Method and apparatus for pulling a single crystal

Abstract

Methods and apparatuses for pulling a single crystal. In a conventional method for pulling a single crystal, a neck having a smaller diameter has been formed in order to exclude dislocation induced in dipping a seed crystal into a melt. But in pulling a heavy single crystal having a large diameter of 12 inches or more, the single crystal cannot be supported and falls. When the diameter of the neck is large enough to prevent the fall, the dislocation can not be excluded and propagates to the single crystal. In the present invention, using an apparatus for pulling a single crystal having a laser beam generator or an incoherent light generating-inducing apparatus, the temperature of the front portion of the seed crystal is gradually raised by being irradiated with the laser beam or the incoherent light, and then, the seed crystal is dipped into the melt. As a result, the induction of the dislocation to the seed crystal caused by a thermal stress is prevented. Then, the single crystal is pulled without forming a neck. Therefore, a heavy single crystal can be pulled. The methods and the apparatuses for pulling a single crystal are used for pulling a single crystal ingot such as an upsized silicon single crystal.

Dependencies are inferred from the claim text.