An interdigitated GaN MIS-HEMT/SBD normally-off power switching device with low ON-resistance and low reverse conduction loss

A three-terminal normally-off GaN switching device with highly desired low-loss reverse conduction capability was demonstrated using a chip-area-efficient device structure design. This device features interdigitated normally-off MIS-HEMT and high-performance embedded anti-parallel Schottky barrier diode (SBD) along the gate width direction, with the transistor and diode sections sharing common ohmic contacts and access regions. The device with a MIS-HEMT/SBD width ratio of 2:1 exhibits a threshold voltage (Vth) of ∼1.8 V, a forward ON-resistance (RON) of 12.1 Q-mm, an off-state leakage current of 18 nA/mm (VDS = 200 V) and an off-state breakdown voltage (BV) of 698 V. The reverse conduction turn-on voltage (VR-T) is 0.6 V even at a negative gate bias.