Al2O3 Insulated-Gate Structure for AlGaN/GaN Heterostructure Field Effect Transistors Having Thin AlGaN Barrier Layers

摘要

An Al2O3 insulated-gate (IG) structure was utilized for controlling the surface potential and suppressing the gateleakage in Al0.2Ga0.8N/GaN heterostructure field effect transistors (HFETs) having thin AlGaN barrier layers (less than 10 nm). In comparison with Schottky-gate devices, the Al2O3 IG device showed successful gate control of drain current up to VGS= +4 V without leakage problems. The threshold voltage in the Al2O3 IG HFET was about -0.3 V, resulting in the quasi-normally-off mode operation.