| 摘要 |
PURPOSE:To reduce the generation of a twin crystal and cracks in a single crystal by specifying the temp. gradient on the surface of a specified melt and direction of a seed crystal when the seed crystal is brought into contact with the surface of the melt and then pulled up. CONSTITUTION:The mean temp. gradient of the atmosphere from the surface of a single crystal material melt in a crucible to the height 20mm right above the surface is set to 30-60 deg.C/cm. In addition to such conditions, a long seed crystal is used, and the single crystal is pulled up in the direction <110> within + or -5 deg. from the direction (namely, theta is within 5 deg.). The number of the revolutions and the growth velocity of the crystal are optimized. The shape of the growing single crystal at an interface is controlled so that the interface may be flattened or protruded by <=5mm to the melt side over the whole length while lowering a high-frequency coil, and the generation of bubbles in the single crystal may also be eliminated. |
