Composition profiling of a SiGe multilayer. (a) Experimental (black) and reconstructed (red) Raman spectra. The blue spectra are the weighted ϕ
components. The upper reconstructed spectrum is the result of the minimization of Equation 1, while the lower reconstructed spectrum is generated from the thickness values obtained by SEM. (b) Relative spectral contributions, a
, with respect to the composition. (c) Composition profile of the multilayer given by the Raman measurement compared to the profile obtained by SEM. In the inset of (c) a cross-sectional SEM image (the scale bar is 100 nm) with the thickness of the layers is reported. The height from the substrate surface is z. The deepest layer, with x = 0.8, was not included in the Raman analysis (see text).