Morphological instabilities during homoepitaxy on vicinal GaAs(110) surfaces
Growth of GaAs by molecular beam epitaxy on (110) substrates vicinal to (111)A has been systematically studied by atomic force and Nomarski microscopy at different As/Ga flux ratios, substrate temperatures and growth rates. Depending on the growth conditions, a striking variety of morphological instabilities have been found that range from step bunching in the Ga-supply limited regime to creation of long-range, well-ordered patterns of three-dimensional pyramidal features on the surface under As-deficient conditions. We discuss the microscopic origin of the morphological instabilities and self-organization of the surface features in terms of growth modes, relative adatom populations and step-attachment probabilities.
morphological instabilities homoepitaxy molecular beam epitaxy