Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Poster: Trends in Ion Beam Technology, Magnetism in Thin Films, Functional Oxides, High-k Dielectric Materials, Semiconductor Nanophotonics, Nanoengineered Thin Films, Layer Deposition Processes, Layer Growth, Layer Properties, Thin Film Characterisation, Metal and Amorphous Layers, Application of Thin Films

DS 17.55: Poster

Dienstag, 26. Februar 2008, 09:30–13:30, Poster A

Preparation of single terminated substrates for oxide superlattices — •Thomas Freudenberg, Ruben Hühne, Bernhard Holzapfel, and Ludwig Schultz — IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany

Well-defined and nearly perfect single crystal surfaces of oxide perovskites are important for the preparation of oxide superlattices with smooth interfaces. Single terminated surfaces of SrTiO₃, NdGaO₃ and YAlO₃ having steps of one unit cell height and atomically flat terraces were obtained by selective etching using various pH controlled hydrofluoric acid solutions. The effect of annealing in an oxygen environment and of etching conditions on the surface morphology was studied by atomic force microscopy (AFM). It has been demonstrated that perfect surfaces can be achieved with a proper selection of both the annealing temperature and the etching parameters with respect to substrate miscut angle. The prepared single terminated substrates were used to study the homoepitaxial growth of SrTiO₃ as well as the heteroepitaxial growth of SrTiO₃ on NdGaO₃ and SrRuO₃ on SrTiO₃. Therefore, pulsed laser deposition in combination with high-pressure reflection high-energy electron diffraction (RHEED) was applied to investigate the influence of the different deposition parameters including background pressure, substrate temperature and repetition rate on the film growth behavior. The observed RHEED intensity oscillations and the surface characterization using AFM indicate that a layer-by-layer growth mode was achieved during homoepitaxial and heteroepitaxial growth.