Impact of damage-free wet etching process on fabrication of high breakdown voltage GaN p-n junction diodes

Pulsed photo-electrochemical (PEC) etching was performed to fabricate mesa-structure vertical GaN p-n junction diodes without process damages which are inevitable in the conventional dry etching process. The damage-free etched surface was confirmed by photoluminescence and cathode luminescence measurements. The most beneficial property of the GaN p-n junction diodes fabricated by PEC etching was the much reduced variation in their breakdown voltages (3.83-3.88 kV) compared with those fabricated by conventional dry etching (3.36-3.81 kV). These results indicate the excellent potential of PEC etching in the fabrication of GaN power devices. (C) 2019 The Japan Society of Applied Physics