Al_2O_3 Insulated-Gate Structure for AlGaN/GaN Heterostructure Field Effect Transistors Having Thin AlGaN Barrier Layers

摘要

An Al_2O_3 insulated-gate (IG) structure was utilized for controlling the surface potential and suppressing the gate leakage in Al_(0.2)Ga_(0.8)N/GaN heterostructure field effect transistors (HFETs) having thin AlGaN barrier layers (less than 10 nm). In comparison with the Schottky-gate devices, the Al_2O_3 IG device showed successful gate control of drain current up to V_(GS) = +4 V without leakage problems. The threshold voltage in the Al_2O_3 IG HFET was about -0.3 V, resulting in the quasi-normally-off mode operation.