Device performance at elevated temperatures up to 200/spl deg/C in AlGaN/GaN insulated gate heterostructure field effect transistors with ultra-thin Al/sub 2/O/sub 3//Si/sub 3/N/sub 4/ bilayer

We have investigated the device performance of MIS-HFET with ultra-thin Al/sub 2/O/sub 3//Si/sub 3/N/sub 4/(1 nm/0.5 nm) at elevated temperatures up to 200/spl deg/C. The device exhibits very low gate current leakage under reverse conduction and high transconductance at both RT and 200/spl deg/C due to the employment of ultra-thin bilayer with large dielectric constants and large conduction band offset between Al/sub 2/O/sub 3/ and nitrides. No anomalous characteristics were observed at high temperature may due to the excellent interfacial quality between AlGaN and Si/sub 3/N/sub 4/. The works in this paper demonstrate that Al/sub 2/O/sub 3//Si/sub 3/N/sub 4/ bilayer insulator is a superior candidate for nitrides-base MIS-HFET devices operated at high temperatures.