DepletionmodeHEMTwithrefractorymetalsilicideWSigatehasbeende-signedandfabricated.Epicated.Epitaxialmodulationdopingmaterialsweregrownbyahome-madeMBEsystem.Thegatelengthandwidthforlownoisedepletiondeviceswere1.2~1.5μmand2×160μmrespectively.Theelectronmobilityofthefabricateddevicesistypically6080cm^2/V·sat300Kand68000cm^2/V·sat77K.Thesheetelectronconcentrationnsis9×10^11cm^-2,Thesource-draincontactswithAuGeNi/Auwerefabricatedusingevaporatingandlift-offtechnique.tofurtherreducethecontactresistance,thewaferalloyedat520℃for3mininthehydrogen(H2)gas.SchottkygatewasformedusingWSi.Thetranseon-ductanceofthedepletionmodedeviceis110~130mS/mmatroomtemperature,Thede-vicescanbeappliedincommunicationsatelliteatmicrowavefreqencyof3.83GHzandradarreceiverat1.5GHz.Itsnoisefigureisabout2~3dB.