An x-ray line shift analysis in vacuum-evaporated silver films

Thin films of silver of thickness 58-212 nm (580-2125 Å) were prepared by evaporation on glass substrates at a residual air pressure of similar 10 −5 Torr, and x-ray diffraction line profiles were chart-recorded on a Geiger counter x-ray diffractometer at room temperature using Cu K α radiation. The peak positions of 111, 200, 220 and 311 reflections were measured, and from the peak shifts of adjacent pairs of reflections the lattice parameter changes, residual stresses and stacking fault concentrations in the films were determined as a function of film thickness. In relatively thin films (<100 nm), an appreciable decrease in the lattice parameter from the bulk value and a predominance of extrinsic stacking faults were observed. The residual stresses in the plane of the films were found to be compressive in nature, varying from similar 0·17 to similar 0·01×10 10 N m −2 (similar 24 to similar 1×10 4 psi) with the increase in thickness. The results have been analysed and discussed in the light of existing work on thin metallic films.