Patent attributes
The invention concerns a silicon designed in particular for making solar cells containing a total of impurities ranging between 100 and 400 ppm, a boron content ranging between 0.5 and 3 ppm, a phosphorus/boron content ratio ranging between 1 and 3, and a content of metal elements ranging between 30 and 300 ppm. The invention also concerns a method for making such a silicon from an oxygen- or chorine-refined metallurgical silicon containing at least 500 ppm of metal elements, and comprising: refusion under neutral atmosphere of the refined silicon, in an electric furnace equipped with a hot crucible; transferring the molten silicon, to provide a plasma refining, in an electric furnace equipped with a hot crucible; plasma refining with as plasma-forming gas a mixture of argon and of at least a gas belonging the group consisting of chlorine, fluorine, HCI and HF; casting under controlled atmosphere in an ingot mold wherein is produced segregated solidification.
