Broadening of the Si-28, Si-29 isotope distribution in the subsurface layers of Si:B single crystals under plastic deformation has been observed by secondary ion mass spectroscopy. The Si-28, Si-29 profiles broaden with increasing dislocation density. Accompanying changes in the (SiO)-Si-29-O-16 profile caused by plastic deformation have been found. The shift of the (SiO)-Si-29-O-16 profile to the crystal bulk correlates well with the Si-29 isotope redistribution. The uphill diffusion or dislocation movement is a possible driving force of Si and SiO redistribution, whereas selectivity of the isotopes in oxidation reaction is provided by singlet-triplet transitions in Si 0 short living pairs. (C) 2015 Elsevier B.V. All rights reserved.