Hole opening from growing interfacial voids: A possible mechanism of solid state dewetting

Vacancies at interfaces between a film and a substrate can affect material properties and could play a role in solid state dewetting. Using kinetic Monte Carlo simulations, we show that interfacial mono-vacancies diffuse and coalesce to form vacancy clusters and voids. The film/substrate excess energy E-S, which is related to the apparent contact angle, controls the mechanisms of coalescence. Depending on E-S, voids emerging at the film surface form a hole that can be filled by the film or can lead to dewetting of the film from the substrate.