Correlation between Surface Morphology and Electrical Properties of GaAs Grown by Metalorganic Chemical Vapor Deposition

Surface morphology, including growth pyramids and rough surface, formed on MOCVD grown GaAs epitaxial layers has been investigated for different ratios of As to Ga atoms during growth. Such a morphology is correlated with the electrical property of the film. More specifically, rough surface textures together with p-type conductivity of the undoped sample result simultaneously for smaller As to Ga ratios. The effect of the As to Ga ratio on surface morphology and conductivity-type conversion is different for different orientations of substrates. This fact and the formation of the growth pyramids are explained on the basis of a local deficiency of As at the growth surface.