Calibrations coefficients for determination of concentrations of vacancy-oxygen-related complexes and oxygen dimer in silicon by means of infrared absorption spectroscopy

Vacancy-oxygen complexes VnOm (n, m ≥ 1) in crystalline silicon are nucleation centers for oxygen precipitates, which are widely used as internal getters in modern technologies of production of silicon-based electronic devices and integrated circuits. For the controllable formation of oxygen precipitates in Si crystals in the technology processes the methods of determination of concentrations of the V_nO_m complexes are required. The aim of the present work was to find values of the calibration coefficients for determination of concentrations of the V_nO_m defects in Si from intensities of infrared (IR) absorption bands associated with the local vibrational modes (LVM) of these complexes. A combined electrical (Hall effect) and optical (IR absorption) study of vacancy-oxygen defects in identical silicon crystals irradiated with 6 MeV electrons was carried out. Based on the analysis of the data obtained, the values of the calibration coefficient for the determination of concentration of the vacancy-oxygen (VO) complex in silicon by the infrared absorption method were established: for measurements at room temperature (RT) – NVO = 8.5 · 10¹⁶ · αVO-RT ^cm–3, in the case of low-temperature (LT, Т ≡ 10 K) measurements – N_VO = 3.5 · 10¹⁶ · αVO-LT ^cm–3, where αVO-RT(LT) are absorption coefficients in maxima of the LVM bands due to the VO complex in the spectra measured at corresponding temperatures. Calibration coefficients for the determination of concentrations of other V_nOm (VO₂, VO₃, VO₄, V₂O and V₃O) complexes and the oxygen dimer (O₂) from an analysis of infrared absorption spectra measured at room temperature have been also determined.