Atomic scale study of a MOS structure with an ultra-low energy boron-implanted silicon substrate

In this study, a poly-silicon/oxide on silicon structure was analysed at the atomic scale by atom probe tomography (APT). Before oxidation and poly-silicon deposition, the silicon substrate was implanted with boron (500 eV, 1 × 1015  at cm− 2), post-annealed (650 °C, 30 min, N2) 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.