ROUGHNESS OF SURFACES AND INTERFACES

X-ray reflectivity is now a common tool for investigating density prof iles of thin films and multilayers in a nondestructive manner. In cont rast to the specularly reflected beam the nonspecular diffuse intensit y is sensitive to the lateral structure of rough interfaces. The most reliable results are obtained from simultaneous fits of all available data (i.e. reflectivity together with all diffuse scans) with a single set of parameters. It turns out that diffuse scattering experiments f rom a large class of systems can be described by correlation functions of self-affine fractal surfaces. Two layer systems serve as test case s: (1) A CoSi2/Si-layer system grown by molecular beam epitaxy (MBE) a nd (2) Langmuir-Blodgett films. The analysis within the distorted-wave Born approximation (DWBA) of the scattering from the silicide sample gives a large amount of information, e.g. strong vertical correlations . For the topmost surface a comparison between scanning tunneling micr oscopy (STM) and X-ray results leads to very good agreement. Nine and eleven monolayer Langmuir-Blodgett films with high defect concentratio ns also can be successfully analyzed with the fractal model. The later al lengths obtained from the diffuse scattering and grazing-incidence diffraction (GID) agree.