X-ray reflection and diffuse scattering from sputtered gold films

Gold films were prepared by DC sputtering on quartz glass substrates under two different conditions, once in argon at 3 x 10(-3) mbar (Au1-films), and once in residual air at 0.3 mbar (Au2-films). Specular X-ray reflection showed that the surface of the Au1-films was as smooth as that of the substrate, whereas the Au2-films were distinctly rougher. The diffuse scattering could be measured with a laboratory equipment by recording rocking curves and detector scans. The application of existing theories to the diffuse scattering data showed that slight modifications of the given equations were necessary. With these modifications the experimental data could be fitted very well, and the height-height correlation functions of the surfaces of the films and of the substrate were determined. In the Au1-films the surfaces of the film and the substrate are perfectly correlated, whereas in the Au2-films no cross correlation is found. (C) 1998 Elsevier Science B.V. All rights reserved.