Effects of alloy ambient on PdGe contacts on n-type GaAs

A high concentration of hydrogen in the alloy ambient slows the formation of PdGe contacts and increases the resistance of the PdGe to GaAs etchants. The effects of alloy ambient on alloy formation, specific contact resistance, and chemical reactivity of PdGe contacts on n-type GaAs have been studied. A very low specific contact resistance of <1×10−7 Ω cm2 has been achieved on GaAs with PdGe contacts alloyed at 300 °C for 15 min in a hydrogen ambient. These results indicate that PdGe may be a desirable contact for GaAs-based transistors.