STUDY OF THE SURFACE, INTERFACE, THIN FILM AND MULTILAYER STRUCTURES USING X-RAY SCATTERING

David Rafaja, Radomir Kuzel

Department of Electronic Structures, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, CZ-121 16 Prague, Czech Republic

Interaction of X-rays with matter is characteristic by two features – high absorption and negligible refraction described by index of refraction, which is slightly less than unity. Both these characteristics favour the X-ray scattering for investigation of low-dimensional systems. Variety of X-ray diffraction methods is employed in the thin films and multilayers analysis to get an efficient tool for the study of real structure and microstructure of low-dimensional systems over several orders of magnitude. A majority of the experimental methods was adopted from powder diffraction. Nevertheless, some of them are better established in the single-crystal diffraction. A brief overview of experimental techniques utilised in the analysis of low-dimensional systems covers the first part of the lecture.

Applications of the X-ray scattering for the investigation of thin films and multilayers are illustrated on various examples, which cover the phase analysis, the residual stress measurement, determination of the crystallite size and preferred orientation of crystallites in polycrystalline thin films of uranium nitrides, study of heteroepitaxy in the (Ba,Sr)TiO₃/Al₂O₃ system and investigation of the real structure in periodic multilayers (Fe/Au) and in highly disturbed periodic multilayers (Fe/Au). The experimental methods discussed in detail are the symmetrical wide-angle X-ray diffraction, glancing angle X-ray diffraction, reciprocal space mapping, and small-angle X-ray scattering.