Extremely low-resistance nonalloyed ohmic contacts have been formed on p-type Ge grown on GaAs by molecular beam epitaxy as part of a research effort into GaAs/Ge heterojunction devices. Using evaporated Ti/Al metallisation, specific contact resistances well below 1*10/sup -8/ Omega cm/sup 2/ were achieved for heavily doped Ge (p>1*10/sup 19/ cm/sup -3/). The investigated Ge layers were grown as the base region of AlGaAs/Ge/GaAs HBTs. The influence of the low base resistance on the high-frequency performance of HBTs was studied by simulations.<<ETX>>