Purification of boron-containing silicon, used e.g. in solar cell or semiconductor, involves irradiation with electron beam in vacuum chamber, adding boron-binding substance to melt and stopping irradiation when boron has vaporized

摘要

Process for purifying silicon containing boron using an electron beam comprises irradiation with an electron beam in a vacuum chamber and melting to form molten silicon; adding a substance (I) that forms a boron compound (II), which binds the boron in the molten silicon and forms (II) in the vacuum chamber; and ending irradiation with the electron beam when at least part of (II) has vaporized. An independent claim is also included for apparatus for carrying out such a process comprising a vacuum chamber, a crucible, placed in the vacuum chamber, for melting the silicon containing boron; an electron gun for irradiation and melting; and means of introducing (I) into the vacuum chamber.