Degenerately doped (n=5×1020cm−3) InN grown by metalorganic molecular beam epitaxy is used for emitter Ohmic contacts on GaAs/AlGaAs heterojunction bipolar transistors (HBTs). Both abrupt InN/GaAs and graded GaAs/InGaAs/InN contact structures were investigated. Although, the contact resistivity of nonalloyed Ti/Pt/Au on InN was achieved as low as 1.8×10−7&OHgr; cm2, formation of a thin GaN layer at the interface of the InN/GaAs system limits nonalloyed TiPtAu metallization to contact resistivities of 10−4&OHgr; cm2. Whereas the graded structure, GaAs/InGaAs/InN material, system produces values of 5×10−7&OHgr; cm2which resulted in the formation of conductive InN from nitridation of InAs instead of the GaN layer for the InN/GaAs system. The InN‐based emitter contacts have superior surface morphologies to the more conventional InAs layers. The C‐doped base (p=7×1019cm−3) HBTs utilizing 2×5 &mgr;m2InN‐based emitter contacts is demonstrated with dc gains of 35. ©1995 American Institute of Physics.