近化学计量比铌酸锂晶体的孪晶缺陷研究  

Twinning Defects in Near-stoichiometric Lithium Niobate Single Crystals

作　　者：郝永鑫 孙军 杨金凤 赵晨成 刘子琦 李清连[1,2] 许京军 HAO Yongxin;SUN Jun;YANG Jinfeng;ZHAO Chencheng;LIU Ziqi;LI Qingian;XU Jingjun(School of Physics,Nankai University,Tianjin 300071,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;Research Center for Crystal Materials,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]中国科学院新疆理化技术研究所,晶体材料研究中心,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》2025年第2期196-204,共9页Journal of Inorganic Materials

基　　金：国家自然科学基金(61575099);高等学校学科创新引智计划(111计划,B23045)。

摘　　要：铌酸锂(LiNbO_(3),简称LN)晶体因其优良的非线性、电光等效应成为最具应用价值的集成光子学材料之一。与同成分铌酸锂(Congruent Lithium Niobate,CLN)晶体相比,近化学计量比铌酸锂(Near-stoichiometric Lithium Niobate,nSLN)晶体的非线性、电光等性能更加突出,具有更高的应用价值。利用扩散法能够制备组分均匀的实用化nSLN晶体,然而对大尺寸LN晶体进行扩散处理时,极易产生孪晶并导致晶片开裂。针对上述问题,本工作开展了扩散法制备大尺寸nSLN晶体的研究,对扩散后晶片上的孪晶缺陷进行表征,分析了孪晶的产生机制,并通过改进晶片放置方式制备了完整的4英寸(100 nm)和6英寸(153 nm)晶片,最后测试了晶片的组分和透过率。结果表明,晶片组分均不低于49.94%(摩尔分数),接近化学计量比,其透过率在600~3300 nm范围内均高于71%。扩散法制备的Z-cut和X-cut晶片上均出现了孪晶,同时Z-cut晶片上的孪晶两两相交时产生裂纹,而X-cut晶片上并未出现裂纹。分析表明Z-cut和X-cut晶片孪晶面为{0112},该孪晶属于形变孪晶。根据形变孪晶的产生机制,认为富锂原料不均匀形变是产生孪晶的主要驱动力。最终,通过改进扩散处理工艺,抑制了扩散孪晶的产生,提高了4英寸(100 nm)、6英寸(153 nm)nSLN晶片的成品率。Lithium niobate(LN)single crystals have emerged as one of the most valuable materials for integrated photonics materials due to their exceptional properties,including non-linear and electro-optical effects.Compared to congruent lithium niobate(CLN)crystals,near-stoichiometric lithium niobate(nSLN)crystals exhibit more pronounced non-linear and electro-optical properties,offering higher application value.nSLN crystals with high compositional uniformity can be prepared using a vapor transport equilibration method.However,large-size LN single crystals are highly susceptible to twinning defects and wafer cracks during diffusion processing.Here,large size nSLN single crystals were prepared using the vapor transport equilibration method to address the aforementioned defects and cracking.The twinning defects within wafers after diffusion processing were characterized,the mechanisms of twinning formation were analyzed,the wafer placement method to produce complete 4-inch(100 nm)and 6-inch(153 nm)wafers was modified,and the composition and transmittance of wafers were tested.Results indicate that composition of the wafers is at least 49.94%(in mole),approaching stoichiometric ratio,and their transmittance is greater than 71%across the 600-3300 nm range.Both Z-cut and X-cut wafers prepared by vapor transport equilibration method exhibited twinning defects.However,cracks were observed when twinning defects intersected on Z-cut wafers,whereas no cracks were present on X-cut wafers.The twinning planes on both Z-cut and X-cut wafers were depending on{0112},which they were identified as deformation twins.According to the mechanism of deformation twin formation,the non-uniform deformation of lithium-rich materials is identified as the primary driving force beneath the twin formation.Ultimately,it was proposed to mitigate twin activation by modifying the diffusion treatment process,thereby increasing the yields of 4-inch(100 nm)and 6-inch(153 nm)nSLN wafers.

关 键 词：近化学计量比铌酸锂 扩散法 孪晶 富锂气氛 

分 类 号：O782[理学—晶体学]