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

Yamamoto, Hiroyuki; Yamada, Yoichi; Sasase, Masato*; Esaka, Fumitaka  

Non-destructive depth profile analysis with better depth resolution is required for the characterization of nano-materials. 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. 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. In the present study, Ge thin films (2,4 nm) on two different Si substrates (hydrogen terminated, native oxide) has been analyzed to obtain depth profile of the thin film and buried interface of Ge/Si under the film with two different Si substrates. The XPS spectra clearly show the difference obtained from the varied analyzing depth. These results suggest that the SR-XPS can be applicable for non-destructive depth profile analysis of surface and buried interface.