坩埚底角形状对提拉法生长同成分铌酸锂晶体的影响  

Impact of Crucible Bottom Shape on the Growth of Congruent Lithium Niobate Crystals by Czochralski Method

作　　者：郝永鑫 秦娟 孙军 杨金凤 李清连[1,2] 黄贵军 许京军 HAO Yongxin;QIN Juan;SUN Jun;YANG Jinfeng;LI Qinglian;HUANG Guijun;XU Jingjun(School of Physics,Nankai University,Tianjin 300071,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;Hangzhou Institute of Optics and Fine Mechanics,Hangzhou 311421,China;Research Center for Crystal Materials,State Key Laboratory of Functional Materials and Devices for Special Environmental Conditions,Xinjiang Key Laboratory of Functional Crystal Materials,Xinjiang Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Urumqi 830011,China)

机构地区：[1]南开大学物理科学学院,天津300071 [2]山西大学极端光学协同创新中心,太原030006 [3]杭州光学精密机械研究所,杭州311421 [4]中国科学院新疆理化技术研究所,晶体材料研究中心,特殊环境条件功能材料与器件全国重点实验室,新疆功能晶体材料重点实验室,乌鲁木齐830011

出　　处：《无机材料学报》2024年第10期1167-1174,共8页Journal of Inorganic Materials

基　　金：国家自然科学基金(61575099)。

摘　　要：铌酸锂晶体集压电、非线性、电光、光折变等效应于一身,同时其物理化学性质稳定,在集成光学领域极具应用潜力。然而,大尺寸铌酸锂晶体生长的热场设计难度大,其中坩埚形状作为热场设计的重要因素,对晶体生长的影响显著。坩埚直径和高度受制于装料量和晶体直径等硬性约束,因此通常通过改变坩埚局部的形状以改善热场。针对坩埚底角形状对大尺寸同成分铌酸锂晶体生长的影响,本研究使用两种底角形状的坩埚进行了四英寸同成分铌酸锂晶体生长实验。通过数值模拟,分析了坩埚底角形状对固液界面附近晶体内和熔体内轴向温度梯度的影响,以及对固液界面下方熔体内温度分布的影响,进而结合晶体生长结果分析了坩埚底角形状对晶体生长的影响。研究表明:坩埚底角形状的变化会引起坩埚侧壁上温差的变化和熔体内温度梯度的变化,并改变熔体自然对流的强弱;与底部斜角坩埚相比,使用底部弧角坩埚时,固液界面附近晶体内和熔体内的轴向温度梯度较大,固液界面下方熔体内的轴向温度梯度较大,自然对流更强。这一研究结果有助于解决晶体生长脊展宽和胞状界面生长等问题。Lithium niobate crystal,combining its piezoelectric,nonlinear,electro-optical,and photorefractive properties,along with its stable physicochemical characteristics,has great potential for applications in integrated optics.However,designing thermal field for large-size lithium niobate crystal growth presents considerable challenges,considering the crucible shape being an important factor that significantly influences the crystal growth in which the diameter and height are compulsively restricted to the factors such as load capacity and crystal diameters.In this study,4-inch congruent lithium niobate crystals were grown by using crucibles with two types of bottom shapes.The impacts of crucible bottom shape on the axial temperature gradient within the crystal and the melt near the crystal-melt interface,and the temperature distribution within the melt below the crystal-melt interface,were analyzed by numerical simulation.The impact of the crucible bottom shape on crystal growth was analyzed in contrast to crystal growth results.It is found that changes in the crucible bottom shape lead to variations in the temperature difference along the crucible sidewall and the temperature gradient within the melt,thereby altering the strength of natural convection in the melt.Compared to crucible with slipped bottom corner,the axial temperature gradient near the crystal-melt interface within the crystal and melt is large when using the crucible with curved bottom corner,and the axial temperature gradient within the melt below the crystal-melt interface is also large,and the natural convection is strong.Therefore,this study helps to solve the problems such as the unwanted crystal growth ridge spreading and the overgrowth of cellular interface.

关 键 词：晶体生长 铌酸锂晶体 坩埚 温度梯度 自然对流 固液界面 

分 类 号：O782[理学—晶体学]