Germanium-palladium ohmic contacts to n-type GaAs
Ohmic contacts to n-GaAs (Si doped at 2.7*1015 cm-3 and 4.5*1018 cm-3) have been formed using a Ge/Pd/GaAs metallisation and annealing for short times yielding specific contact resistivities ( rho c) of 2.27*10-4 Omega cm2 for low-doped epilayers and 1.25*10-6 Omega cm2 for high-doped epilayers. The resulting contacts display a smooth surface and sidewalls. Contact has also been made to two modulation doped structures with specific contact resistivities of 4.22*10-4 and 1.09*10-4 Omega cm2 using the same metal system.