CMOS-compatible ehancement-mode GaN-on-Si MOS-HEMT with high breakdown voltage (930V) using thermal oxidation and TMAH wet etching

In this paper, we report for the first time, an enhancement-mode (E-mode) Al₂O₃/GaN metal-oxide-semiconductor high-electron-mobility-transistor (MOS-HEMT) using CMOS-compatible techniques including gate region local thermal oxidation and organic alkaline solution (TMAH) wet etching. The fabricated MOS-HEMT exhibits a high positive threshold voltage of +2.5 V, indicating complete pinch-off of the 2 dimensional electron gas (2DEG) channel. Maximum drain current of 250 mA/mm and an off-state breakdown voltage up to 930 V at a 0 V gate bias are observed for the fabricated device of L_G = 2.0 μm and L_GD = 14 μm, manifesting a low cost, highly repeatable CMOS compatible fabrication method of normally-off GaN-on-Si devices for power electronics applications.