Monte Carlo Simulations of Molecular Beam Epitaxy on Si(001) Surfaces

Results of a Monte Carlo simulation of crystal growth on Si(001) surfaces by molecular beam epitaxy are presented. The simulation is based on the solid-on-solid model and depicts the diamond lattice and surface reconstructions explicitly. Deposition of two or more different atomic species, surface diffusion, and the formation and reorientation of surface dimer pairs are accounted for. Initial simulations of Si homoepitaxy showed that two parameters, the second-nearest neighbor interaction energy, E₂, and a surface dimer interaction energy, E_n, were critical for obtaining realistic simulations. E₂>kT was required for obtaining layer-by-layer growth and flat (001) surfaces. E_n was also >kT in order to obtain a (×1$/) surface reconstruction. Reflected electron intensity calculations for growth under these conditions on exactly (001)-oriented surfaces showed strong intensity oscillations with a period of 1 monolayer, while growth on °-misoriented vicinal surfaces yielded no oscillations. Simulations of heteroepitaxy showed that the surface morphology during the initial nucleation stages depended strongly on the growth kinetics as well as interfacial energies.