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.