Interface heterogeneity of periodic multilayer mirrors investigated by X-ray fluorescence, scattering spectroscopy, and mathematical methods of statistics

Multilayer interference structures (X-ray mirrors) based on the alternating layers of Mo/Si and W/Si were investigated using laboratory X-ray micro-fluorescence analysis (micro-XFA) and statistical analysis. The physics of interaction processes of primary X-ray radiation scattered on the surface of multilayer periodic structures have been studied. Using the X-ray spectroscopy together with the mathematical methods of statistics made it possible to evaluate a degree of homogeneity and to compare the chemical compositions of different samples of the multilayer mirrors. A correlation between the statistical characteristics of bimodal frequency distribution and the reflectivity properties of X-ray mirrors for the scattered radiation has been revealed. The frequency distributions of mathematical statistics for experimentally collected intensities of the scattered Rh K alpha radiation indicate the depth heterogeneity of the studied samples. Used in this work approach gives a new strategy for testing to improve of efficiency of X-ray mirrors based on the multilayer nanoscale structures.