Design and Fabrication of Ion-Implanted Moat Etch Termination Resulting in 0.7 mΩ·cm2/1500 V GaN Diodes

The design space of ion-implanted moat etch termination in GaN p-n diodes is discussed in this study. Based on experimental data, the design window for ion-implanted moat etch termination has been carefully studied and optimized for vertical GaN p-n diodes grown on bulk GaN substrates. A high-performance diode with a breakdown voltage of 1500 V and a low specific on-state resistance of 0.7 $\text{m}\Omega \cdot $ cm2 is demonstrated using the optimized edge termination based on moat etch and Mg ion implantation. The p-n diode shows a device figure-of-merit of 3.2 GW/cm2. By using the proposed ion-implanted moat etch termination, GaN diodes with three different drift region designs approach the avalanche breakdown electric field, which indicates the efficacy of the proposed edge termination design and method.