Patent ID: 7704478

Claim:
A method of refining silicon using an electron beam comprising: introducing silicon to be refined into a vacuum chamber; establishing a first vacuum in the vacuum chamber; irradiating the silicon with an electron beam to form molten silicon; evaporating at least one element selected from a first group of impurity elements having a vapor pressure in a vacuum higher than that of silicon from the molten silicon while irradiating the molten silicon with an electron beam; establishing a second vacuum in the vacuum chamber which is lower than the first vacuum; introducing a compound-forming substance which reacts with at least one element in the molten silicon selected from a second group of impurity elements having a vapor pressure in a vacuum which is of the same order or lower than that of silicon into the vacuum chamber; reacting the compound-forming substance with the at least one element selected from the second group of impurity elements to form a vaporizable compound; and evaporating the vaporizable compound from the molten silicon while irradiating the molten silicon with an electron beam.