Boron-Implanted Termination Structures for Vertical GaN Power Devices with Highly Enhanced Breakdown Voltage

Abstract

We propose a new edge termination technique for high-voltage vertical GaN power devices using boron-ion implantation into a p-GaN epitaxial layer. The boron-implanted layer after annealing at 800°C results in a half-conductive p-type layer that is applicable to junction termination extension (JTE). The maximum breakdown voltage of 1400 V was near an ideal value for the donor concentration in the drift layer. High avalanche current immunity was observed for the optimal structure. In wafer-scale fabrication of the p-n diodes on a 4-inch free-standing GaN substrate, good reverse characteristics are observed across the wafer. The proposed JTE technique has high potential for wafer-scale fabrication of robust and highly efficient vertical GaN devices.