Dresden 2011 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 42: Poster I: Progress in Micro- and Nanopatterning: Techniques and Applications (jointly with O); Spins in Organic Materials; Ion Interactions with Nano Scale Materials; Organic Electronics and Photovoltaics; Plasmonics and Nanophotonics (jointly with HL and O); High-k and Low-k Dielectrics (jointly with DF); Organic Thin Films; Nanoengineered Thin Films; Layer Deposition Processes; Layer Properties: Electrical, Optical, and Mechanical Properties; Thin Film Characterisation: Structure Analysis and Composition; Application of Thin Films

DS 42.97: Poster

Mittwoch, 16. März 2011, 15:00–17:30, P1

Model calculations for XRD at polycrystalline thin films — •Susanne Hahne, Thomas Weisemoeller, and Joachim Wollschlaeger — Department of Physics, University of Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany

The evaluation of x-ray diffraction (XRD) data is an important method for structure determination. Regarding thin films the theoretical description of XRD is commonly based on an ideal lateral and vertical structure without defects to determine lattice constants and the film thickness. This contribution introduces a new 2D model, which includes defects of the thin film. It replaces the ideal layer with a distribution of crystallites, which cover the substrate surface completely. Their sizes are randomly distributed according to a Γ-distribution. The new model is primarily characterized by the additional dimension, which allows the reproduction of in-plane and out-of-plane data. Two types of crystallite distributions are implemented. For one type the crystallite positions are fixed to certain substrate atoms. The other type assumes a floating film. A first survey verified that the influence on the diffraction pattern of every parameter in the model is correctly reproduced. This includes a variation of the vertical lattice constant, which changes the diffraction peak position. The peaks out-of-plane are broadened, if the vertical crystallite size is decreased. For scattering vectors, which do not coincide with crystal truncation rods, strong fringes are observed. Their oscillation is strongly attenuated with a growing variance of the crystallite height distribution. Similar results are obtained with respect to the lateral crystallite sizes.