Macro- and microstrain relaxation in annealed Ag films during aging at room temperature

摘要

The relaxation of thermally induced strain in 500 nm thick polycrystalline Ag layers electron-beam deposited onto Si wafers was traced during ageing at room temperature. The layers consisted predominantly of matrix crystallites with {111} planes parallel to the surface and twin crystallites with {511} planes parallel to the surface. The macrostrain in the plane of the layer was determined from the X-ray diffraction line-profile position and the microstrain from the diffraction-line broadening. The residual macrostress relaxed from 160 MPa to 30 MPa in the matrix crystallites and from 170 MPa to 50 MPa in the twin crystallites. Simultaneously with the decrease in macrostress the microstrain decreases significantly for both texture fractions. The strain relaxation behaviour is governed by movement and subsequent annihilation of defects in the layer.