SILICON PURIFICATION METHOD

摘要

Disclosed is a silicon purification method that comprises at least a solidification purifying process that removes metal impurities by irradiating an electron beam (EB) on a base material made of metal silicon. In the solidification purifying process, the base material (20a) that is to be purified one time is prepared, a portion of the base material (20a) is loaded in a water-cooled crucible (10), the electron beam is irradiated over the whole area of the loaded portion of the base material (20a) that is disposed in a high vacuum atmosphere to completely melt the portion of the base material (20a), the output of the electron beam (EB) is gradually weakened to gradually solidify the portion of the melted base material (20a) from the bottom of the melt toward the melt surface, solidification is proceeded until the solidified portion reaches a first prescribed proportion of the entire base material (20a), the remainder (20f) of the base material (20a) is then loaded in the water-cooled crucible (10), the electron beam (EB) is irradiated over the entire remainder (20f) of the base material to completely melt the remainder of the base material (20a), the output of the electron beam (EB) is gradually weakened to gradually solidify the molten portion (20d) from the bottom toward the melt surface, solidification is proceeded until the solidified portion reaches a second prescribed proportion of the entire molten portion (20d), and the un-solidified molten portion (20j) is removed.