In the present work the effect induced by a thin silicon oxide and its interface with silicon on the quantification of ultra-shallow arsenic distributions measured by secondary ion mass spectrometry (SIMS) has been studied. Three As implants on a 11 nm SiO2/Si stack have been measured: the projected ranges of the arsenic implants were chosen to result in the implants being in oxide, at the SiO2/Si interface and just beyond the interface, respectively. The measurements have been performed by different analytical methodologies using Cs+ primary ions at varying impact energies and collecting the molecular species SiAs-. Different methods of normalization have been studied and the effect of the oxide on RSF variation and dose measurement has been discussed. (C) 2004 Elsevier B.V. All rights reserved.