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

We for the first time demonstrate the conceptual superjunction (SJ) and reduced-surface-field (RESURF) beta-Ga2O3 MOSFETs. The electric field engineering is implemented by the alternatively arranged p-NiO/n-Ga2O3 lateral SJ pillars and RESURF structures in the drift region through the selective epitaxy of p-NiO. High interface quality of the NiO/Ga2O3 heterojunction is experimentally verified by a low leakage current of <10(-6) A up to 1500 V without breakdown. Both SJ and RESURF beta-Ga2O3 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 mu m and LSD= 20 mu m) 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-Ga2O3 junctions is a promising technological strategy to fulfill the potential of Ga2O3 for high power applications.