WSix gate pseudomorphic GaInP/In0.2Ga0.8As HEMTs were fabricated, and evaluated for the purposes of high temperature operations. Based on the high thermal stability of WSi, gates, no significant change in device characteristics was observed for temperatures up to 200 degrees C. Functional devices can still be obtained at 300 degrees C. Comparing with the other gate materials, for example Ti/Au or Al gates, WSix demonstrates the advantages of this highly thermal stable property.
