Surface-energy-driven abnormal grain growth in Cu and Ag films

A comparative investigation has been made for Cu and Ag films in three states (as-deposited, attaching films after annealing, and free-standing films after annealing) by XRD and TEM. XRD patterns show that, after annealing at 300°C for 2.5 h, (1 1 1) peak increased obviously in both free-standing Cu and Ag films, on the contrary, (2 0 0) and (2 2 0) peak increased obviously in attaching films. In addition, a (1 1 1)-oriented abnormal large grain was observed in both free-standing Cu and Ag films with TEM, while (1 0 0) and (1 1 0)-oriented abnormal large grains appeared in attaching Cu films and a (2 1 l)-oriented abnormal grain appeared in attaching Ag films. The experimental results have been explained satisfactorily by the minimizations of surface energy and strain energy.