A model for Si molecular-beam epitaxy based on scanning tunneling microscopy observations and computer simulations

Abstract

Scanning tunneling microscopy observations of homoepitaxial growth on vicinal Si(001) and of coarsening of Si islands are used to develop a model of growth based on a configuration-dependent activation energy to hopping. In the model four contributions to this energy barrier are proposed: the activation energy to surface diffusion Es, the dimer formation energy Ed and two directional interaction energies between neighboring atoms not forming a dimer, E∥ and E⊥. Monte Carlo simulations are employed to compare experimental results with the results of the tested model and to deduce the atomic interaction energies: Es=(1.15±0.1) eV, Ed=(0.45±0.10) eV, E∥=(0.20+0.2−0.14) eV, E⊥=(0.10+0.1−0.07) eV. Preliminary results of simulations, including anisotropic diffusion, are presented.