Demonstration of 4.7 kV breakdown voltage in NiO/β-Ga2O3 vertical rectifiers

Vertical heterojunction NiO/beta n-Ga2O/n(+) Ga2O3 rectifiers employing NiO layer extension beyond the rectifying contact for edge termination exhibit breakdown voltages (V-B) up to 4.7kV with a power figure-of-merits, V-B(2)/R-ON of 2GW.cm(-2), where R-ON is the on-state resistance (11.3 m Omega cm(2)). Conventional rectifiers fabricated on the same wafers without NiO showed V-B values of 840V and a power figure-of-merit of 0.11GW cm(-2). Optimization of the design of the two-layer NiO doping and thickness and also the extension beyond the rectifying contact by TCAD showed that the peak electric field at the edge of the rectifying contact could be significantly reduced. The leakage current density before breakdown was 144mA/cm(2), the forward current density was 0.8kA/cm(2) at 12V, and the turn-on voltage was in the range of 2.2-2.4 V compared to 0.8V without NiO. Transmission electron microscopy showed sharp interfaces between NiO and epitaxial Ga2O3 and a small amount of disorder from the sputtering process. Published under an exclusive license by AIP Publishing.