Non-destructive depth profile analysis for surface and buried interface of Ge thin film on Si substrate by high-energy synchrotron radiation x-ray photoelectron spectroscopy

Abstract

Non-destructive depth profile analysis with better depth resolution is required for the characterization of nano-materials and their fabrication. X-ray photoelectron spectroscopy (XPS) is the typically non-destructive analysis, however, XPS with fixed excitation energy source cannot provide depth profile without additional technique, such as ion beam sputtering. On the other hand, analyzing depth of XPS can be varied with the energy tunable excitation source, such as the synchrotron-radiation (SR), since the escape depth of the photoelectrons depends on their kinetic energy. We can obtain the XPS spectra from different analyzing depth by varying excitation energy. This technique can provide depth profile non-destructively. In the present study, Ge thin films on Si substrate has been analyzed to obtain depth profile of the thin film and buried interface of Ge/Si under the film.