Detection of nanopipes in GaN films by localized avalanche breakdown usingNaOH electrolyte

Nanopipes in high-quality GaN films grown by metalorganic chemical vapor de position (MOCVD) on a sapphire substrate were investigated by generating ho llow etch pits. Hollow etch pits were formed on the surface of GaN films by localized avalanche breakdown using NaOH electrolyte. Using scanning elect ron microscopy (SEM) and atomic force microscopy (AFM), the relationship be tween hollow etch pits and crystalline defects in GaN films was investigate d. It was found that hollow etch pits were formed at the nanopipes and elec trical discharge occurred through these nanopipes at high electric fields, resulting in localized avalanche breakdown. Defect etching by localized ava lanche breakdown was found to be a simple method to detect nanopipes in GaN films.