Research on Capacitive MEMS Microphones Based on Contour Backplate and Slit Diaphragm

Capacitive MEMS microphones have been widely applied in mobile intelligent devices such as hearing aids, consumer electronics, and intelligent driving, owing to their excellent performance and technical advantages including high sensitivity, high reliability, mass-producibility, ease of integration, and feasibility of intelligent implementation. Currently, research on capacitive MEMS microphones focuses on optimizing and enhancing their electroacoustic conversion efficiency and frequency response. Specific research contents include the optimal design of microphone structures as well as the exploration of new principles and materials, aiming to further improve the performance of capacitive MEMS microphones. However, traditional parallel backplate capacitive MEMS microphones face difficulties in balancing the reduction of size and power consumption with the improvement of key performance indicators such as sensitivity and frequency response. To address the existing issues of current capacitive MEMS microphones, this paper designs a slit diaphragm structure that can significantly enhance diaphragm deflection. Combined with a contour backplate, a MEMS microphone structure based on the contour backplate and slit diaphragm is proposed, which can achieve higher sensitivity, higher pull-in voltage, and a flat frequency response range under the same size and lower bias voltage.