| 摘要 |
PURPOSE:To obtain the title high-quality single crystal by detecting the variations in the weight of the growing crystal at any time to calculate the crystal diameter, and correcting the crystal diameter in accordance with the program preset under the specified conditions during growth to control the form of the shoulder part with good reproducibility. CONSTITUTION:For example, the Nd:YAG single crystal material 2 (the material obtained by doping high-purity Al2O3 and Y2O3 with 0.8at% Nd, weighing the appropriate amts. of both materials, and mixing the materials) is charged in the Ir crucible 1 of the single crystal growth device, an electric power is impressed under the command of a personal computer 5 on a high-frequency coil 3 through a D/A conversion circuit 7, an analog controller 8, and a high-frequency oscillator 9 to melt the material, and then pulling up is started. The variations in the weight and high-frequency power are detected at any time with use of a signal 4 from a load cell or a signal 10 from a vacuum thermocouple 10 to calculate the crystal diameter Di. When the Di does not conform to the equation (alpha is 0-15% of Dx and beta is 0-10% of Dx), Dx is set at Dx=Di, the output of the high-frequency power is controlled while correcting the Dx of the preset program, and the shoulder part is formed to grow a single crystal.
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