Interplay of defects, microstructures, and surface stoichiometry during plasma processing of GaN

Abstract

We have investigated optical properties of dry eleched GaN using photoluminescence (PL) and micro-Raman scattering. The stoichiometry of the dry etched surface has been analyzed by x-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) technique has been employed to investigate the microstructures resulting from dry processing. The damage introduced by inductively coupled plasma etching has been assessed and improvement of the luminescence properties is observed during post etch annealing. The observed changes in the Raman spectra of plasma etched Si- and Mg- doped GaN can be associated with electronic and vibronic scattering mechanisms of defects.