Oxygen concentration control manner null of Si molten liquid for monocrystal pulling up

摘要

PURPOSE: To obtain an Si single crystal having a specified oxygen concn. by adjusting the pressure of the atmosphere in contact with a molten Si doped with group V elements. ;CONSTITUTION: The molten Si doped with group V elements is placed in a crucible, and the oxygen concn. C₂ (number of atoms/cm²) on the surface of molten Si is adjusted by the pressure P of the atmosphere in contact with the molten Si based on equation I. In this case, a constant K determined by the kind of the gaseous atmosphere and the doping atm. is 1.00-1.24 in the case of Ne when the doping amt. is ≥1.0×10^-4 atomic %, 0.85-1.05 in the case of Ar, 0.64-0.80 in the case of Kr, 0.42-0.59 in the case of Xe and 0.30-0.38 in the case of Rn. The oxygen concn. is expressed in terms of JEIDA value (3.03). The oxygen concn. is more precisely controlled when the flow velocity V is fetched as a control factor. In this case, the pressure P (Torr) is controlled by the flow velocity V according to equation II, where (f) is determined by the radius of the crucible and is 1.0×10³ to 3.5×10⁵.;COPYRIGHT: (C)1995,JPO