Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Nanostructures at Surfaces VI (Surface Reconstructions)
O 66.1: Vortrag
Freitag, 30. März 2007, 10:15–10:30, H36
Morphology and growth of hafnium silicide on Si(111) — •Eva Henschel1, Mark Schürmann1, Christian Flüchter1,2, Daniel Weier1,2, Axel Beimborn1, and Carsten Westphal1,2 — 1Experimentelle Physik 1 - Universität Dortmund, Otto-Hahn-Str.4, D 44221 Dortmund, Germany — 2DELTA -Universität Dortmund, Maria-Goeppert-Mayer-Str. 2, D 44221 Dortmund, Germany
The structure and growth of hafnium on Si(111) were studied by scanning tunneling microscopy (STM). Hafnium was deposited by electron beam evaporation onto a clean Si(111) surface under UHV-conditions. The sample was heated in several steps to 900∘C. A growth of elongated nanosized structures was observed. Since it is known that hafnium on silicon forms silicide compounds [1], the islands are assumed to consist of HfSi2. The islands were found to grow in three main directions, related to the symmetry of the (111) surface.
The morphology of these silicide islands is affected by the annealing temperature. The first structures were observed after annealing at 450∘C and the first free standing islands were found at 650∘C. The islands grow in all three dimensions simultaneously, although the growth of length, width and height starts at different temperatures.
With increasing island volume the island number decreases. An analysis of the mean coverage was performed which indicated a possible decrease of the hafnium amount on the surface. Furthermore, the influence of step edges on the island distribution was studied.
[1] A. de Siervo et al., Phys. Rev. B 74 (7), (2006) 075319