一种压电氮化铝双端固支音叉型微谐振器

Piezoelectric Aluminum Nitride Double-Ended Tuning Fork Microresonator

针对小型化高性能谐振式压力传感器的应用需求,提出一种以压电驱动氮化铝(AlN)双端固支音叉型(DETF)微谐振器为敏感元件的新型压力传感器,并设计加工了其核心元器件.首先,通过理论分析,研究了尺寸参数对谐振器在面内弯曲振动模式下的频率-轴向位移灵敏度及品质因数Q值的影响;同时,讨论了层叠结构和电极驱动方案对谐振器性能的影响,从而确定了谐振器设计参数,进一步采用微机电系统(MEMS)工艺加工了该谐振器并对其性能进行了测试.测试结果表明:在真空度为0.1 Pa的环境下,谐振器的Q值为11039,串联谐振阻抗Rs为6.2 kΩ;在常压环境下,谐振器的Q值为844,R_(s)为44.3 kΩ.两种测试条件下谐振器的性能均优于现有文献报道的同类型谐振器研究结果,为进一步实现高灵敏度、高精度和宽动态响应范围的谐振式压力传感器奠定了良好的基础.最后,采用有限元仿真方法确定了谐振器的频率-轴向位移灵敏度,研究了压力传感器灵敏度与压力敏感隔膜厚度的关系,设计了压力传感器加工流程,从而有望制作出完整的压力传感器芯片.

A novel piezoelectric-based pressure sensor is proposed to meet the need for high-performance miniaturized resonant pressure sensors.A piezoelectric-driven aluminum nitride(AlN)double-ended tuning fork(DETF)microresonator was designed and fabricated as the sensing element for this pressure sensor.A theoretical analysis was conducted to investigate the influence of dimensional parameters on the frequency-axial displacement sensitivity and quality factor(Q)of the resonator operating under in-plane flexural modes.The impact of layered structures and electrode driving schemes on resonator performance was also evaluated,establishing the design parameters for the resonator.Furthermore,the resonator was fabricated using micro-electro-mechanical system(MEMS)processes and subjected to performance testing.Test results reveal that under a vacuum level of 0.1 Pa,the resonator demonstrates a Q value of 11039 and a series resonant impedance(Rs)of 6.2 kΩ.Moreover,at atmospheric pressure,the Q value is 844,with R_(s) being 44.3 kΩ.These performance measurements exceed those documented in the literature under the same testing conditions,laying a foundation for the development of highly sensitive,accurate,and broad-dynamicrange resonant pressure sensors.Finally,the frequency-axial displacement sensitivity of the resonator was determined through finite element simulation method and the relationship between the sensitivity of the pressure sensor and the thickness of the pressure-sensing diaphragm was analyzed.Additionally,a fabrication process for the pressure sensor was designed,offering the prospect of manufacturing a comprehensive pressure sensor chip.