The Optimization of NiO Doping, Thickness, and Extension in kV-Class NiO/Ga2O3 Vertical Rectifiers

Ga2O3 heterojunction rectifiers have emerged as a novel candidate for various power conversion applications by using NiO as the solution on the p-type side. In this work, the optimized design of high-breakdown (1-7 kV), vertical geometry NiO/Ga2O3 rectifiers was examined using the Silvaco TCAD simulator to determine the electric field distribution for different NiO parameters. The doping concentration (10(17)-10(19) cm(-3)), thickness (10-70 nm) of the guard ring, and its extension beyond the anode (0-30 & mu;m) are all important in determining where the device breakdown occurs. Spatially, this can vary from the edge of the bilayer NiO extension to directly at the periphery of the top contact, consistent with experimental results. This transition phenomenon is proven to be correlated with the depletion effect by monitoring the depletion width when ramping up the bias and the doping concentration. The breakdown voltage was also calculated as a function of NiO top and bottom layer thicknesses and the doping concentration under different critical breakdown fields, where the latter is determined by the material quality of the drift layer.

Automated summary

Ga2O3 heterojunction rectifiers with NiO as the solution on the p-type side have become a novel candidate for power conversion applications. In this study, the optimized design of high-breakdown NiO/Ga2O3 rectifiers was examined using the Silvaco TCAD simulator to determine the electric field distribution. The doping concentration, guard ring thickness, and extension beyond the anode were all important factors in determining the breakdown location. The transition phenomenon from the edge of the NiO extension to the top contact periphery was found to be correlated with the depletion effect.