Using the methods of secondary ion mass spectrometry, elastic peak electron spectroscopy and Auger electron spectroscopy, the elemental and chemical composition of the surface, concentration profiles of the distribution of atoms over the depth of silicon implanted with O2+ ions with energy E0 = 1 keV at a dose of D = 6 × 1016 cm–2 were studied. It was found that oxides and suboxides of Si (SiO2, Si2O and SiO0.5) were formed in the ion-doped layer, and it also contained unbound O and Si atoms. Post-implantation annealing at 850–900 K led to the formation of a stoichiometric SiO2 layer ~25–30 Å thick.