Laser annealing of refractory OHMIC contracts to GaAs

Laser annealing has been successfully applied in producing low resistance ohmic contact to GaAs using refractory metallizations. These alloy systems include TiW, Ta, Mo, and Ni deposited on epitaxial Ge layers grown on (100) n type GaAs substrates. In some cases an N- layer obtained by ion implantation was present at the GaAs surface. Ohmic contact resistances of 1-5 X .0000001 omega-sq cm have been produced by laser annealing. These values compare favorably with the results obtained by thermal annealing. The refractory ohmic contacts reported here are intended to improve the reliability of devices operated under high-temperature and/or high-power conditions.