Normally-OFF Al2O3/AlGaN/GaN MOS-HEMT on 8 in. Si with Low Leakage Current and High Breakdown Voltage (825 V)

We report recessed-gate Al2O3/AlGaN/GaN normally-OFF metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) on 8 in. Si. The MOS-HEMTs showed a maximum drain current of 300 mA/mm with a high threshold voltage of +2.4 V. The quite low subthreshold leakage current (∼10−8 mA/mm) yielded an excellent ON/OFF current ratio (9 × 108) with a small, stable subthreshold slope of 74 mV/dec. An atomic-layer-deposited Al2O3 layer effectively passivates, as no significant drain current dispersions were observed. A high OFF-state breakdown voltage of 825 V was achieved for a device with a gate-to-drain distance of 20 µm at a gate bias of 0 V.