Recombination behavior of nickel in cast multicrystalline silicon

The electrical properties of cast multicrystalline silicon (mc-Si) contaminated by nickel at different temperatures were investigated by means of scanning electron microscopy and electron-beam-induced current (EBIC). Generally, the recombination activity increased with annealing temperature. In comparison with Czochralski silicon contaminated by nickel, some grain boundaries in nickel-contaminated mc-Si annealed at 500 °C also displayed a strong EBIC contrast of about 10%, which suggests a low concentration of nickel in mc-Si can also precipitate or segregate in the defects and increase the recombination strength of defects. Furthermore, nickel tended to precipitate in some special grain boundaries, especially for the annealing at low temperature following slow cool.