The peculiarities of a buried layer formation obtained by a co-implantation of O2 ions with the energy of 130 keV and carbon ions within the energy range of 30-50 keV have been investigated. The corresponding ion doses for carbon and oxygen ions were equal to 2∙1016 cm-2 and 1.8∙1017 cm-2, respectively. It has been observed that annealing at 1150°C results in enhanced oxygen diffusion towards the region with a maximum carbon concentration. Analysis of x-ray diffraction patterns and TEM images confirm formation of Si nanoclusters in the SiO2 buried layer. The intensive luminescence with the maximum at 600 nm has been observed in the synthesized structures.