Patent ID: 8236265

Claim:
A method for forming high quality silicon material for photovoltaic devices, the method comprising: transferring a raw silicon material in a crucible having an interior region, the crucible being provided within a vessel, the crucible being made of a quartz material, the quartz material being capable of withstanding a temperature of at least 1400° C.; subjecting the raw silicon material in the crucible to thermal energy to cause the raw silicon material to be melted into a liquid state, the melted material having an exposed region bounded by the interior region of the crucible; subjecting an exposed inner region of the melted material to an energy source comprising two or more arc heaters symmetrically configured above the exposed region and spaced by a gap between the exposed region and a muzzle region of each of the two or more arc heaters to cause formation of determined temperature profile within a vicinity of an inner region of the exposed melted material while maintaining outer regions of the melted material at a temperature below a melting point of the quartz material of the crucible, wherein the two or more arc heaters are configured with a focus point below the surface of the melted material; and removing one or more impurities from the melted material to form a higher purity silicon material in the crucible.