差分电容式MEMS加速度计的结构设计及仿真  

Structure design and simulation of differential capacitive MEMS accelerometer

作　　者：邬润杰 张伟[1] 郭子龙 WU Runjie;ZHANG Wei;GUO Zilong(Key Laboratory of Sensors,Beijing Information Science&Technology University,Beijing 100101,China;School of Opto-electornical Engineering,Xi’an Technology University,Xi’an 710021,China)

机构地区：[1]北京信息科技大学传感器重点实验室,北京100101 [2]西安工业大学光电工程学院,陕西西安710021

出　　处：《现代电子技术》2023年第13期147-152,共6页Modern Electronics Technique

基　　金：国家自然科学基金资助项目(61372016);北京市教育委员会科技计划重点项目(KZ201711232030);传感器北京市重点实验室开放课题基金资助项目(2022CGKF002)。

摘　　要：为了扩大加速度计的测量范围、提高其灵敏度并且控制成本,提出一种差分电容式MEMS加速度计,并介绍了其敏感机理,即输入加速度时硅质量块产生相应位移,与钯银电极形成差分电容。通过建立输入加速度、电容差及输出电压三者之间的关系,即可检测z轴加速度。使用有限元分析,设置加速度为±100g范围内,对该加速度计支撑梁厚度变化时其应力、位移变化情况进行计算和分析。结果表明,差分电容式MEMS加速度计具有加速度计效应,加速度在±100g范围内线性度良好。加速度计在梁厚为0.058 mm时,输入加速度和位移的最佳比例系数为10-7m/g,其机械灵敏度、位移灵敏度和电容灵敏度较梁厚为0.075 mm时分别提高了10%、38%和37.9%。该研究为后续结构改进、性能优化奠定了理论基础。In order to expand the measuring range,improve the sensitivity and control the cost of the accelerometer,a differential capacitive MEMS accelerometer is proposed,and its sensitive mechanism is introduced,that is,when the acceleration is input,the silicon mass will generate corresponding displacement and form differential capacitance with palladium⁃silver electrode.By establishing the relationship among input acceleration,capacitance difference and output voltage,the z⁃axis acceleration can be detected.By means of the finite element analysis,the stress and displacement changes of the support beam thickness of the accelerometer are calculated and analyzed within the range of±100g of acceleration.The results show that the differential capacitive MEMS accelerometer has the accelerometer effect,with an acceleration range of±100g and good linearity.The optimal ratio coefficient for input acceleration and displacement of the accelerometer is 10-7 m/g when the beam thickness is 0.058 mm.Its mechanical sensitivity,displacement sensitivity,and capacitance sensitivity are increased by 10%,38%,and 37.9%compared to the beam thickness of 0.075 mm,respectively.This study can lay a theoretical foundation for the subsequent structural improvement and performance optimization.

关 键 词：加速度计 敏感元件 “三明治”结构 差分检测 有限元分析 灵敏度 支撑梁厚度 

分 类 号：TN379-34[电子电信—物理电子学] TN212