| 摘要 |
There is disclosed a method for producing a silicon single crystal which comprises preparing a silicon seed crystal having a sharp tip end, and melting down a part of the silicon seed crystal from a tip end to a position having a predetermined thickness, followed by performing a necking operation to form a tapered necking part and a neck portion, and subsequently pulling a single crystal ingot after increasing a diameter, characterized in that said part to be melted down is a part from a tip end to a position in which a diameter A is 1.1 to 2 times the diameter B of the neck portion to be formed; said necking operation is then performed in such a way that a tapered necking part in the shape of a cone is formed at an early stage thereof by pulling a crystal with gradually decreasing a diameter to a minimum diameter of 5 mm or more, and then a neck portion is formed; and subsequently the single crystal ingot is pulled after being increased in a diameter. There can be provided a method of producing a silicon single crystal ingot which enables growing of single crystal ingot without lowering a rate of success in making a crystal dislocation free in the case that a thick neck is formed, and thereby improves productivity of a heavy silicon single crystal having a large diameter. |
