Refining of metallurgical silicon for crystalline solar cells

Erwann Fourmond (1) , Cyrille Ndzogha (1) , David Pelletier (1) , Yves Delannoy (1) , Christian Trassy (1) , Y. Caratini (2) , G. Baluais (2) , R. Einhaus (3) , Santo Martinuzzi (4) , Isabelle Perichaud (4)

1 EPM - Elaboration par procédés magnétiques
2 INVENSIL - INVENSIL
3 Apollon Solar - Apollon Solar
4 TECSEN - Laboratoire de thermodynamique, propriétés électriques, contraintes, structures aux échelles nanométriques

A plasma-retining technique is applied to upgraded metallurgical grade silicon (UMG) to produce solar grade silicon for multi-c silicon ingots at direct costs lower than 15€/kg. Using oxygen and hydrogen as reactive gases injected in the plasma, boron is removed from the material mainly in form of BOH and BO. The boron volatili- Zation time has been reduced to 50 min compared to previous processes, by increasing the temperature of the silicon bath. At the same time, the Al, Ca, C, O concentrations are strongly reduced. From a Íirst batch of puritied UMG Silicon, multi-crystalline ingots (l2kg), wafers (125X125mm2) and solar cells have been produced for an evaluation of this intermediate material. The obtained solar cells gave efticiencies of up to ll.7%. Process development towards an up-scaled pilot equipment is on the Way to further increase the puritication efticiency.

Mots clés: Metallurgical-Grade; PV Materials; Silicon purification

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Erwann Fourmond, Cyrille Ndzogha, David Pelletier, Yves Delannoy, Christian Trassy, et al.. Refining of metallurgical silicon for crystalline solar cells. 19th European Photovoltaic Solar Energy Conference, Jun 2004, Paris, France. pp.1017-1020. ⟨hal-00545537⟩