Atomistic simulations of solid-phase epitaxial growth in silicon

High-quality semiconductor crystals can be produced by solid-phase epitaxial growth at the amorphous-crystal interface. Despite extensive experimental studies, the microscopic mechanisms that lead to crystallization are not known. Molecular-dynamics simulations of a Si(001) amorphous-crystal interface, using an accurate empirical interatomic potential, give an activation energy (for T>950 K) and a shape for the activated state that are in reasonable agreement with experimental measurements. Analysis of the simulations reveals complex microscopic mechanisms involving one or several consecutive atomic rearrangement steps; the unanticipated level of complexity casts doubt on the common viewpoint of a unique mechanism.