SILICON SINGLE CRYSTAL AND METHOD FOR MANUFACTURE THEREOF

摘要

A silicon single crystal manufacturing method includes: applying a transverse magnetic field to a melt of polysilicon with a carbon concentration of at most 1.0×1015 atoms/cm3 as a raw material; rotating the crucible at 5.0 rpm or less; allowing inert gas to flow at rate A (m/sec) of formula (1) at a position 20-50% of Y above the melt surface; controlling the rate A within the range of 0.2 to 5,000/d (m/sec) (d: crystal diameter (mm)); and reducing the total power of side and bottom heaters by 3 to 30% and the side heater power by 5 to 45% until the solidified fraction reaches 30%.;A=[Q·7601000·60·P·α]/[π·X·Y·10-6](1)Q: Inert gas volumetric flow rate (L/min)P: Pressure (Torr) in furnaceX: Radiation shield opening diameterY: Distance (mm) from raw material melt surface to radiation shield lower endα: Correction coefficient

主权项

1. A method for manufacturing a silicon single crystal comprising:
preparing polysilicon with a carbon concentration of at most 1.0×1015 atoms/cm3 as a raw material and melting the raw material charged into a quartz crucible to form a raw material melt; applying a transverse magnetic field to the raw material melt; rotating the quartz crucible charged with the raw material melt at a speed of at most 5.0 rpm when pulling a silicon single crystal by a Czochralski method; allowing an inert gas to flow at a rate A (m/sec) at a position in the range from 20 to 50% of the distance Y from a surface of the raw material melt to a lower end of a radiation shield, wherein the rate A is expressed by formula (1):[MathematicalFormula1]A=[Q·7601000·60·P·α]/[π·X·Y·10-6](1) wherein Q is the flow rate (L/min) of the inert gas, P is the pressure (Torr) in a furnace, X is a diameter (mm) of an opening of a radiation shield, Y is the distance (mm) from the surface of the raw material melt to the lower end of the radiation shield, and a is a correction coefficient; controlling the rate A within the range of 0.2 to 5,000/d (m/sec), wherein d (mm) is a diameter of a body of the pulled crystal, during at least a period from a time when the melting of the raw material is started to a time when the solidified fraction of the pulled crystal reaches 30%; and reducing the total power of a side heater and a bottom heater by a rate of 3 to 30%, and reducing power of the side heater by a rate of 5 to 45%, respectively, during a period from a time when a seed crystal is brought into contact with a the raw material melt to a time when the solidified fraction of the pulled crystal reaches 30%.