Study of etching-induced damage in GaN by hard X-ray photoelectron spectroscopy

We carried out nondestructive measurements of the depth profile of etching-induced damage in p-type gallium nitride (p-GaN), in particular surface band bending, using Hard X-ray Photoelectron Spectroscopy (HAX-PES). HAX-PES at different take-off angles of photoelectrons made it clear that etching by inductively coupled plasma (ICP) introduced donor-like states in a surface layer of GaN. We were able to quantitatively analyze band bending and charge distribution in an etched p-GaN. The analysis results indicated the existence of deep donors with a concentration of 1-2 x 10(20) cm(-3) in a surface layer whose thickness increased with increasing a bias power of ICP. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim