Pd/Ge/Ti/Pt and Pd/Si/Ti/Pt ohmic contacts to n-type InGaAs were investigated for applications to AlGaAs/GaAs HBT emitter ohmic contacts. In both ohmic contacts, low-resistance and non-spiking planar interfaces were obtained by rapid thermal annealing. RF performance of the AlGaAs/GaAs HBT was also examined by employing these contact systems.