蓝宝石晶体热性能的各向异性对SAPMAC法晶体生长的影响

采用有限元法对冷心放肩微量提拉法蓝宝石晶体生长过程中晶体内的温度、应力分布进行了模拟计算,结合实验结果讨论了蓝宝石晶体热性能的各向异性对晶体生长的影响。研究结果表明,对于冷心放肩微量提拉蓝宝石晶体生长系统,较大的轴向热导率有利于提高晶体的生长速率和界面稳定性,而稍大的径向热导率则有利于保持微凸的生长界面。晶体内的热应力受径向热膨胀系数的影响显著,随着径向热膨胀系数的增大而增大,最大热应力总是出现在籽晶与新生晶体的界面区域。在实验中选a轴为结晶取向,成功生长出了直径达230mm、高质量蓝宝石晶体。

Effect of Sapphire Thermal Performance Anisotropy on Crystal Growth by SAPMAC Method

Finite element method was adopted to simulate the temperature and stress distribution inside the sapphire single crystal during its growth with SAPMAC method.The effect of anisotropic thermal performance of sapphire on crystal growth was discussed with the experimental results.Researching results showed that bigger axial thermal conductivity was propitious to improve the crystal growth velocity and stabilization of the interface and larger radial thermal conductivity was propitious to keep the slight convexity growing interface for the sapphire crystal growth system with SAPMAC method.Thermal stress inside the crystal was influenced notably by radial thermal expansion coefficient and increased along with it. The largest thermal stress always occurred at the interface of the seed and the newborn crystal.In the experiment,a sapphire crystal with high quality whose diameter is up to 230mm was produced successfully by choosing a axis as the crystallization orientation.