| 摘要 |
PURPOSE:To prevent the leakage of air into the crystal growth chamber, surely, by filling the shaft-sealing part with the same kind of gas as the atmosphere in the chamber, and keeping the pressure of the gas in the sealing part to a level above atmospheric pressure and higher than the pressure in the chamber. CONSTITUTION:The oil seal 14 of the crystal pulling shaft 4 is placed in a chamber 15 filled with the same kind of gas as the atmosphere in the pulling chamber, e.g. Ar. The pressure of Ar is maintained at a level above the atmospheric pressure and higher than the pressure in the pulling chamber, and Ar is supplied to the Ar atmosphere chamber 15 through the gas inlet 16. A part of the Ar is discharged to air through the sufficiently narrow and long gap 17 along the direction of the dotted line A. On the other hand, Ar is leaked through the loosely fastened oil seal 14 along the direction of the dotted line B into the chamber, however, the atmosphere in the pulling chamber is not deteriorated because the Ar atmosphere chamber 15 is also filled with pure Ar. The crucible supporting axis is also constructed in a similar manner. A high quality single crystal can be grown stably by this apparatus. |
