Evaluation of lifetime degradation caused by oxygen precipitation combined with metal contamination in Cz-Si for solar cells

Lifetime degradation caused by oxygen precipitates combined with metal contamination in Cz-Si for solar cells was evaluated for the samples with different interstitial oxygen concentrations using PL imaging and IR–LST. It was confirmed that phosphorus diffusion gettering is effective for the samples with low oxygen concentration, however the lifetime never recovered for the samples with high oxygen concentration. The enhanced oxygen precipitation process made it more difficult to recover from the metallic contamination. We believe the high density and large size oxygen precipitates are harmful for the lifetime in combination with metal impurities.