Atomic structure of the reactive Fe/Si(111)7x7 interface

© 1997 The American Physical Society. This work was financed by DGICYT (Spain) under Grant No. PB-94-1527 and Grant No. PB-94-0022-C02-01. The access of A.M. and E.G.M. to LURE, Centre Universitaire Paris-Sud, was supported through the Large Scale Facilities program of the European Union. A.M. thanks Eusko Jaurlaritza for financial support. We thank Dr. V. Fritzsche for providing us with the multiple scattering code.
The early stages of Fe/Si(111) interface formation have been investigated using x-ray photoelectron diffraction. Deposition of Fe in the range of one monolayer on Si(111)7x7 at room temperature results in the destruction of the 7x7 reconstruction. After a slight anneal, a well ordered interface is formed. This reacted layer is terminated by a top Si bilayer, which is rotated 180 degrees with respect to the substrate stacking sequence. Fe atoms occupy substitutional Si lattice sites in the next bilayer underneath, keeping an interface coordination similar to the eightfold type. Thus, this initial interface already exhibits several of the most important features of thicker epitaxial silicide films. This result is evidence of the importance of the earliest stages of epitaxial growth to understand the properties of thicker layers.
DGICYT (Spain)
European Union
Eusko Jaurlaritza
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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