar transistor (HBT) to obtain a relatively high gain (.beta.) with a low-parasitic base resistance. In a first method, after the emitter, base and collector layers are epitaxially grown...http://www.google.com.au/patents/US5804487?utm_source=gb-gplus-sharePatent US5804487 - Method of fabricating high .beta.HBT devices
