Patent ID: 7704318
Filing Date: 2010-04-27
Classification: C30B

Abstract:
1. A method for growing a silicon single crystal, the method comprising: growing a silicon single crystal by the CZ method by using a hot zone structure in which a temperature gradient Gc in a center portion of the crystal is greater than a temperature gradient Ge in a peripheral portion of the crystal, while supplying an inert gas including hydrogen of more than 3 volume % to 8 volume % or less to an interior of a pulling furnace, wherein in accordance with the including of hydrogen of more than 3 volume % to 8 volume % or less, a pulling rate at which a vacancy-dominant region of COP occurrence vanishes over the entire crystal radial direction is shifted toward higher pulling rates than that in the case where hydrogen is not included, and a pulling rate at which an interstitial-silicon-dominant region of dislocation cluster occurrence appears in a portion of the crystal radial direction is shifted toward lower pulling rates than that in the case where hydrogen is not included, thereby, a range of pulling rate at which crystals free of grown-in defects are grown is expanded, wherein the growing of the silicon single crystal is conducted under conditions where the pulling rate at which the vacancy-dominant region of COP occurrence vanishes over the entire crystal radial direction is taken to be an upper limit, and the pulling rate at which the interstitial-silicon-dominant region of dislocation cluster occurrence appears in a portion of the crystal radial direction is taken to be a lower limit, so as to grow the silicon single crystal which is completely free of grown-in defects and does not contain COPs and dislocation clusters over an entire crystal radial direction, and a temperature gradient in an axial direction from a melting point of silicon to 1370° C. is 3.0 to 3.2° C./mm in the center portion of the crystal (Gc), and is from 2.3 to 2.5° C./mm in the peripheral portion (Ge).