提拉法生长平肩同成分铌酸锂晶体的研究  

Flat Shoulder Congruent Lithium Niobate Crystals Grown by the Czochralski Method

作　　者：秦娟 梁丹丹 孙军[1,3] 杨金凤 郝永鑫 李清连 张玲[3,5] 许京军[1,3] QIN Juan;LIANG Dandan;SUN Jun;YANG Jinfeng;HAO Yongxin;LI Qinglian;ZHANG Ling;XU Jingjun(School of Physics,Nankai University,Tianjin 300071,China;Department of General Education,Army Engineering University of People’Liberation Army,Nanjing 211101,China;The MOE Key Laboratory of Weak Light Nonlinear Photonics,Nankai University,Tianjin 300071,China;Henan Key Laboratory of Electronic Ceramic Materials and Application,Henan University of Engineering,Zhengzhou 451191,China;TEDA Applied Physics College,Nankai University,Tianjin 300071,China)

机构地区：[1]南开大学物理科学学院,天津300071 [2]中国人民解放军陆军工程大学基础部,南京211101 [3]南开大学教育部弱光非线性光子学重点实验室,天津300071 [4]河南工程大学河南省电子陶瓷材料及应用重点实验室,郑州451191 [5]南开大学泰达应用物理学院,天津300071

出　　处：《无机材料学报》2023年第8期978-986,共9页Journal of Inorganic Materials

基　　金：National Natural Science Foundation of China(52072183,12134007,61575099);111 Project(B07013)。

摘　　要：提拉法生长的晶体肩部形状普遍为斜肩,但斜肩的肩部质量差且加工难度大,会降低晶体的利用率,生长平肩晶体可以解决该问题。然而,平肩晶体对热场和扩肩工艺要求非常高,扩肩阶段易出现多晶和包裹体缺陷。铌酸锂晶体作为一种多功能晶体材料,在电子技术、光通信技术、激光技术及集成光子学技术等领域得到了广泛应用。本研究以同成分铌酸锂晶体为例,利用数值模拟和实验方法,研究了提拉法生长平肩晶体的热场和扩肩工艺。结果表明:提拉法生长平肩晶体时,放肩阶段结晶前沿的界面形状需保持微凸;反射屏降低(10 mm)可减小结晶前沿的温度梯度,避免肩部生成多晶;扩肩速度以监控为主,微调加热功率保证扩肩趋势,适当增大扩肩初期(ϕ≤30 mm)的速度,降低中后期(ϕ≥35 mm)的扩肩速度,可达到不产生包裹体和缩短放肩周期的目的;采用小幅度(Δt=10 min)微调拉速(Δv=0.2 mm/h)和功率的策略,可实现拉速(0~1.5 mm/h)的快速变化(1.5~2 h)而不影响晶体扩肩趋势和质量。使用优化后的热场和扩肩工艺,获得了系列三英寸平肩同成分铌酸锂晶体,晶体光学均匀性良好。The shoulder of the crystals grown by the Czochralski method is generally inclined,leading to poor quality and difficult processing,which then result in low utilization rate of the grown crystal.Take congruent lithium niobate(CLN)crystal as an example,this study used numerical simulation and experimental method to investigate the thermal field and growth process of flat shoulder crystal growth by the Czochralski method which can well acceptedly overcome the above problems.The result shows that the shape of the solid-liquid interface should be convex toward melt at the stage of shouldering.Temperature gradient near solid-liquid interface can be reduced by lowering the after-heater position(10 mm)to avoid the formation of polycrystalline.Control of the shouldering speed is the main way while control heating power is the accurate way to ensure the trend of shouldering.Accelerating the speed at the initial stage of shouldering(ϕ≤30 mm)and slowdown the speed at the middle and later stage of shouldering(ϕ≥35 mm)can shorten the period of shouldering and avoid defect inclusion.The pulling rate(0-1.5 mm/h)can be changed rapidly(1.5-2 h)without affecting the trend and quality of shouldering by adjusting power with a small amplitude(Δt=10 min,Δv=0.2 mm/h).By using these adjusting ways to thermal field and growth process,a series of 3-inch(1 inch=25.4 mm)flat shoulder CLN crystals with good optical homogeneity have been successfully grown.

关 键 词：铌酸锂 热场设计 平肩晶体 提拉法 晶体生长 

分 类 号：O782[理学—晶体学]