ADATOMS, STRINGS AND EPITAXY ON SINGULAR SURFACES

A computer simulation has been developed to describe epitaxy mediated by random nucleation and anisotropic growth of orthogonal "strings". The simulation efficiently combines Monte Carlo techniques for randomizing the spatial location of events with a rate equation for determining the time step between events. In all cases, after initiation of epitaxy, the layer distribution of surface atoms evolves towards a pseudo-steady state which is symmetric, Gaussian, and from which surface diffraction intensities oscillate persistently. As the ratio between string nucleation and growth rates increases, this steady-state distribution widens, and the oscillation amplitude decreases. The simulation represents a simplified subset of the growth rules thought to govern molecular beam epitaxy of Si on Si(001). © 1990.