Molecular-dynamics simulations of solid-phase epitaxy of Si: Growth mechanisms

Abstract

Crystal-growth processes of Si during solid phase epitaxy (SPE) in the [001] direction have been investigated based on molecular-dynamics (MD) simulations using the Tersoff potential. A tetragonal cell including an amorphous/crystalline (a/c) Si interface composed of up to 4096 atoms was taken as the starting system. From the Arrhenius plot of the growth rates obtained by MD simulations, we have found that the activation energy of SPE at lower temperatures is in good agreement with the experimental value (\ensuremath{\approx}2.7 eV), while it becomes lower at higher temperatures. This can be attributed to the difference in the a/c interface structure and SPE mechanism. In the low-temperature region, the a/c interface is essentially (001) and the rate-limiting step is two-dimensional nucleation on the (001) a/c interface. On the other hand, the a/c interface is predominantly composed of {111} facets in the high-temperature region and the rate-limiting step is presumably a diffusion process of Si to be trapped at the kink sites associated with these facets.