X-ray diffraction line broadening from thermally deposited gold films

Diffraction profiles were analysed from thermally deposited 111-oriented gold films, ranging in thickness from 300 to 1900 Å. The data were collected using the high-resolution powder diffractometer on beamline BM16 at the European Synchrotron Research Facility (ESRF) set at a wavelength of 0.3507 Å. The profiles were measured under conventional symmetric θ–2θ reflection conditions and by asymmetric transmission diffraction to ensure that only crystallites oriented normal to the substrate contribute to the diffraction. An analysis of the instrument profile shape of the diffractometer was undertaken using the SRM 660 LaB₆ line profile standard. A parallel study of the films using atomic force microscopy and transmission electron microscopy was also undertaken to provide information on the dimensions of the crystallite columns in the films and the presence of dislocations. All the films displayed diffraction broadening arising from both crystallite-size effects and dislocation-induced strain effects. Analysis of the magnitude and anisotropy of the dislocation-induced broadening with hkl indicates that the dislocations have a mixed screw/edge character and tend to form primarily on (111) slip planes parallel to the substrate at densities of ∼10¹⁵ to 10¹⁶ m⁻².