System-level modeling and experimental verification for the CMOS MEMS microphone

A MEMS microphone system consists of subsystems such as chamber acoustics, structural dynamics, capacitor electrostatics and read-out circuitry. No matter fabricating the whole system with SoC (system on chip) by CMOS process or with SiP (system in packaging), the capability of system-level modeling is the prerequisite to design a microphone with high performances. Unlike using circuit analogy in published studies, this research builds all subsystems with SIMULINK® platform on a signal-flow base, which promises not only the nonlinear interactions between subsystems but also a deeply physical insight into the design investigation. Compared with experimental measurement, this modeling shows good agreement and can catch important features in frequency response such as circuit-induced low-frequency decaying and packaging-induced Helmholtz's resonance.