AlSb/InAs HEMTs with a TiW/Au gate metalization

We report on the fabrication and characteristics of AlSb/InAs HEMTs with a TiW/Au gate metalization. Prior to the metal evaporation, the usual oxygen plasma surface pretreatment was adjusted to minimize damage. These HEMTs exhibit decreased gate leakage current in the low drain bias region and similar microwave performance compared to previous HEMTs fabricated from the same material with a Cr/Au gate metal. The HEMTs were found to be thermally stable up to 180/spl deg/C when heat treated in a H/sub 2//N/sub 2/ ambient. TiW/Au diode test structures fabricated on similar HEMT material were thermally stable up to 270/spl deg/C.