Energetics of Silicide Interface Formation

The energetics of the early growth stages of epitaxial NiSi₂ on Si have been investigated by use of local-density-functional theory implemented as the linear-augmented-plane-wave method. We find that a proposed diffusion region of interstitial Ni several atomic layers thick is highly unfavorable energetically. The energy difference between interstitial and reacted Ni at monolayer coverage calculated for a (111) surface is less, but still large enough to argue strongly against a significant intersitial concentration for any surface.