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

Abstract

We for the first time demonstrate the conceptual superjunction (SJ) and reduced-surface-field (RESURF) ß- Ga 2 O 3 MOSFETs. The electric field engineering is implemented by the alternatively arranged p-NiO/n-Ga 2 O 3 lateral SJ pillars and RESURF structures in the drift region through the selective epitaxy of p-NiO. High interface quality of the NiO/ Ga 2 O 3 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 2 O 3 MOSFETs exhibit significantly improved breakdown voltage (V br ) as compared to the control devices without p-NiO. In particular, benefiting from the charge balance, the fabricated SJ-MOSFET (L GD = 15.5 µm and L SD = 20 µm) achieves a high V br of 1362 V in air, and yields a power figure-of-merit (PFOM) of 39 MW/cm ² , 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 2 O 3 junctions is a promising technological strategy to fulfill the potential of Ga 2 O 3 for high power applications.