Rutherford backscattering spectroscopy of rough films: Experimental aspects

We present experimental aspects of a new approach for the analysis of Rutherford backscattering spectra of rough films. Using some simplifying assumptions, we obtain equations which relate the height distribution of a rough film on a smooth substrate to the backscattering spectrum produced by the film anti by the substrate. As an experimental test case, we chose the system indium on silicon. Polycrystalline indium films with thicknesses ranging from 3 to 600 nm were deposited on single-crystalline, polished silicon wafers using different substrate temperatures. Thus, it was possible to obtain films with a large variation in their height distributions which are analyzed by means of their backscattering spectra. The advantages and limitations of this new type of roughness analysis are discussed. (C) 1998 Elsevier Science B.V.