A New JTE Technique for Vertical GaN Power Devices by Conductivity Control Using Boron Implantation into p-Type Layer

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). Fabricated vertical p-n diodes with the JTE layers show substantial increase in breakdown voltage (BV) via tuning of the boron concentration. The JTE length dependence of the BV and photoemission location demonstrate that the electric field relaxation near the edge can be controlled by the boron implantation conditions. High avalanche current immunity and positive temperature dependence of the BV are observed for the optimal structure. The maximum BV of 1400 V is near an ideal value for the donor concentration in the drift layer. The proposed JTE technique can be a strong candidate for robust power devices.