Demonstration of 1.27 kV Etch-Then-Regrow GaN p-n Junctions with Low Leakage for GaN Power Electronics

This letter reports high performance GaN p-n junctions with regrown p-GaN by metalorganic chemical vapor deposition (MOCVD) on dry-etched surfaces. The breakdown voltage reaches 1.27 kV and the differential on-resistance is 0.8 mΩ c cm². The effects of etching powers and surface treatments on the reverse leakage characteristics of the regrown p-n junctions have been investigated. It's found that lowering the etching power and damage is very effective to reduce the leakage currents and increase the breakdown voltages. Further analysis reveals that the charge concentration at the regrowth interface plays a critical role in the performance of the regrown samples. To avoid sacrificing the etching rate by using only low power etching, a multiple-RF-power etching recipe was developed with gradually decreased etching power. This work has demonstrated a practical and viable method to realize high performance regrown p-n junctions for various advanced GaN power electronics.