In this study, a poly-silicon/oxide on silicon structure was analysed at the atomic scale by atom probe tomography (AFT). Before oxidation and poly-silicon deposition, the silicon substrate was implanted with boron (500 eV, 1 x 10(15) at cm(-2)). post-annealed (650 degrees C, 30 min, N(2)) in order to get a high deactivation rate and to form boron clusters. A good agreement was obtained between the APT and secondary ion mass spectrometry analyses, although discrepancies are observed on the concentration profiles. Those discrepancies appear as boron-silicon clusters, lying on the (001) plane, as previously observed in the literature. (C) 2009 Elsevier B.V. All rights reserved