Monte Carlo simulation of growth and recovery of silicon

We report on the results of Monte Carlo (MC) simulation of epitaxial growth dynamics of Si(001). We propose an MC model which allows the formation of bulk vacancies and overhangs in the tetrahedral lattice structure of silicon. The surface relaxation (dimerization) as well as atom-atom interactions extending as far out as second-neighbor sites are included in the model. Our results demonstrate that the effect of the formation of vacant sites is pronounced only at low temperatures (T = 500-700 K) where there is no active hopping of atoms. At high temperatures (T > 800 K) this effect is washed out by intensive hopping of atoms. We found that in the temperature range 700-800 K growth mode changes from rough three-dimensional growth to smooth two-dimensional growth. Simulation of silicon recovery after interuption of growth showed that there are two different mechanisms of recovery. At low temperatures (T = 500-600 K) the recovery of the crystal surface is provided by the hopping of surface atoms residing in the vicinity of vacant sites. At high temperatures (T > 700 K) it is caused by the hopping of bulk atoms.