Diffusion of implanted sodium in oxygen-containing silicon

The effect of oxygen on diffusion of sodium implanted into silicon is studied for the first time in the temperature range from 500 to 850oC. A high-resistivity p-Si (ρ > 1 kΩ cm) grown by the Czochralski method in a magnetic field (mCz) with the oxygen concentration ∼3 x 1017 cm-3 was used. For comparison, we used silicon grown by the crucibleless floating zone method (fz). Temperature dependences of the effective diffusion coefficient of sodium in the mCz-Si and fz-Si crystals were determined and written as DmCz[cm2/s] = 1.12exp(-1.64 eV/kT) cm2/s and Dfz[cm2/s] = 0.024exp(-1.29 eV/kT) cm2/s, respectively. It is assumed that larger values of diffusion parameters in oxygen-containing silicon are caused by formation of complex aggregates that contain sodium and oxygen atoms.