Method for pulling single crystal

摘要

A method capable of securely pulling up a heavy single crystal is described. Using an apparatus comprising a crucible for storing a molten material for a single crystal; a heater for heating the molten material; means for pulling up the single crystal to grow by bringing a seed crystal in contact with the surface of the molten material in the crucible; and a flow-regulating member surrounding the single crystal at the growth area for shielding the heat of radiation and for regulating inert gas flow, the method comprises the following steps of setting the distance between the lower end of the flow-regulating member and the surface of the molten material to be a first distance D1 when the seed crystal comes into contact with the surface of the molten material in said crucible; forming the single crystal at the neck portion; thereafter setting the distance between the lower end of the flow-regulating member and the surface of the molten material to be a second distance D2 where D1 (mm)>D2 (mm); and forming the single crystal at the shoulder portion and subsequently forming the single crystal at the body portion. A dislocation-free single crystal having a heavy weight can be produced with a high crystal quality, and the method is applicable to various operation modes at which the apparatus is operated under various conditions of crystal growth.