Investigation of Substrate Orientation Dependence for the Growth of GaN on GaAs (111)A and (111)B Surfaces by Metalorganic Hydrogen Chloride Vapor-Phase Epitaxy

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Abstract
It was found that a 50-nm-thick GaN buffer layer grown by metalorganic hydrogen chloride vapor-phase epitaxy (MOHVPE) at 550°C on a GaAs (111)A surface did not deteriorate even after subsequent heating in an NH3 ambient up to 1000°C, whereas numerous pinholes were formed when the buffer layer was grown on a GaAs (111)B surface. In addition, serious arsenic (As) desorption from the GaAs substrate occurred through the pinholes. A single crystal hexagonal GaN layer with a mirror-like surface can be grown at 1000°C on the 50-nm-thick GaN buffer layer grown at 550°C on the GaAs (111)A surface, as confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The full-width at half maximum (FWHM) of the ω mode scan for the GaN (0002) plane was 1450 arcsec. Photoluminescence (PL) measurement showed a sharp band-edge emission at 363.1 nm with a FWHM of 96 meV at room temperature.