Patent ID: 7632329

Claim:
A refining method for scrap silicon using an electron beam comprising: (a) a step of selectively preparing lumps of n-type scrap silicon containing a single specific impurity element as a dopant by purchasing lumps of scrap silicon, measuring the electrical resistivity of the purchased lumps of scrap silicon, and selecting from the purchased lumps of scrap silicon lumps of n-type scrap silicon containing only the single specific impurity element as a dopant based on the measured electrical resistivity; (b) a step of crushing the prepared lumps of scrap silicon; (c) a step of placing the crushed silicon into a vacuum vessel; (d) a step of irradiating the crushed silicon which was placed into the vacuum vessel with an electron beam to melt it and vaporize at least a portion of the impurity element, and (e) a step of solidifying the resulting molten silicon.