DETERMINATION OF INTERFACE ROUGHNESS STATISTICAL PARAMETERS FROM ANGULAR SPECTRA OF X-RAY DIFFUSE SCATTERING A. V. Andreev, Yu. V. Ponomarev, Physics Department, M.V.Lomonosov Moscow State University, Russia Yu.Ya. Platonov, OSMIK, Troy, Michigan, USA, N.N. Salashchenko Institute for Physics of Microstructure, Nizhny Novgorod, Russia

The optimized algorithms for reconstruction of the statistical characteristics of the interface roughness from the angular spectra of the x-ray diffuse scattering have been theoretically developed and experimentally tested.

We report the results of the experimental and theoretical study on the x-ray diffuse scattering by multilayer nanostructures. The theory of the diffuse scattering based on the combination of the two-wave dynamic diffraction and distorted wave approximat ion is developed. In our experiments we have used the x-ray mirrors with the wide range of parameters (periods d=a+b from a few units up to twenty nanometers, consisting of the different pairs of materials and substrates, and different ratios of the lay ers thickness a/d=0.1-0.5).

We have experimentally observed a number of new phenomena which are due to the effects of the dynamic diffraction: effects of the forbidden reflection release, resonant rise of the background intensity, and appearance of the additional maxima of the dif fuse scattering corresponding to the excitation of the second sheet of the dispersion surface. The good agreement of the theoretical and experimental angular spectra of the diffuse scattering enables us to determine with the help of computer fitting the following statistical parameters of the investigated mirrors. The rms height of roughness, longitudinal and transversal correlation lengths.