Raman Study of the High Pressure Oxidation of GaAs.
26 July 1988
Recent studies of oxide phases grown on GaAs have led to the suggestion that the observation of elemental arsenic in these films is dependent on the substrate doping. This hypothesis is at variance with the condensed phase portion of the Ga-As- O equilibrium diagram which predicts that elemental arsenic is a stable interfacial phase independent of substrate doping. Oxide films grown on (100) GaAs under both high and low O sub 2 pressures have been examined using Raman scattering in order to determine whether the formation of elemental arsenic inclusions is influenced by either the substrate doping type or the oxygen chemical potential. Elemental arsenic was unambiguously observed in all oxidized films independent of variations in the latter parameters. Crucial elements of the Ga-As-O equilibrium diagram determined by C. D. Thurmond et al. are reconfirmed.