A Simple Gate-Dielectric Fabrication Process for AlGaN/GaN Metal–Oxide–Semiconductor High-Electron-Mobility Transistors

This letter reports a simple processing method for fabricating metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) by using hydrogen peroxide (H₂O₂) oxidation technique. Aluminum oxide (AlO_x) was formed on the surface of the AlGaN barrier as the gate dielectric of the MOS-gate structure. By using the capacitance-voltage measurement, the dielectric constant (κ) of AlO_x was determined to be 9.2. The present MOS-HEMT has demonstrated enhanced saturation drain current density at V_GS = 0 V (I_DSS0) of 552.3 mA/mm, maximum extrinsic transconductance (g_{m, max}) of 136 mS/mm, wide gate voltage swing of 2.9 V, and two-terminal gate-drain breakdown/turn-on voltages (BV_GD/V_on) of -132.2/1.82 V.