Scaling behavior and coarsening transition of annealed ZnO films on Si substrate

Using reactive radio frequency magnetron sputtering, ZnO films were deposited on Si (001) substrate at room temperature and were annealed at different temperatures ranging from 300 to 1000 °C in air. The annealing behavior has been studied by analyzing morphological and structural evolution of ZnO films quantitatively. A coarsening transition is found occurring at a temperature of about 790 °C. For the annealed films above and below the temperature, the diffusion mechanisms of oxygen vacancies and zinc interstitials are assigned to be responsible for the coarsening behaviors, respectively.