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

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 degrees 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 degrees C, both the roughness and resistivity of Ag increased significantly.