Preparation of single phase gallium nitride from single crystal gallium arsenide

Abstract

An analysis has been conducted on the final products obtained in attempts to prepare single phase gallium nitride from single crystal gallium arsenide. When the intermediate oxide phase was nitrided in pure ammonia it was found that (i) the lowest temperature at which rate of conversion ofβ-Ga₂O₃ to GaN became significant was in the range 600 to 700°C, (ii) over the temperature range 700 to 1000°C GaN was found to be the only crystalline phase present, (iii) above 1100°Cβ-Ga₂O₃ was the main constituent. In comparison, when the oxide phase was nitrided in a 50% NH₃-50% N₂ atmosphere it was found that (i) the lowest temperature at which conversion to GaN occurred lay between 700 and 750°C, (ii) there was only a narrow range of temperatures, 750 to 870°C, in which the final products were found to contain GaN as the only crystalline phase, (iii) samples nitrided above 870°C exhibited both GaN andβ-Ga₂O₃ phases, the proportion ofβ-Ga₂O₃ increasing with increasing temperature.