A new self-aligned AlGaAs/GaAs HBT with an InGaAs emitter cap layer is presented. This HBT has nonalloyed ohmic contacts to the emitter and base that are formed simultaneously and in a self-aligned manner. The low emitter contact resistance of 1.4×10-7 Ωcm2 and the high transconductance per unit area of 3.3 mS/μm2 demonstrate the effectiveness of this structure.