High-temperature processing of GaN: The influence of the annealing ambient on strain in GaN

Abstract

Using micro-Raman scattering we have investigated the influence of the annealing ambient on the high-temperature processing of GaN. Compressive strain is found in GaN layers after high-temperature processing in oxygen-containing atmospheres. This strain is significantly enhanced by the addition of water vapor to the annealing ambient, suggesting the enhanced inclusion of oxygen into GaN. Characteristic photoluminescence lines appear at 3.355 and 3.406 eV after annealing in oxygen in the presence of water vapor. No strain is introduced by high-temperature processing in nitrogen ambient, even at temperatures close to the thermal decomposition temperature and in the presence of water vapor.