Effect of germanium cap layer on indium ohmic contacts for n-type GaAs

Ohmic contacts from Ge/In were successfully fabricated. Thin film of In and Ge were sequentially deposited onto a clean n-type GaAs surface as contact and followed by annealing at various temperatures up to 800 C in nitrogen ambient. Ge acted as a capping layer and promoted formation of InAs. Linear TLM and contact end resistance measurement were employed to characterize the specific contact resistance, /spl rho//sub c/. Lowest /spl rho//sub c/ obtained with Ge/In contact was 3.38 10/sup -3/ /spl Omega/cm/sup 2/. Due to unintentional oxidation reduction in specific contact resistance by Ge was not observed.