Resolving the W-on-Si interface by non-destructive low energy ion scattering

We present the use of Low Energy Ion Scattering (LEIS) as a non-destructive technique for characterizing the W-on-Si interface. LEIS spectra inherently contain depth-resolved information in the subsurface signal. However, assisting the spectra analysis with simulations is necessary for extracting quantitative information about the sample's depth composition. In this study, we compare measured and simulated LEIS spectra of W thin films on Si. These results prove, for the first time, the applicability of the method to probe a complex interface formed by a thin film of heavier atoms deposited on a film of lighter atoms. W/Si thin-film structures are used in X-ray optics, where precise control over interface composition is essential. Our findings affirm LEIS as a valuable technique for characterizing these interfaces with sub-nanometer accuracy.