PURPOSE: To control the distribution of impurities to a desired level in a growing crystal with a voltage of a specified polarity applied between a crystallized portion of material for semiconductors and liquid portion thereof in the process of crystallization.
CONSTITUTION: A speed crystal 13 is pulled from a molten substance filled in a crucible 11, a molten Si 12 for example, while rotated, to allow a single crystal 14 to grow. Under such a condition, a D.C. power source 15 is conncted between the crystal 13 and the crucilbe 11 to apply a positive bias, 10 v/cm for example, to the crystal 13. With such an arrangement, most of impurities 16 in the molten Si, such as positively ionized phosphorus, are adsorbed by the crucible 11 to check infiltration thereof into the crystal 14. Accordingly, a desired distribution of impurities in the growning crystal can be obtained by adjusting the bias applied to the crystal 13.
INOUE SHIYOUICHI
MIKAMI HITOSHI
