Berlin 2005 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 24: Postersitzung II

DS 24.5: Poster

Dienstag, 8. März 2005, 17:00–19:00, Poster TU B

Origin of the optical anisotropy oscillations during the oxidation of Si(001) — •Frank Fuchs, Wolf G. Schmidt, and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik,
Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany

The oxidation of silicon is both of great fundamental and technological interest. Despite decades of effort, the microscopic mechanisms of oxide growth are still under consideration. Recent experiments [1-4] indicate the high potential of Reflectance Anisotropy Spectroscopy (RAS) for the study of oxide growth on Si(001), where RAS could represent a powerfull supplement to conventional surface characterisation techniques.
Here we present the results of our ab initio study on the origin of the RAS oszillations measured during oxide growth. Our results demonstrate the relation of the RAS oscillations to the layer-by-layer oxidation of Si(001). The major contribution to RAS is found to result from the interface, while the RAS signal from the oxide-overlayer is found to vanish due to surface disorder. The progression of the local strain field accompanying the oxygen-insertion into Si-Si bonds at the interface is identified as the actual origin of the RAS oscillation.

[1] T. Yasuda et al., Phys. Rev. Lett. 87, 037403 (2001).

[2] T. Matsudo et al., J. Appl. Phys. 91, 3637 (2002).

[3] T. Yasuda et al., Phys. Rev. B 67, 195338 (2003).

[4] T. Yasuda et al., Thin Solid Films 455-456, 759 (2004).