Passivation of ohmic contacts to GaAs

A film of silicon dioxide was used to passivate Au-Ge-Ni metallization during the alloying cycle. Ohmic contacts prepared in this way had smooth surfaces, better edge definition, and more uniform electrical characteristics. Also the time-temperature alloying cycle for fabricating suitable contacts was significantly broadened. These improvements are most likely due to the prevention of arsenic loss during the alloying procedure.