| 摘要 |
PURPOSE:To uniformize impurity concentration in a crystal with a simple apparatus, by solidifying a major part of a molten liquid containing doping impurity from below, starting the crystal growth from the upper liquid part and melting the solidified polycrystals in a manner to keep the volume of the molten liquid at a definite level. CONSTITUTION:A molten liquid 2 containing impurities is formed in a crucible 1. The molten liquid 2 is slowly solidified from the lower part of the crucible 1 to leave a molten part 4 above the solid or the molten liquid 2 is completely solidified and a part of the upper part of the solidified polycrystals 3 is melted to form a molten part 4. The crystal growth is started from the molten part 4 and the volume of the molten part 4 is maintained at a definite level by controlling a heating means. The impurity concentration in the polycrystals 3 abruptly decreases toward the lower part when the segregation coefficient K is sufficiently smaller than 1. Accordingly, no considerable change in the impurity concentration occurs in the molten part in the course of growing a crystal from the start of crystal growth. A similar crystal having uniform impurity concentration can be produced when the segregation coefficient is larger than 1.
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