Method for growing silicon single crystal and method for manufacturing silicon wafer
View Patent ↗In a method for growing a silicon single crystal, a silicon single crystal is grown by the Czochralski method to have an oxygen concentration of 12×10 17 to 18×10 17 atoms/cm 3 on ASTM-F121 1979. A mixed gas of an inert gas and a gaseous substance containing hydrogen atoms is used as an atmospheric gas for growing the single crystal. A temperature of the silicon single crystal is controlled during the growth of the crystal such that the ratio Gc/Ge of an axial thermal gradient Gc at the central portion of the crystal between its melting point and its temperature of 1350° C. to an axial thermal gradient Ge at the periphery of the crystal between its melting point and its temperature of 1350° C. is 1.1 to 1.4. The axial thermal gradient Gc at the central portion of the crystal is 3.0 to 3.5° C./mm.
1. A method for growing a silicon single crystal having a body portion composed of an oxide precipitation inhibiting region and having an oxygen concentration of 12×10 17 to 18×10 17 atoms/cm 3 on ASTM-F121 1979 by the Czochralski method, comprising:
using a gas containing a gaseous substance containing hydrogen atoms as an atmospheric gas used for growing the single crystal;
controlling a temperature of the silicon single crystal during its growth such that a ratio Gc/Ge of an axial thermal gradient Gc at the central portion of the crystal between a melting point thereof and 1350° C. to an axial thermal gradient Ge at the periphery of the crystal between the melting point thereof and 1350° C. is 1.1 to 1.4, and the axial thermal gradient Gc at the central portion of the crystal is 3.0 to 3.5° C./mm;
setting a hydrogen molecule partial pressure of the gaseous substance containing hydrogen atoms in the atmospheric gas at 160 to 400 Pa;
determining a relationship between V/G ratios and hydrogen concentrations of individual regions of an infrared scattering defect developing region, an OSF developing region, an oxide precipitation promoting region, an oxide precipitation inhibiting region, and a dislocation cluster developing region, thereby determining the allowable range of hydrogen concentration and a pulling rate for growing a silicon single crystal whose body portion is composed of an oxide precipitation inhibiting region; and
setting a pulling rate within the determined allowable range.
2. The method for growing a silicon single crystal according to claim 1 , comprising cooling a side surface of the silicon single crystal during the crystal growth.
3. The method for growing a silicon single crystal according to claim 1 , wherein the oxygen concentration is 13×10 17 to 16×10 17 atoms/cm 3 on ASTM-F121 1979.
4. The method for growing a silicon single crystal according to claim 1 , wherein a time period for passing a temperature range of the silicon single crystal from 1000° C. to 800° C. is from 80 to 180 minutes.
5. A method for manufacturing a silicon wafer having an oxide precipitates density of 1×10 4 to 1×10 6 pieces/cm 2 comprising:
working a body portion of the silicon single crystal grown by the method for growing a silicon single crystal according to claim 1 into the silicon wafer.
6. A silicon wafer manufactured by the method for manufacturing a silicon wafer according to claim 5 .