US 7,320,731 B2
Process for growing silicon single crystal and process for producing silicon wafer
Toshiaki Ono, Tokyo (Japan); Wataru Sugimura, Tokyo (Japan); and Masataka Hourai, Tokyo (Japan)
Assigned to Sumco Corporation, Tokyo (Japan)
Filed on Jul. 17, 2006, as Appl. No. 11/488,408.
Claims priority of application No. P2005-208525 (JP), filed on Jul. 19, 2005.
Prior Publication US 2007/0017436 A1, Jan. 25, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. C30B 15/20 (2006.01)
U.S. Cl. 117—20  [117/13; 117/19] 8 Claims
OG exemplary drawing
 
1. A process for growing a silicon single crystal by the Czochralski method characterized by using an atmospheric gas for growing a single crystal which is a hydrogen-containing gas which contains a hydrogen-containing substance, and pulling said silicon single crystal at a pulling rate ranging from a value with which a ratio (a/b) of a diameter (b) of said silicon single crystal and an outer diameter (a) of a ring which consists of an OSF-generating region in the radial direction of said silicon single crystal is not higher than 0.77 to another value with which said OSF-generating region disappears at the center part of the crystal.