	US 7,456,082 B2
	Method for producing silicon single crystal and silicon single crystal
Keisei Abe, Tokyo (Japan)
Assigned to Sumco Corporation, Tokyo (Japan)
Filed on Jul. 24, 2006, as Appl. No. 11/492,705.
Claims priority of application No. P2005-214236 (JP), filed on Jul. 25, 2005.
Prior Publication US 2007/0028833 A1, Feb. 08, 2007
Int. Cl. H01L 21/30 (2006.01); H01L 21/46 (2006.01)

U.S. Cl. 438—459 [438/48; 438/57; 438/463; 257/E47.003; 257/E43.004; 257/E31.001]

2 Claims

1. A method for producing a silicon single crystal by pulling a silicon single crystal from a silicon melt contained in a crucible, the method comprising:

applying a magnetic field to the silicon melt in a radial direction of the silicon single crystal;

controlling a vertical level of a center of the magnetic field relative to a surface of the silicon melt such that a thermal gradient in an axial direction of the silicon single crystal is maintained at a constant value in respective portions along a radial direction of the silicon single crystal; and

performing a determination of conditions of a magnetic field by:

performing a test pulling of a silicon single crystal while altering a pulling rate within a range of 0.2 mm/minute to 0.6 mm/minute;

growing a first crystal defect region and a second crystal defect region along an axial direction of the silicon single crystal, the first and second crystal defect region respectively having states of crystal defects which are different from each other;

determining the conditions of the magnetic field such that an interface between the first crystal defect region and the second crystal defect region shows a shape satisfying L/D=35/300 to 105/300, where L is a spacing between an axial position of the interface at the center of the crystal and an axial position of the interface at the periphery of the crystal, and D is the diameter of the crystal; and

growing a silicon single crystal while controlling the vertical level of the center of the magnetic field relative to a surface of the silicon melt in accordance with the above-described conditions of the magnetic field.