Kinetic Monte Carlo simulation of faceted islands in heteroepitaxy using multi-state lattice model

TL;DR

This paper presents a generalized kinetic Monte Carlo model for simulating faceted island formation in heteroepitaxy, incorporating deformation states to better replicate pyramid-shaped islands on Si substrates.

Contribution

The model introduces deformation state variables to simulate surface reconstructions and faceted island formation in a kinetic Monte Carlo framework.

Findings

Reduced growth rates after faceting

Continuous nucleation of islands

Overcrowding occurs after nucleation

Abstract

A solid-on-solid model is generalized to study the formation of Ge pyramid islands bounded by (105) facets on Si(100) substrates in two dimensions. Each atomic column is not only characterized by the local surface height but also by two deformation state variables dictating the local surface tilt and vertical extension. These deformations phenomenologically model surface reconstructions in (105) facets and enable the formation of islands which better resemble faceted pyramids. We demonstrate the model by application to a kinetic limited growth regime. We observe significantly reduced growth rates after faceting and a continuous nucleation of new islands until overcrowding occurs.