Effect of impurities on solar cell parameters in intentionally contaminated multicrystalline silicon

Multicrystalline silicon blocks, intentionally contaminated with iron and copper, had been cast and characterized by the twelve German research institutes working together with twelve German companies in the network project SolarFocus. The results of the lifetime measurements, NAA, FTIR analysis, DLTS/MCTS investigations, determination and simulation of the Fei content, solar cell processing, shunt and microscopic investigations are presented in this paper. The combined analysis reveals the influence of the in-diffusion of metal impurities from the crucible as well as the back-diffusion from the top region of the block. Solar cell efficiency is influenced by multiple recombination active defects as well as shunts induced by a high metal contamination