| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus for producing a single crystal uniform in quality in the axis direction by a CZ method, and capable of enabling a high-speed pulling up. SOLUTION: This apparatus for producing a single crystal, having a heat insulating board 1 surrounding the growing single crystal 7 and having about 2-6 times thickness at the under part of the heat insulating board 1 as much as that of the conventional one, in combination with an after cooler 21 covering a rim 1a of the heat insulating board 1 and surrounding the single crystal 7 is used as one example of the apparatus and the method for producing the single crystal. The amount of cooling water supplied to the after cooler 21 is gradually increased according to the growing length of the single crystal and after the length of the single crystal reaches a prescribed size, the amount of the cooling water is kept constant. As the result, because the crystallizing temperature gradient at the neighbor of the solid-liquid interface becomes large, the shape of the single crystal becomes stable and further the pulling up rate of the crystal is made constant from the top of the crystal to the bottom thereof. The pulling-up rate is increased so as to be 1.3-2.2 times as fast as the conventional one, and the single crystal having uniform quality in the axis direction can be obtained. |
