Texture formation in Ag thin films: Effect of W–Ti diffusion barriers

Abstract

Pure Ag films were deposited on SiO2/Si with and without introduction of W0.7Ti0.3 barrier layers. The films were annealed in vacuum for 1 h at temperatures up to 650 °C. X-ray diffraction pole figure analysis was used to investigate the texture information in as-deposited and annealed films. After annealing, the {111} texture in Ag films increased; however, the degree of increase was significantly higher in Ag/W–Ti/SiO2. In Ag/SiO2 structures, the {200} texture also increased. In Ag/W–Ti/SiO2 structures, no significant increase in {200} texture was observed; however, {111} twin related {511} texture evolved. In as-deposited samples, {111} pole figure revealed that {111} absolute intensity was higher in Ag/SiO2 than in Ag/W–Ti/SiO2. After annealing, Ag {111} intensity was always higher in Ag/W–Ti/SiO2. Sources for the texture evolution were discussed in detail. Field emission scanning electron microscope showed the presence of twins and abnormal grain growth. After annealing at 650 °C, both the roughness and resistivity of Ag increased significantly.