Device performance at elevated temperatures up to 200°C in AlGaN/GaN insulated gate heterostructure field effect transistors with ultra-thin Al2O3/Si3N4 bilayer

We have investigated the device performance of MIS-HFET with ultra-thin Al₂O₃/Si₃N₄(1 nm/0.5 nm) at elevated temperatures up to 200°C. The device exhibits very low gate current leakage under reverse conduction and high transconductance at both RT and 200°C due to the employment of ultra-thin bilayer with large dielectric constants and large conduction band offset between Al₂O₃ and nitrides. No anomalous characteristics were observed at high temperature may due to the excellent interfacial quality between AlGaN and Si₃N₄. The works in this paper demonstrate that Al₂O₃/Si₃N₄ bilayer insulator is a superior candidate for nitrides-base MIS-HFET devices operated at high temperatures.