METHOD FOR PULLING SINGLE CRYSTAL COMPOSED OF SILICON FROM MELT CONTAINED IN CRUCIBLE, AND SINGLE CRYSTAL PRODUCED THEREBY

摘要

PPROBLEM TO BE SOLVED: To further reduce the frequency of macroscopic voids in silicon single crystals without influencing the other crystal properties. PSOLUTION: In a method for pulling a silicon single crystal 9 from a melt 11 in a crucible 4, the single crystal 9 is surrounded by a heat shield 2 during pulling, the lower end 3 of the heat shield 2 is located at a predetermined distance h from the melt surface, and the flow 10 of a gas flows downward between the single crystal 9 and the heat shield 2, outward between the lower end 3 of the heat shield 2 and the melt 11, and then upward in the region outside the heat shield 2. The internal diameter DSBHS/SBof the heat shield 2 at its lower end 3 is larger by at least 55 mm than the diameter DSBSC/SBof the single crystal 9, and the radial width BSBHSU/SBof the heat shield 2 at its lower end 3 is not more than 20% of the diameter DSBSC/SBof the single crystal 9. PCOPYRIGHT: (C)2011,JPO&INPIT