SURFACE ROUGHENING AND SURFACE-DIFFUSION IN KINETIC THIN-FILM DEPOSITION

We have studied the correlation between surface roughening and surface diffusion in kinetic thin-film deposition by Monte Carlo simulation. Through a variation of simulation parameters, we have obtained an optimal deposition window for layer-by-layer growth in the parameter space of temperature and impingement rate. We have found that an atomically smooth surface can only be obtained at a regime of intermediate temperatures and low impingement rate, beyond which the growing surface is either kinetically rough (at low temperatures) or thermally rough (at high temperatures). The kinetic roughening can be avoided by choosing a lower deposition rate, but the thermal roughening cannot be compensated by any choice of particle impingement. We have shown that surface diffusion is closely correlated with surface roughening. Only when the surface diffusion length is long can a surface be grown in a layer-by-layer mode.