氮化铝双端固支音叉谐振器的结构设计

摘要

The resonant sensors based on aluminum nitride double-ended tuning fork (AlN DETF) have the characteristics of small size,good stability and reliability,and fast response.In order to improve the sensitivity and resolution,it is necessary to analyze the influence of the structure parameters of vibrating beam on the sensitivity and signal power of AlN resonator.The multi-physics model of AlN DETF resonator was established to verify effect of single parameter on the sensitivity by pre-stressed eigenfrequency analysis.The relationships between signal power and length,width of vibrating beam were obtained by post-processing data of simulation results when the thickness remained constant.The results show that relative sensitivity and signal power are growing in opposite directions with the width or the length of the beam.Therefore,there is a design tradeoff between signal power and relative sensitivity of AlN resonator according to process and structure strength.The optimized AlN DETF resonator was simulated,and its sensitivity,signal power and Q value are 56 Hz/μN,6.8 × 10-4 nW and 958,respectively.%基于氮化铝双端固支音叉(AlN DETF)的谐振式传感器具有尺寸小、稳定性和可靠性好、时间响应快等特点.为了提高灵敏度和分辨率,需要分析AlN DETF谐振器的振梁结构参数对灵敏度和信号功率的影响.在有限元仿真软件中建立AlN谐振器的多物理场模型,进行预应力特征频率分析,仿真验证单个振梁结构参数对灵敏度的影响.在振梁厚度保持恒定的情况下,对仿真结果的数据进行后处理,得到信号功率与振梁长度、宽度的关系.结果表明,相对灵敏度、信号功率随振梁长度、宽度的变化趋势相反.因此,需要根据工艺水平和结构强度等因素,综合考虑AlN谐振器的信号功率和相对灵敏度,对两者进行权衡.仿真分析了优化后AlN DETF谐振器的性能,±10 μN范围内的灵敏度为56 Hz/μN,信号功率为6.8×10-4 nW,Q值为958.