Phase-field modeling of epitaxial growth with the Ehrlich-Schwoebel barrier: Model validation and application

Abstract

In this paper, we introduce different forms of mobility into a quantitative phase-field model to produce arbitrary Ehrlich-Schwoebel (ES) effects. Convergence studies were carried out in the one-side step-flow model, which showed that the original mobility not only induces the ES effect, but also leads to larger numerical instability with increase of the step width. Thus, another modified form of the ES barrier is proposed, and is found to be more suitable for large-scale simulations. Model applications were performed on the wedding-cake structure, coarsening and coalescence of islands and spiral growth. The results show that the ES barrier exhibits more significant kinetic effects at the larger deposition rates by limiting motions of atoms on upper steps, leading to aggregation on the top layers, as well as the roughening of growing surfaces.