1 kV/2.7 MV/cm GaN quasi-vertical Schottky barrier diode with self-aligned mesa-field plate composite termination

This work demonstrates an innovative self-aligned mesa-field plate (SMFP) termination for fabricating GaN quasi-vertical Schottky barrier diodes with enhanced breakdown performance. By depositing a field plate on the sidewall of the self-aligned mesa (SM), the SMFP enables a more uniform peripheral electric field within GaN by reducing the surface field effect, thereby mitigating premature breakdown induced by the combined effects of electric field crowding and etching damage. As a result, the breakdown voltage of the optimized device increases from 215 V (without edge termination) and 740 V (SM) to 1 kV. The parallel-plane junction electric field correspondingly rises from 1 and 2.1 to 2.7 MV/cm, reaching 82% of the GaN critical electric field. Furthermore, the breakdown failure site transitions from the anode periphery to the device interior, advancing breakdown performance toward the voltage-withstanding limit of the epitaxial layer. These findings facilitate the advancement of GaN high-voltage power devices.