Scanning electron microscopy and nuclear reaction analysis have been used to study annealing effects of 10 keV C-12 implanted and electron beam annealed silicon (1 0 0) substrates that cause the formation of large SiC nanocrystals named nanoboulders on silicon. Wafer silicon was implanted with varying fluences from 0.38 to 1.14 x 10(17) atoms cm(-2) and subsequently annealed at 1000 degrees C for 15 s. The deuterium induced C-12(d, p)C-13 reaction was used to measure the C-12 dose quantitatively. It was found that the implanted carbon remained in the specimen after annealing. This result, coupled with geometrical analyses of the resulting nanostructures suggest that following nucleation, the SiC nanocrystals grow as a result of C and Si diffusion across the substrate surface, that became oxide free during annealing under vacuum conditions. (c) 2005 Elsevier B.V. All rights reserved.