Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 32: Epitaxie und Wachstum II
O 32.8: Vortrag
Donnerstag, 27. März 2003, 16:45–17:00, FOE/ANOR
Growth and interface atomic structure of B2-FeSi/Si(111) studied by LEED and STM — •M. Krause1, F. Blobner1, S. Walter1, U. Starke1,2, and K. Heinz1 — 1Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
Iron silicide shows a large variety of film phases when grown on Si(111) – with some of them not stable as bulk material. For 1:1 stoichiometry a metastable B2-FeSi-(1×1) phase can be prepared by evaporating iron at RT or below followed by subsequent annealing at about 300∘C. Scanning tunneling microscopy (STM) shows a layer-by-layer growth of silicide bilayers (i.e. of slabs of one Si and one Fe layer) for coverages up to 3 ML Fe. Such a thin film allows to determine the structure of the interface by means of a quantitative low-energy electron diffraction (LEED) structure analysis. It turns out to be of the so-called B8 type, i.e. with Fe atoms adjacent to the Si substrate 8-fold coordinated and a stacking orientation of the silicide film rotated by 180∘ with respect to the substrate stacking. The results are in good agreement with previous density functional theory studies of our group. The successful determination of this interface structure is a key issue for the further investigation of other silicide thin film phases, which evolve from this (1×1) phase by annealing to higher temperatures.