基于ScAlN薄膜的高频PMUT阵列的设计与制造  

Design and Fabrication of High-Frequency PMUT Array Based on an ScAlN Thin Film

作　　者：塔桂峰 刘建河[1] 李加东 姚术涛[1,2,3] 刘浩杰 苗斌 商文玲[2,3,4] 陶金燕[2,3,5] TA Guifeng;LIU Jianhe;LI Jiadong;YAO Shutao;LIU Haojie;MIAO Bin;SHANG Wenling;TAO Jinyan(School of Mechanical and Electrical Engineering,Changchun University of Science and Technology,Changchun 130012,China;Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),Chinese Academy of Sciences,Suzhou 215123,China;Key Laboratory of Multifunctional Nanomaterials and Smart Systems,Chinese Academy of Sciences,Suzhou 215123,China;School of Nano-Tech and Nano-Bionics,University of Science and Technology of China,Hefei 230026,China;The College of Science,Shanghai University,Shanghai 200072,China)

机构地区：[1]长春理工大学机电工程学院,吉林长春130012 [2]中国科学院苏州纳米技术与纳米仿生研究所,江苏苏州215123 [3]中国科学院多功能材料与轻巧系统重点实验室,江苏苏州215123 [4]中国科学技术大学纳米技术与纳米仿生学院,安徽合肥230026 [5]上海大学理学院,上海200072

出　　处：《压电与声光》2024年第4期496-504,共9页Piezoelectrics & Acoustooptics

基　　金：苏州市科技计划基金资助项目(SSD2023001);国家自然基金资助项目(62074159);国家重点研发计划基金资助项目(2021YFB3201600)。

摘　　要：高频压电微机械超声换能器(PMUT)应用于各种场景,如指纹识别、无损检测、医疗成像。在当前非侵入式血管成像应用中,存在换能器使用锆钛酸铅压电陶瓷(PZT)及局限于1-D PMUT阵列的问题。设计并制作了一种基于ScAlN材料压电薄膜的2D-PMUT阵列。为了进一步得到阵列最佳的输出性能,降低栅瓣影响,设计了间距为波长的1/2(300μm)的并联六边形阵列,增大了填充因子,降低了阻抗,提高了输出电流。采用SOI晶片作为PMUT的基本结构,设计了微机电系统(MEMS)工艺流程,并完成了晶片制作。通过扫描电子显微镜和聚焦离子束切割确定PMUT的形貌和结构尺寸,并且测得在水中的谐振频率为2.36 MHz。仿真与测试结果表明,测试误差为9.2%,位移灵敏度较好,有望满足非侵入式血管成像应用需求。High-frequency piezoelectric micromechanical ultrasonic transducers(PMUTs) are employed in various applications including fingerprint recognition,non-destructive testing,and medical imaging.In this study,the challenges associated with using lead zirconate titanate piezoelectric ceramics(PZT) in non-invasive vascular imaging and limitations of 1-D PMUT arrays are addressed by designing and fabricating a 2D PMUT array based on ScAlN piezoelectric film.To optimize output performance and minimize gate lobe influence,a parallel-hexagon array is designed with a spacing of half a wavelength(300 μm) to enhance the filling factor,reduce impedance,and improve output current.A silicon-on-insulator(SOI) wafer is utilized as the substrate for the PMUT,facilitating the MEMS process flow and wafer fabrication.The morphology and structure size of the PMUT are characterized using scanning electron microscopy and focused ion beam cutting.The measured resonant frequency in water is 2.36 MHz,with a simulation-test discrepancy of 9.2% and satisfactory displacement sensitivity,suggesting its suitability for non-invasive vascular imaging applications.

关 键 词：高频压电微机械超声换能器阵列(PMUT) ScAlN薄膜 有限元仿真 器件制备 非侵入式血管成像 

分 类 号：TN384[电子电信—物理电子学] TB552[理学—物理]