Dresden 2006 – wissenschaftliches Programm
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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 29.75: Poster
Mittwoch, 29. März 2006, 14:30–17:30, P2
Surface morphology of epitaxial lattice-matched Ba0.7Sr0.3O on the Si(001) surface — •Dirk Müller-Sajak, Jan Zachariae, and Herbert Pfür — Institut für Festkörperphysik, Abtl. Oberfächen, Universität Hannover, Appelstr. 2, 30167 Hannover
Recently we have shown that Ba0.7Sr0.3O as a high K gate dielectric offers an adequate band gap, an appropriate band alignment and a atomically sharp interface to the Si(001) substrate [1].
Here we will present a SPA-LEED (Spot Profil Analysis LEED) study of the Ba0.7Sr0.3O surface morphology.
The vertical roughness was determined to be ≤ 2ML at up to 15 nm layer thickness. In addition, local variations of the lattice spacing due to fluctuations of the local composition were detected in our G(S) analysis.
Growth of Ba0.7Sr0.3O on vicinal Si(001)-[011]4∘ leads to stepped oxide surfaces. The spot splitting is 4% of the surface Brillouin zone for the oxide surface in contrast to 10% for vicinal Si(001).
This indicates a uncorrelated mixture of terraces separated by triple steps and double steps in molecular units. This is mainly caused by a rearrangement of the vicinal Si(001) surface due to the preadsorbed Sr layers, which is necessary for the crystalline growth of Ba0.7Sr0.3O [1].
Pd chains which nucleate along these steps were investigated by ARUPS and SPA-LEED. The structure of this 1D electronic system will be discussed.
[1] J. Zachariae and H. Pfnür, Phy. Rev. B 72, 075410 (2005)