First Demonstration of RESURF and Superjunction ß- Ga2O3 MOSFETs with p-NiO/n- Ga2O3 Junctions

We for the first time demonstrate the conceptual superjunction (SJ) and reduced-surface-field (RESURF) ß- Ga<inf>2</inf>O<inf>3</inf> MOSFETs. The electric field engineering is implemented by the alternatively arranged p-NiO/n-Ga<inf>2</inf>O<inf>3</inf> lateral SJ pillars and RESURF structures in the drift region through the selective epitaxy of p-NiO. High interface quality of the NiO/ Ga<inf>2</inf>O<inf>3</inf> heterojunction is experimentally verified by a low leakage current of <10⁻⁶ A up to 1500 V without breakdown. Both SJ and RESURF ß- Ga<inf>2</inf>O<inf>3</inf> MOSFETs exhibit significantly improved breakdown voltage (V<inf>br</inf>) as compared to the control devices without p-NiO. In particular, benefiting from the charge balance, the fabricated SJ-MOSFET (L<inf>GD</inf> = 15.5 µm and L<inf>SD</inf>= 20 µm) achieves a high V<inf>br</inf> of 1362 V in air, and yields a power figure-of-merit (PFOM) of 39 MW/cm², which are 2.42 and 4.86 times higher than the control transistor. Our results proved that the SJ transistor utilizing p-NiO/n-Ga<inf>2</inf>O<inf>3</inf> junctions is a promising technological strategy to fulfill the potential of Ga<inf>2</inf>O<inf>3</inf> for high power applications.