Al0.25Ga0.75N/GaN enhancement-mode MOS high-electron-mobility transistors with Al2O3 dielectric obtained by ozone water oxidization method

Abstract

Al0.25Ga0.75N/GaN enhancement-mode (E-mode) metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) obtained by the ozone water oxidization method are investigated in this work. Decreased gate leakage and reduced channel depletion are obtained by forming the Al2O3 dielectric layer of the MOS gate structure by a cost-effective oxidization method. Pulse current–voltage (I–V), low-frequency noise, and Hooge coefficient measurements are compared to verify the interface quality improved by the oxide passivation effect. In comparison, a conventional Schottky-gate HEMT device is also fabricated on the same epitaxial sample. Enhanced device gain, current drive density, breakdown, on/off current ratio, and high-temperature stability up to 450 K are also investigated in this work.