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O: Oberflächenphysik

O 29: Poster session II (Nanostructures, Magnetism, Particles and clusters, Scanning probe techniques, Time-resolved spectroscopy, Structure and dynamics, Semiconductor surfaces and interfaces, Oxides and insulators, Solid-liquid interfaces)

O 29.66: Poster

Mittwoch, 29. März 2006, 14:30–17:30, P2

A Photoelectron Diffraction Investigation of the SiO₂/4H-SiC(0001) Interface — •Mark Schürmann, Stefan Dreiner, Ulf Berges, and Carsten Westphal — Universität Dortmund, Experimentelle Physik 1, Otto-Hahn-Straße 4, 44227 Dortmund, Germany

In our study we used photoelectron diffraction to investigate ultrathin SiO₂-films on 4H-SiC(0001). Synchrotron radiation with high flux and sufficient spectral resolution of the U41-PGM beamline at BESSY 2 (Berlin) was used. It was possible to separate individual spectral components in the XPS spectra. These components display different diffraction patterns due to the different local atomic environments of the respective emitters. We present a comparison between experimental data of a thermally oxidized ultrathin oxide layer showing no long-range order and an ordered silicate layer. From the diffraction patterns of the Si⁺ component originating from silicon emitters at the interface it is possible to conclude that the local atomic struture at the interface is very similary for both samples. However, the diffraction of the SiO₂ component is different for both patterns and a comparison with simulations shows, that this difference is a result of the local order within the oxide film. Furtheron, an R-factor analysis of the Si⁺ diffraction reveals details about the local atomic structure of the interface between bulk SiC and non-ordered SiO₂.