Effect of AlAs Buffer Layers on Epitaxial Growth of GaAs on Si (100)

Dislocation density and full width at half maximum (FWHM) of X-ray diffraction of GaAs grown on Si substrates are reduced with thin AlAs buffer layers grown by migration-enhanced epitaxy. Reflection high-energy electron diffraction (RHEED) and Auger measurements indicate that this is attributable to the layerlike growth of AlAs. There is an optimum AlAs buffer layer thickness. The minimum etch pit density and the minimum FWHM of X-ray diffraction are obtained at the thickness of 35 monolayers of AlAs. They are 6×10 6 cm -2 and 183 arcsec, respectively.