Determination of low carbon concentration in Czochralski-grown Si crystals for solar cells by luminescence activation using electron irradiation

We attempted the quantification of carbon concentration in Czochralski-grown Si crystals for solar cells by luminescence activation in the concentration range lower than the detection limit of IR absorption spectroscopy. A positive correlation was found between the relative intensity of the C-line and the substitutional carbon (C s ) concentration determined by IR absorption in the low 10 15 cm −3 range. The detection limit was estimated to be approximately 5 × 10 12 cm −3 . We measured and compared the C s concentrations in the wafers sliced from ingots grown under different conditions. The variations in C s concentrations in the respective ingots were consistent with the segregation effect.