GEOMETRIC AND ELECTRONIC-STRUCTURE OF EPITAXIAL IRON SILICIDES

The geometric and electronic structure of several iron silicide phases epitaxially grown on Si(111)7X7 have been characterized by means of surface sensitive techniques including scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy, ion scattering spectroscopy (ISS), and ultraviolet photoelectron spectroscopy. The silicides were grown by solid-phase and reactive-deposition epitaxy, and their stability range was determined in situ as a function of iron coverage and annealing temperature. In particular, we have studied the phases appearing in the low-coverage low-temperature region. Additionally, the crystallites of the most important FeSi2 phases (gamma-FeSi2 and beta-FeSi2) have been characterized at atomic level with STM, while the surface termination was analyzed with ISS.