籽晶边长对SAPMAC法蓝宝石晶体放肩阶段生长质量的影响

Effect of Seed Crystal Length Upon Sapphire Crystal Growth Quality of the Shoulder Stage in SAPMAC Process

温度场的控制是蓝宝石生长过程关键技术问题。采用有限元方法研究了冷心放肩微量提拉法蓝宝石单晶生长过程中籽晶的边长对晶体生长放肩阶段温度场内温度分布、流场分布和晶体的等效应力分布的影响。结果表明:当籽晶边长为24mm时,放肩阶段熔体的轴径向温度变化平缓,温度场内温度分布均匀,熔体的流动和晶体的热应力均适合晶体的生长。

The control of temperature field during the sapphire crystal growth process of is a key technical problem.The effect of the varied seed crystal lengths on the temperatures distributions,the flow patterns in the melt and the thermal stresses during sapphire crystal growth process is investigated with finite element analyses performed by means of ANSYS.The results indicate that when the seed crystal length is 24 mm,the melt of axial and diameter temperature is gentle,and the melt of axial and diameter temperature distribution is uniform,the flow pattern in the melt and the thermal stresses are suitable during the shouldering stage for growth of the sapphire crystal.