Low-temperature annealed contacts to very thin GaAs epilayers

Abstract
A low-temperature annealing process has been developed for the fabrication of low resistivity ohmic contacts to very thin (<0.2 μm) n+ GaAs epilayers. It is shown that by altering the relative amounts of Ni in the commonly used AuGe/Ni/Au contact system, the anneal temperature can be reduced from the standard 420–450 °C to 320 °C or less without deterioration in specific contact resistance. The specific contact resistances were evaluated using the modified transmission line model.