Physical characterization by valence electron energy loss spectroscopy

The complexity and the size reduction of state of the art CMOS technologies generate a need for advanced physical characterization. The main difficulty is often to achieve the combination of both high spatial resolution and information on the chemical composition or on the physical properties like the k value or the electrical conductivity. One of the aptest methods to give the desired information is electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM) mode, especially in the low loss region. This is demonstrated by performing the nickel silicide phase determination on an encroachment formed by Ni diffusion in active Si.