A Model for Anisotropic Epitaxial Lateral Overgrowth

Date
2001
Authors
Khenner, M.
Braun, Richard J.
Mauk, M.G.
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Mathematical Sciences
Abstract
The model for anisotropic crystal growth on a substrate covered by a mask material with a periodic series of parallel long trenches where the substrate is exposed to the vapor phase if developed. The model assumes that surface diffusion and deposition flux are the main mechanisms of the growth, and that the three key surface quantities (energy, mobility and adatom diffusivity) are anisotropic with either four- or six-fold symmetry. A geometrical approach to the motion of crystal surface in two dimensions is adopted and nonlinear evolution equations are solved by a finite-difference method. The model allows the direct computation of the crystal surface shape and the study of effects due to finite mask thickmness. As in experiments, lateral overgrowth of crystal onto the mask if found, as well as comparable crystal shapes; the anisotropy of the surface mobility is found to play the dominant role in the shape selection. The amount of the overgrowth and the shapes can be effectively controlled by orienting the fast and slow growth directions with respect to the substrate.
Description
Keywords
selective epitaxy , vapor phase epitaxy , epitaxial lateral overgrowth , computer simulation
Citation