| 摘要 |
PURPOSE:To obtain a single crystal capable of direct cylindrical grinding even if bending or variation in diameter occurs in the crystal, by adjusting the diameter of a grown crystal while pulling up a seed from a melt of a single crystal raw material to a diameter of specific times based on that of product wafers. CONSTITUTION:A raw material for an oxide single crystal charged into a crucible is melted by high-frequency electric power and a seed is brought into contact therewith to carry out seeding. The resultant seed is then pulled up to grow the oxide single crystal having a given diameter by a given length. After completing the growth, the single crystal is cut off from the melt and cooled. In the process, the diameter of the crystal to be grown is adjusted to 1.05-1.25 times based on that of a product wafer (diameter in cylindrical grinding). Crystal growth is carried out under condition of gentle temperature gradient in parts just on and under the melt without cracking the crystal and occurrence of unground parts in direct cylindrical grinding of the grown crystal is eliminated by this production process even if bending occurs in the grown crystal. Thereby wafers for the crystal are readily obtained in high yield.
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