X-Ray Residual Stress Gradient Analysis in Annealed Silver Thin Films Using Asymmetric Bragg Diffraction

Residual stresses were determined in magnetron-sputtered Ag thin films of 400 nm thickness by asymmetric Bragg scattering. The corresponding cos(2 alpha)sin(2) psi plots were nonlinear which indicates a strong residual gradient along the depth of the samples. The in-plane stress was highly compressive at the sample surface and became tensile at the interface. The out-plane stress was compressive and reached its maximum at the sample interface. The stress gradient changed significantly with post-annealing temperature. A Young's modulus of E = 83 GPa and a Poisson ratio of v = 0.3 were measured by surface acoustic wave dispersion.