Voids in thin silver films

Abstract
A high density (1010−1012 cm−2) of small voids (< 15 Å) has been observed in as-deposited thin silver films prepared by cathodic sputtering using high-resolution electron microscopy. The annealing behaviour of these voids has been studied as a function of annealing time and thickness of the films. It has been observed that the size of the voids and the crystallites grow as a result of annealing and, after a certain stage of annealing, a large number of voids are accumulated at the grain boundaries thus inhibiting the grain coarsening by high-angle grain boundary migration. Vacancies trapped in the films and their migration offer a suitable mechanism of void growth observed in the present case.