Diffusion and incorporation: shape evolution during overgrowth on structured substrates

We simulate the surface shapes during homoepitaxial overgrowth of patterned GaAs substrates in the sector (0 0 1)(111)A. The model for the shape evolu tion is based on a diffusion equation in which the orientation-dependent pa rameters vary according to a simple model of the surface free energy of the zineblende crystal structure. Metastable pseudofacets its well as the init ial shape of the step are demonstrated to play a major role in the evolutio n of the surface during overgrowth. (C) 2001 Elsevier Science B.V. All righ ts reserved.