Comparative Study of AlGaN/AlN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors with Ni/Au Gate Electrode

In this article, Al0.28Ga0.72N/AlN/GaN metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs) with Ni/Au gate metal electrode are demonstrated. NiO or Al2O3 gate oxide layer is employed as a gate dielectric layer effectively decreases the gate leakage current, enhances drain current density, and transconductance, simultaneously. As compared with the metal-semiconductor (MS) Schottky-gate device, excellent characteristics are achieved for the MOS-HEMT with NiO (Al2O3) gate oxide layer, which include maximum drain-to-source saturation current density of 626.5 (692.0) mA mm-1, maximum transconductance of 87.6 (94.2) mS mm-1, gate-to-drain leakage current of 1.47 10-7 (8.21 10-11) mA mm-1, threshold voltage of -3.48 (-3.45) V, gate voltage swing of 2.88 (3.08) V, respectively. Experimentally, the MOS-HEMT with an Al2O3 gate oxide layer shows good potential for signal amplification and circuit applications.