C-Ni amorphous multilayers studied by atomic force microscopy

Amorphous C-Ni superlattice films designed as normal-incidence reflector fo r 5 nm have been grown on quartz substrate by magnetron sputter deposition. A new digital signal processor-based atomic force microscope (AFM) system has been involved in investigating the surface topography of the final surf ace of the multilayer structure as well as the substrate. In the first step , roughness measurements involving AFM-tips with different radius curvature indicate the C-Ni multilayer surface profile as being in the nanometer and sub-nanometer range, representing a high quality ended surface of the refl ectors. In the second step, a study of the roughness distribution using pow er spectral density functions (PSD) calculated from AFM measurements was pe rformed. The analysis of the amplitudes of the PSD spectra for the multilay er and the substrate surface provided the evidence of the optimized deposit ion parameters. The shape of the PSD curves for multilayer and substrate re veals fractal profiles with the same distribution of the roughness for both of them, attesting the influence of the substrate on the quality of the re flectors. (C) 2000 Elsevier Science B.V. All rights reserved.