Simulation of morphological evolution and crystallographic tilt in heteroepitaxial growth using phase-field crystal method

Abstract

The phase-field crystal (PFC) model is employed to study the morphological evolution and the crystallographic tilt of heteroepitaxial growth on vicinal substrates. The results are as follows: for heterostructures with large misfit (ε > 0.08) the crystallographic tilt of epitaxial layer is approximately proportional to the substrate miscut angle, while the elastic strain energy of the film will lead to the nucleation of dislocation, which contributes to step-flow growth mode. As for the heterostructures with small misfit (ε < 0.04) the elastic strain energy will be released in the form of surface energy, and the surface profile of epitaxial film is dislocation-free island. When exposed to high undercooling, the substrate with large misfit and miscut angle will result in small-angle grain boundary between the substrate and the epitaxial layer. The small-angle grain boundary is composed of arranged dislocations, and it significantly changes the growth orientation of epitaxial layer.