Description:
<jats:p>Epitaxial nickel silicide films grown on Si(111)-(2×1) surfaces have been studied by valence and core level photoemission using synchrotron radiation. The different chemical binding states of the nickel atoms were clearly identified in the valence-band spectra, and our data demonstrate that NiSi2 forms at lower temperatures than previously assumed. The growth of these epitaxial layers is always accompanied by the outdiffusion of silicon atoms, which exhibit an epitaxial arrangement on the silicide surface. By means of depth profiling using tunable synchrotron radiation we were able to determine the thickness of the topmost silicon layer.</jats:p>