Grazing incidence X-ray photoemission spectroscopy of SiO2 on Si

We have applied grazing incidence X-ray photoemission spectroscopy to the d etermination of the thickness of SiO2 layers on Si, as well as surface carb on that is present. The measurements take advantage of the different optica l constants of the layers. X-rays incident on the surface at grazing angle undergo total external reflection, where the fields in each layer are subje ct to highly non-linear changes as a function of incidence angle. X-ray pho toemission excited by these fields gives information on atomic species, che mical state, and layer thickness. Simultaneous fits are made to the photoem ission spectra in each layer. The method is illustrated for a thermally gro wn oxide layer and a native oxide on Si. (C) 1999 Elsevier Science B.V. All rights reserved.