Surface anisotropy characterization and microstructure of Cu–W thin films at different annealing temperatures

Abstract

Cu–W films were deposited on Al 2O 3 substrates by magnetron sputtering and then annealed in Ar gas at different temperatures for an hour. The evolution of surface morphology of the films during deposition and annealing was investigated by mathematical techniques. A strategy integrating discrete wavelet transform and fractal geometry concepts was developed for analyzing the anisotropy of surface structure of Cu–W thin films. The results indicated that the agglomeration of Cu–W thin films occurs primarily during annealing process. Based on the observation of positive correlation between the surface anisotropy and W-like phase transition, the relationship between the evolution of surface morphology of Cu–W thin films and the transition of phase structure was constructed. It was concluded that the changes of phase structures could have a significant impact on the anisotropy behavior of surface structure of Cu–W thin films.