By R. Einhaus, R&D Director, Apollon Solar; J Kraiem, Apollon Solar; B Drevet, CEA-INES; F Coco, FERROPEM; N Enjalbert, CEA-INES; S Dubois, CEA-INES; D Camel, CEA-INES; D Grosset-Bourbange, FERROPEM; D Pelletier, FERROPEM; T Margaria, FERROPEM
This paper gives an overview of the French PHOTOSIL project that deals with the purification of metallurgical-grade (MG) silicon via different stages of upgraded metallurgical-grade (UMG) silicon to finally arrive at a purity level that is compatible with the requirements of the silicon-based PV industry. However, purified UMG silicon in general and by definition does not reach the ultra-high purity levels of electronic-grade (EG) silicon. Based on the PHOTOSIL project, this paper presents the typical technical challenges and problems encountered with less pure purified UMG silicon and how they were resolved, both during silicon purification and crystallization and the processing of solar cells.
