High Drain Current Density E-Mode Al₂ O₃/AlGaN/GaN MOS-HEMT on Si With Enhanced Power Device Figure-of-Merit (4× 10⁸~ V²Ω⁻¹ cm⁻²)

In this paper, we report on the enhancement-mode (E-mode) Al2O3/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMTs) on Si. The E-mode operation is due to the negative charges in the atomic layer deposited Al2O3layer. The unrecessed E-mode MOS-HEMTs exhibit high drain current density with a low specific ON-state resistance (RON,sp) of 0.7 mΩ·cm2. A low gate leakage current showed enhancements in the subthreshold characteristics such as ION/IOFF ratio ~108and subthreshold slope of 75 mV/decade. This E-mode device showed good retention characteristics of threshold voltage upto 105s. Furthermore, the E-mode MOS-HEMT exhibits an OFF-state breakdown voltage of 532 V for short gate-to-drain distance (Lgd=4 μm) that records a high power device figure of merit (FOM=BV2/RON,sp) value of 4×108V2Ω-1cm-2.