Non-destructive depth profiling of solid surface by X-ray absorption spectroscopy with energy selective detection of electrons

Nojima, Takehiro; Esaka, Fumitaka  ; Yamamoto, Hiroyuki

X-ray absorption spectroscopy (XAS) is one of the techniques for surface analysis of solids. Since the near edge structure depends on the chemical states of elements, XAS is widely applied to chemical states analysis. In this study, an XAS method was examined to perform depth profiling by changing electron energy for detection. Gold thin films with the thicknesses of 1, 2, 5 and 10 nm were deposited on Si(100) substrates by resistance heating. In XAS analysis, we measured Si-K edge and Au-M edge spectra of the films by detecting electrons with energies ranging from 5 to 50 eV. In the analysis of the Au thin film with a thickness of 5 nm, electron energy dependence of Au/Si ratio was clearly observed. In addition, similar electron energy dependences were observed for other Au thin films with the thicknesses of 1, 2 and 10 nm. These results indicate that this method is effective for non-destructive depth profiling of solid surface.