Enhancing Breakdown Voltage of a Ga2O3 Schottky Barrier Diode with Small-Angle Beveled and High-k Oxide Field Plate

Abstract

To increase their breakdown voltage, Ga2O3 Schottky barrier diodes (SBDs) with a beveled field plate were designed based on TCAD platform simulations. The small-angle beveled field plate can effectively alleviate the electric field concentration effect. The breakdown voltage of Ga2O3 SBDs can reach 1217 V with the SiO2 dielectric and a small-angle (1°) beveled field plate. However, the breakdown mechanism is the early breakdown of the dielectric layer. TO further increase the breakdown voltage, the replacement of SiO2 with a high-k dielectric (Al2O3 and HfO2) can transfer the breakdown location into the Ga2O3 drift layer. By combining the beveled small-angle design and the high-k dielectric, the device demonstrates a Baliga’s figure of merit of 2.94 GW cm−2 and breakdown voltage of 3108 V.