基于表面微加工标准工艺的电容式MEMS麦克风

Capacitive MEMS Microphone Based on Standard Process of Surface Micromachining

设计了一种基于微电子机械系统(MEMS)工艺的电容式麦克风的结构,并基于表面微加工工艺制备了MEMS麦克风。为了优化麦克风结构,通过对比现有麦克风的优缺点,在麦克风可动电极的支撑部分设计了带有刻蚀孔的结构。仿真结果表明,该结构可减小空气阻尼、提高麦克风的信噪比和麦克风在低频段的灵敏度。该麦克风结构的制备工艺可标准化,以便代加工。测试结果表明,在偏置电压为0~20 V时,麦克风的静电电容随着偏置电压的增大而增大,并且预计偏置电压达到20 V附近时可动电极与固定电极接触。本研究为MEMS电容式麦克风的结构优化提供了一种可靠的方案。

A structure of capacitive microphone based on microelectromechanical system(MEMS)technology was designed,and the MEMS microphone was fabricated by surface micromachining technology.By comparing the advantages and disadvantages of existing microphones,a structure with etched holes was designed in the support part of the movable electrode of the microphone to optimize the microphone structure.The simulation results show that the structure can reduce the air damping,improve the signal-to-noise ratio of the microphone and the sensitivity of the microphone in the low frequency band.The preparation process of the microphone structure can be standardized,so as to facilitate the processing.The test results show that when the bias voltage is between 0 and 20 V,the electrostatic capacitance of the microphone increases with the increase of the bias voltage,and the movable electrode is expected to contact the fixed electrode when the bias voltage reaches around 20 V.The research provides a reliable scheme for the structural optimization of capacitive MEMS microphones.