Thin Ca films were evaporated on Si(1 1 1) under UHV conditions and subsequently annealed in the temperature range 200-650 degreesC. The interdiffusion of Ca and Si was examined by ex situ Auger depth profiling. In situ monitoring of the Si 2p core-level shift by X-ray photoemission spectroscopy (XPS) was employed to study the silicide formation process. The formation temperature of CaSi2 films on Si(1 1 1) was found to be about 350 degreesC. Epitaxial growth takes place at T greater than or equal to 400 degreesC. The morphology of the films, measured by atomic force microscopy (AFM), was correlated with their crystallinity as analyzed by Xray diffraction (XRD). According to measurements of temperature-dependent I-V characteristics and internal photoemission the Schottky-barrier height of CaSi2 on Si(1 1 1) amounts to qPhi(Bn) = 0.25 eV on n-type and to qPhi(Bp) = 0.82 eV on p-type silicon. (C) 2002 Elsevier Science B.V. All rights reserved.