Growth Morphologies of Steps on Vicinal Surfaces in Molecular-Beam Epitaxy

Abstract

A Monte Carlo model has been used to study growth morphologies of steps on vicinal surfaces in molecular-beam epitaxy. The model accounts for molecule attachment, detachment, and surface diffusion. Through variation of surface temperature, impingement rate of source molecules, and the orientation of vicinal surface, we have explored the surface diffusion and the conditions under which two dimensional nucleation (2DN) growth and step flow (SF) growth occur. We have found optimum growth windows for 2DN growth and SF growth. For SF growth we have found that morphological stabilitity of steps are closely dependent on their step height. Steps with multi-molecular-layers are seen to be less stable than single-layer steps in a surface diffusion field, due to a decrease in the attachment of growth units from the upper terrace.