| 摘要 |
PURPOSE:To obtain a single crystal having a constant diameter in pulling up the single crystal using two-stage heaters, by controlling the power of the bottom heater to set the temperature of the crucible bottom at a given temperature, and setting the power of the top heater on the basis of the resultant power. CONSTITUTION:A raw material melt 3 is contained in a crucible 1 heated by a heater 2 consisting of the top heater 6 and the bottom heater 7, and a single crystal 5 is pulled up by the Czochralski method. In the process, power (P2) of the bottom heater 7 is controlled by adjusting the temperature of the crucible bottom 10 with an automatic temperature controller (AT). The power (P2) of the bottom heater 7 is input to a computer (C), and a product of the power (P2) multiplied by a set power ratio (Rp') as a set value of the power of the top heater 6 is input to the automatic power controller (AP) to adjust the power (P1) of the top heater 6 at the set value. Thus, the temperature gradient in the crucible 1 can be precisely controlled. |
