In this work, the POCl₃ diffusion process is optimized for low quality silicon material with respect to conversion efficiency focusing on the feasibility for industrial mass production. Hence, the investigation is restricted to emitter diffusion in a single process step. Also, only emitter profiles that can be contacted in a standard screen printing process are considered. We observe a strong correlation between the carrier lifetime measured after diffusion and the solar cell efficiency. The diffusion temperature is identified as a key parameter for carrier lifetime improvements. A reduction of the diffusion temperature by 60°C improves the conversion efficiency of cells made from low quality silicon wafers by 3% relative.
