Impurities through the silicon solar cell value chain

It is accepted that impurities impair the electrical properties of silicon materials used in solar cells. Impurities are incorporated into the material along the entire silicon solar cells value chain. In this paper we review the sources and levels of impurities entering the material during the silicon solar cell process steps from silicon production and refining, crystallization, wafering and cell processing. Solar cell processing technology has made giant steps in the last decade and, as the cell architecture becomes more and more sophisticated, a better understanding of the material quality requirements is essential. This paper will review the different process steps by taking into account the latest progresses in cell manufacturing.