1.7-kV vertical GaN p-n diode with triple-zone graded junction termination extension formed by ion-implantation

Edge termination has emerged as an important area in the design and realization of vertical GaN power electronic devices. While the material properties of GaN are promising for high-performance devices, in practice the breakdown voltage can be compromised by inadequate edge termination (ET). While solutions in other materials (e.g. Si, SiC) are well-known, these are challenging to implement in GaN due to inherent difficulties in p-type doping GaN. In this work, we report a etch-free triple-zone graded junction termination extension (JTE) for vertical GaN diodes formed by Nitrogen ion implantation. The triple-zone design offers lower peak fields for effective field control. In addition, the proposed triple-zone JTE is beneficial for increasing the fabrication process window and allowing for more variability in epitaxial wafer growth in terms of p-GaN doping and thickness while maintaining high breakdown voltage. The fabricated GaN p-n diodes with triple-zone JTE obtain a maximum breakdown voltage of 1.73 kV with specific on-resistance Ron of 0.4 mΩcm2. Temperature-dependent reverse characteristics show that the devices have a positive temperature coefficient of the breakdown voltage indicating an avalanche breakdown mechanism. These results suggest that vertical GaN p–n diodes with N-implanted triple-zone JTE are promising for power applications