Role of Heavily B-doped Layer on Low-Temperature Fe Gettering in Bifacial Si Solar Cell Fabrication

The gettering behaviors of Fe into Si with and without a p + layer are investigated by deep-level transient spectroscopy. The samples contaminated with Fe in a wide concentration range were annealed at 600 °C to induce gettering. The surface-layer gettering behaviors of Fe for the sample without the p + layer strongly depend on the Fe contamination level, in which the surface-layer gettering is not effective for the sample with low-level contamination at a concentration of less than 1 × 10 13 cm -3 but effective for the sample with middle-level contamination at a concentration of (1–5) × 10 13 cm -3 . In contrast, the samples with the p + layer show effective gettering for low- and middle-level contaminations. The gettering mechanisms of Fe in Si without and with the p + layer are discussed in detail.