Boron (BF(2), 20 keV, 3.14/cm(2)) and carbon (13 keV, 10(15)/cm(2)) implanted silicon annealed at 800 degrees C during 30 min or at 1000 degrees C during 10 s has been investigated using a laser-assisted wide-angle tomographic atom probe (LaWaTAP) instrument. Boron-silicon clusters containing similar to 1 3 at % of boron atoms have been observed in boron implanted silicon with a concentration exceeding the solubility limit. Often identified as BICs. they are interpreted as a metastable phase Furthermore, addition of carbon clearly reduced the clustering of boron. This was interpreted as a diminution of boron diffusion or as an increase of the Solubility limit of boron Carbon-silicon clusters containing similar to 1.5 at % of carbon atoms were observed, maybe the precursors of the SiC phase (C) 2009 Elsevier B V All rights reserved