Soft X-ray emission spectroscopy study of CaF,(film)/Si(l 11): non-destructive buried interface analysis

A soft X-ray emission spectroscopy (SXES) study under an energetic electron irradiation is first applied to a non-destructive buried interface analysis of a CaF,(film M 40 nm)/Si(ll 1) contact system, where the energy of primary electrons, Ep, is I 5 keV. The present work has explored the usefulness of the application of the SXES method to the interface study to give rise to the following findings: the CaF,/Si(l 11) interface shows rather sharp transition from the top Cal?, to the substrate Si, there certainly is a Ca-silicide layer at the CaF,/Si(l 11) interface, the thickness of the silicide layer is estimated to be less than several nm, and the e-beam excited SXES non-destructive study is very powerful to analyze a specimen with rather thick top film (> 40 nm) and thin interface layer ( < several nm).