Abnormal evolution of resistivity and microstructure of annealed Ag nanoparticles/Ag–Mo films

Ag–Mo films with different thicknesses were prepared on polyimide substrate by magnetron sputtering and annealed at different temperatures. The effects of film thickness and annealing temperatures on the resistivity and microstructure of Ag–Mo alloys were investigated. Results show that many Ag nanoparticles were self-formed on Ag–Mo films’ surface. As the thickness of the Ag–Mo film increased from 163 to 409 nm, there was a significant decrease in its resistivity, dropping from 485.44 to 237.12 μΩ cm. Resistivity of the Ag–Mo film is dependent on the annealing temperature. When temperature rises from room temperature to 180℃, the resistivity decreases from 390.62 to 339.37 μΩ cm, with little change. After annealing above 270℃, a sudden increase of resistivity of the Ag–Mo film was attributed to the growth of Ag particles on the film surface contributing to the increase in surface roughness, which hindered electron transport and caused severe surface scattering. High-resistivity Ag–Mo films are expected to be candidates for high-resistivity thin-film devices.