Experimental results for phosphorous reduction in a process to upgrade metallurgical silicon to Solar Grade Silicon

There is a measure of agreement that solar grade silicon (SGS) with impurities in the parts per million (ppmw) can be obtained cost effectively from metallurgical grade silicon (MGSi) and used to yield solar cells with performance comparable to Si made using the standard Siemens process. In this paper we present the rationale for SGS development, as well as preliminary experimental results on the reduction of P to about 2 ppmw by application of a unidirectional solidification (UDS) technique using a small, laboratory size induction furnace. Finally, we discuss the potential quality and cost of solar cells made with this material using this process complemented by B slagging using a specially formulated glass composition.