An atomistic simulation of the epitaxial growth of silicon(100)

The continuum modeling of epitaxy oil Si(100) surface provides an incomplete description of the process as the growth of single crystal silicon is affected by molecular details of the crystal surface structure. Moreover, the upper limit for the deposition rate of Si atoms for formation of a single crystal is a strong function of surface diffusion and adatom hopping. An integrated model which can combine molecular details with the broader continuum picture is required for successful and complete modeling of this system.; In general, molecular level rate determining steps such is surface diffusion are slow and can not be seen in standard molecular dynamics simulations since these simulation techniques can only cover a few picoseconds of the real process. However, one can force molecular configurations of interest, to be observed in a simulation by the device of adding a molecular scale force field to the equations of motion. We have constructed a simulation scheme based on this strategy and have tested our algorithm by determining various free, energies of different crystal surfaces in FCC and HCP Argon crystals. Argon was chosen because it is, a simpler and better documented system. Many prior existing studies exist with which our codes could be bench-marked.; The main accomplishments of this study were as follows: First determination of the structure of silicon surface by determination of surface free energies in tetrahedral Si crystals and the line free energies of different steps. Second, determination of the surface diffusion rates by deducing the free energy surfaces for the process of hopping between different sites on the surfaces and for the process of jumping over the edge of one layer onto another layer on the crystal surface. Third, determination of the hopping rates of other adatoms like hydrogen on Si(100) surface. Finally, integration of these results with continuum model using an intermediate Monte Carlo modeling to model the coverage of pits in epitaxial process.