Specific features of steady-state implantation of crystalline silicon with a molecular oxygen-nitrogen beam: Si L2, 3 x-ray emission spectra

The local electronic structure of 〈111〉 n-silicon single-crystal samples is studied using Si L _{2, 3} x-ray emission spectroscopy. The Si _x O _y N _z system is formed by implanting the samples with an ¹⁶O ₂ ⁺ and ¹⁴N ₂ ⁺ ion molecular beam (the oxygen/nitrogen ratio in the molecular beam is 1:1, the implantation energy is 30 keV, the irradiation fluences vary from 2.0 × 10¹⁷ to 1.5 × 10¹⁸ cm^?2, the samples after the implantation are subjected to rapid thermal annealing in nitrogen at 800°C for 5 min). A comparison of the recorded Si L spectra with the spectra of the reference samples reveals clear correlations between the specific features of the electronic structure of the silicon oxynitride formed upon implantation and the ion fluence. It is shown that the implantation at fluences of 2 × 10¹⁷ and 1 × 10¹⁸ cm^?2 results in the predominant formation of Si₃N₄, whereas the implantation at a fluence of 1.5 × 10¹⁸ cm^?2 leads primarily to the formation of SiO₂ layers in single-crystal silicon. The most probable factors and mechanisms accounting for such implantation of ¹⁶O ₂ ⁺ and ¹⁴N ₂ ⁺ into the samples under study are discussed. The experimental data obtained are compared with ab initio full-potential linearized augmented plane wave calculations of the band structure.