AlGaN/GaN MOS-HEMTs with ZnO gate insulator and chlorine surface treatment

AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) were fabricated with ZnO gate insulator and chlorine surface treatment. It is revealed that the chlorine treatment reduced the gate lag phenomenon and enhanced the device performance. The gate leakage current was also reduced about one order of magnitude in comparison to the conventional one. The chlorine-treated MOS-HEMTs exhibited a saturation drain-source current of 0.85 A/mm, a peak extrinsic transconductance of 207 mS/mm, and an off-state breakdown voltage larger than 100V. This significant improvement was owing to the reduction in surface state density, which was resulted from the decrease of Ga dangling bonds and the passivation of N vacancies on the AlGaN surface.