MEMS低频水声电容传感器的设计

摘要

A design of low frequency MEMS capacitance sensor for the purpose of low frequency acoustic signal detection .In order to adapt to the underwater work environment , the sensitive structure of the capacitance sensor be put in silicone oil as a whole,which also can improve the pressure of diaphragm .Six equal holes are placed on diaphragmto reduce the squeeze-film damping for flowsilicone oil .This articleintroduced the working principle of capacitance sensor ,established the sensitive structural model of capacitance sensor ,and determined the parameters and performance index of the capacitance through theoretical analysis and calculation as well as finite element simulation analysis on ANSYS Workbench .C-SOI method is adapted to the technological process of Capacitance sensing element .Sensor film and cavity are defined in SOI wafer and silicon wafer respectively .The reso-nance frequency of this capacitance sensor is 5498.6 Hz,and the sensitivity is -148.4 dB.%针对低频水声信号的探测需求,设计了一种MEMS低频水声电容传感器.为适应水下工作环境,改善振膜的承压性,将电容敏感结构整体置于硅油中,同时在振膜上开设6个对称均匀分布的小孔,以降低硅油压膜阻尼.文中介绍了MEMS低频水声电容传感器的工作原理,通过机械建模结合ANSYS Workbench有限元仿真分析,确定了电容敏感结构的结构参数及性能指标.电容敏感单元采用了C-SOI加工工艺方法,传感器振膜和空腔分别定义在SOI片和硅片上.MEMS低频水声电容传感器的谐振频率为5498.6 Hz,灵敏度为-148.4 dB.