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

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.