Uniformity and stoichiometry of solid phase epitaxial CoSi2films were investigated by Rutherford backscattering spectroscopy (RBS) and scanning electron microscopy (SEM). In a series of samples, small deviations of the composition ratio from the silicide stoichiometry were always observed in the RBS spectra for the films. Furthermore, it was found from SEM observation that these films were not uniform and the surfaces of the samples consisted of two kinds of materials. From these results and the spectra of micro Auger electron spectroscopy, it was concluded that the surfaces of the samples consisted of a stoichiometric CoSi2region and exposed Si regions.