Patent ID: 7628854
Filing Date: 2009-12-08
Classification: C30B

Abstract:
1. A process for producing a silicon single crystal, comprising the steps of bringing a seed crystal into contact with a silicon melt, gradually pulling the seed crystal from the melt so as to form a neck having a tapered portion and a constant diameter portion, then pulling a silicon single crystal; wherein the atmosphere used during neck formation is a hydrogen-containing atmosphere prepared by adding a hydrogen-containing substance to an inert gas which has a concentration of nitrogen as an impurity of not more than 20%; a horizontal magnetic field is applied to the silicon melt by a magnetic field generator, the horizontal magnetic field having a strength set within a range of 2,000 to 4,000 G and a center height relative to the liquid surface of the melt set within a range of −150 to +100 mm; and a cusp magnetic field is applied to the silicon melt by the magnetic field generator, the cusp magnetic field having a strength set within a range of 200 to 1,000 G and a center height relative to the surface of the melt set to be within a range of −100 to +100 mm.