| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To control the oxygen concentration to be uniform and optimum over the whole length of a single crystal and to grow a single crystal free from grown-in defects. <P>SOLUTION: A melt 15 is stored in a crucible 13 accommodated in a chamber 12, 19, and then a single crystal 11 is grown by dipping a seed crystal 22 into the melt 15 and pulling the seed crystal 22. Further, the outer peripheral surface of the single crystal 11 being grown is shielded from the irradiation with radiant heat from a heater 17 by a heat shielding body 28 which is provided at an upper part above the surface of the melt 15 to surround the peripheral surface of the single crystal 11. When the top part of the single crystal 11 is grown, the gap GP between the surface of the melt 15 and the lower end of the heat shielding body 28 is adjusted to 20-60 mm, and when the bottom part of the single crystal 11 is grown, the gap GP is adjusted to 40-80 mm larger than the gap GP during growth of the top part. Thereby, the difference of oxygen concentrations in the top part and the bottom part in the single crystal 11 is controlled to be within±1.0 ppma. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
