Long-term evolution of Ti-Cu amorphous film: Agglomeration and crystallization behaviors of Cu

Abstract

Sometimes the films deposited by magnetron sputtering are in a metastable state. The films tend to transition to the equilibrium phase, which is crucial for the stability of the microstructure and properties of the films in practical applications. In this study, Ti-Cu films were deposited using a high-power pulsed magnetron sputtering technique, and the evolution of the microstructure of the film under natural aging and thermal aging conditions was systematically investigated. The results showed that the as-deposited Ti-Cu film was amorphous, and as the aging time increased, particles comprising Cu agglomerates and crystalline phases were gradually formed in the film. During aging treatments, Cu agglomerates at the Ti-Cu film led to strong scattering and absorption of the incident light, resulting in reflectance losses. Cu agglomerates at the film was more intense under thermal aging conditions than under natural aging conditions, which was attributed to the fact that the provision of additional temperature could accelerate the diffusion of the smaller Cu atoms in the Ti-Cu amorphous film. Exploring the long-term evolution of the Ti-Cu film structure will provide theoretical guidance for the stability of films in practical applications.