| 摘要 |
PURPOSE:To prepare the titled single crystal having uniform diameter and high quality, stably in high reproducibility, by detecting the weight of the single crystal during the pulling operation, calculating the deviation of the diameter, adding the predictor of the invert response component obtained by a compensation circuit to the calculated deviation, and controlling the diameter according to the value. CONSTITUTION:In the pulling of a III-V group compound semiconductor single crystal by Czochralski method, the weight of the single crystal 5 being pulled from the molten liquid 4 heated with the heater 3 in the crucible 3 placed in the vessel 1 is detected by the weight detector 7, the signal from the detector 7 is compared with the base signal from the length signal 8, and the diameter deviation signal is obtained by the differentiator 9. Separately, the pulling operation of the single crystal is stopped temporarily, the changeover switch 14 is turned on to input the change in the heating power of the crucible heater 12, and the invert responce component is simulated by the invert responce compensation filter 13 using the relationship between the power and the weight change of the single crystal 5. The simulated output is added to the signal of the diameter deviation, and the sum is outputted to the regulator 10. The regulation signal wherein the invert responce component is compensated is outputted to the temperature regulator 11 to control the temperature of the molten liquid 4 and the diameter of the single crystal 5. |
