Quantitative analysis of oxygen deficiency in epitaxial CeO2 layers on Si by detecting 18O added for stoichiometry

Oxygen deficiency in epitaxially grown CeO2 layers on Si substrates by ultrahigh-vacuum evaporation is studied using secondary ion mass spectrometry (SIMS). 18O2 gas is externally introduced in the evaporation process for compensation of oxygen deficiency of the CeO2 layer. Oxygen components in CeO2 layers are analyzed, separately detecting secondary ions of Cs16O+ and Cs18O+. The extrinsic oxygen content needed to obtain stoichiometric CeO2 is determined to be in the range of 11–18%. These SIMS data agree well with the oxygen deficiency of ~18% determined by Rutherford backscattering analysis of a nonstoichiometric CeO2 layer grown without oxygen gas introduction.