蓝宝石热物性能对SAPMAC法晶体生长影响的模拟分析

Numerical Simulation of Thermophysical Performance's Effect on Sapphire Crystal Growth with SAPMAC Method

利用数值模拟计算方法对材料热物性能对晶体生长的影响进行了计算分析,计算表明:晶体与熔体具有相同的热导率时,较小的热导率能够有效降低晶体内温度梯度和界面凸出率;晶体热导率各向异性时,较大的径向热导率,较小的轴向热导率更有利于保持微凸的生长界面;热熔、潜热对温场几乎没有影响。选α轴为结晶取向,成功生长出了直径达230mm、高质量蓝宝石晶体。

Large size sapphire crystal growth with SAPMAC method is achieved by controlling the temperature gradient of system to control the whole growth process, and the values and distribution of temperature gradient in crystal and melt has the important effect on crystal growth. The thermophysical performance of crystal material also has great effect on heat transfer and temperature distribution in crystal and melt. The effect of thermophysical performance of material on crystal growth was simulated. The results show that smaller thermal conductivity can reduce the temperature gradient and interface convexity ratio effectively when the crystal and melt has the same conductivities; the bigger radial conductivity and smaller axial conductivity are convenient for keep the little interface convexity ratio; the effect of thermal capacity and heat of fusion on temperature distribution can be negligible. A high quality sapphire crystal was produced by choosing a axial as the orientation, whose diameter is as long as 230mm.