PRODUCTION METHOD OF SAPPHIRE SINGLE CRYSTAL

• Main Authors: KITAGAWA TAIZO, KOCHIYA TOSHIO
• Format: Patent
• Language: English; Japanese
• Published: 17.11.2016
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

PROBLEM TO BE SOLVED: To provide a production method of a sapphire single crystal by a melt solidification method capable of suppressing generation of a crack in a cooling step.SOLUTION: There is provided a production method of a sapphire single crystal by a melt solidification method. The production method of a sapphire single crystal has, after growing a sapphire single crystal having a columnar shape part with a diameter of D (MM), a cooling step in which a cooling velocity Va(°C/h) in a temperature range of the sapphire single crystal between 500°C or higher and 1,200°C or lower satisfies the following formula 1: Va≤0.00125×D-1.125×D+275...formula 1.SELECTED DRAWING: Figure 3 【課題】融液固化法によるサファイア単結晶の製造方法において、冷却工程におけるクラックの発生を抑制したサファイア単結晶の製造方法を提供することを目的とする。【解決手段】融液固化法によるサファイア単結晶の製造方法であって、直径Ｄ（ｍｍ）の円柱形状部を有するサファイア単結晶を育成した後、前記サファイア単結晶の温度が５００℃以上１２００℃以下の温度域における冷却速度Ｖａ（℃／ｈ）が、以下の式１を満たす冷却工程を有するサファイア単結晶の製造方法。Ｖａ≦０．００１２５×Ｄ２−１．１２５×Ｄ＋２７５・・・式１【選択図】図３