Patent ID: 7364618

Claim:
A method for growing silicon single crystals, the method comprising: pulling a silicon single crystal by the CZ method in a hydrogen-containing inert gas atmosphere so as to expand the range of the pull rate for the PI region at which a single crystal containing no COPs or dislocation clusters throughout the crystal in the radial direction thereof and having an interstitial rich region can be pulled, wherein the pulling of the silicon single crystal is conducted at a pull rate within this expanded range of the pull rate for the PI region so as to grow a grown-in defect-free silicon single crystal having a body portion that is an interstitial rich region, and the composition of the hydrogen-containing inert gas atmosphere is set so that the hydrogen concentration VH (vol %), air concentration VAir (vol %) and argon concentration VAr (vol %), when indicated as points (VH, VAr, VAir) in appended FIG. 12 , are values which lie within a non-combustion range-enclosed by point A ( 100 , 0 , 0 ), point B ( 0 , 100 , 0 ), point C ( 0 , 0 , 100 ), point D ( 4 , 0 , 96 ), point B ( 4 , 84 , 12 ) and point F ( 75 , 0 , 25 ).