Quantitative depth-dependent analysis using the inelastic scattering backgrounds from X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy

The inelastic scattering contribution to an X-ray photoelectron spectrum (XPS) reflects the distribution of elements within the sample depth. Varying the energy of the incident photons changes the inelastic scattering contribution. We present a standardless, automated method that exploits this change to enable compositional analysis within the XPS information depth (also known as amount of substance, AOS(3 lambda)). In this method, the photoelectron intensities observed using two or more X-ray photon energies are normalised using correction factors. These correction factors are derived to determine the AOS(3 lambda) from the inelastic scattering signals collected from different samples. The AOS(3 lambda) are then compared with the ratio of the elastic XPS peak intensities calculated for different sample depths to find the layer thickness. The method has been applied to analyse spectra collected from thin amorphous carbon films to yield quantitative, standardless and automated XPS analysis.