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 (H
₂
O
₂
) 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.