p-Type AuMn ohmic contact on GaAs: integration in a HBT processing technology

The influence of the p-type doping level in GaAs on the AuMn specific contact resistivity has been investigated, showing that AuMn could be used as an ohmic contact on epitaxial layers with a very large range of doping levels. The integration of this contact in the processing technology of heterojunction bipolar integrated circuits has been analysed, showing the influence of the processing steps preceding the contact evaporation. The contact resistivity has been found to be very sensitive to defects created by ion beam etching, making necessary a light chemical etch before depositing the contact.