基于钽酸锂薄膜衬底的声表面波谐振器  

Surface Acoustic Wave Resonator Based on Lithium Tantalate Thin Film Substrates

作　　者：杨清瑞 王志超 宋学毅 王昭勋 陈雪娇[1] 张师斌 Yang Qingrui;Wang Zhichao;Song Xueyi;Wang Zhaoxun;Chen Xuejiao;Zhang Shibin(School of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]中国科学院上海微系统与信息技术研究所,上海200050

出　　处：《天津大学学报（自然科学与工程技术版）》2022年第10期1093-1100,共8页Journal of Tianjin University：Science and Technology

基　　金：国家重点研发计划资助项目(2020YFB2008800).

摘　　要：在5G通信时代,声表面波(SAW)滤波器作为射频前端滤波器的一种重要解决方案,面临着频率提升和带宽拓展的双重困难,其性能优劣直接影响整个通信系统的质量.近年来,随着离子切片技术的成熟,压电单晶薄膜技术给SAW滤波器带来了新转机.与传统的42°Y切钽酸锂(LiTaO3)衬底相比,基于离子切片技术的同切型钽酸锂-二氧化硅-硅(42°Y-cut LiTaO3-on-insulator,42-LTOI)衬底能有效提升器件的性能.通过研究基于42-LTOI衬底的SAW谐振器的设计参数与其各性能指标(性能系数、机电耦合系数、寄生模式抑制)之间的关系,可以为进一步设计满足5G通信频段要求的SAW滤波器提供指导.通过理论分析、有限元仿真与实验测试相对比的方法,在谐振器优化设计方面得到以下结论:增加谐振器的电极对数或者电极孔径,能够有效提升器件的性能系数,其中增加电极对数的作用更为明显;在具有相同静态电容的谐振器中,电极孔径与电极对数的比值越小(即谐振器的形状在声波传播方向上越狭长),器件的性能系数越高;谐振器的机电耦合系数随电极周期增加呈现先增大后减小的趋势,在本实验使用的衬底参数下,当电极周期为1.8μm时,具有10.8%的理论最大值;谐振器的寄生模式响应会随电极对数的增加而逐渐增强,采用赝电极结构可以有效抑制寄生响应.In the era of fifth-generation(5G)communication,surface acoustic wave(SAW)filters,as an important solution for radio frequency front-end filters,face two difficulties:frequency increase and bandwidth expansion.Moreover,their performance directly affects the quality of the entire communication system.Recently,with the maturity of ion slicing technology,piezoelectric single-crystal film technology has brought a new turn for SAW filters.Compared with the traditional 42°Y-cut LiTaO3 substrate,the 42°Y-cut LiTaO3-on-insulator(42-LTOI)substrate based on ion slicing technology can effectively improve the performance of devices.Analysis results on the relationship between the parameters of the 42-LTOI SAW resonator and its performance(e.g.,figure of merit,electromechanical coupling coefficient,and spurious mode suppression)can provide support for the further design of SAW filters required for 5G communication frequency bands.Through theoretical analysis,finite element simulation,and experimental test,this study draws the following conclusions on the optimization design of resonators.First,increasing the number of electrode pairs or electrode apertures of the resonator can improve the figure of merit,of which the effect of increasing the number of electrode pairs is evident.Second,in resonators with the same static capacitance,the smaller the ratio of the electrode aperture to the number of electrode pairs,the higher is the figure of merit of the device.Third,the electromechanical coupling coefficient of the resonator increases first and then decreases with the increase in the electrode period.It has a theoretical maximum of 10.8%at the electrode period width of 1.8μm under the substrate parameters used in this experiment.Finally,the spurious mode of the resonator gradually enhances as the number of electrode pairs increases,which can be effectively suppressed by the dummy electrode structure.

关 键 词：钽酸锂薄膜衬底 声表面波谐振器 性能系数 机电耦合系数 寄生模式抑制 

分 类 号：TN384[电子电信—物理电子学]