Enhanced design of microsystems by combining lumped and distributed system-level models

We highlight the benefits of a tailored system-level modeling approach for the enhanced design of MEMS devices and systems demonstrated for an industrial capacitive silicon microphone. The performance of such microphones is determined by distributed effects like viscous damping and inhomogeneous capacitance variation across the membrane as well as by system-level phenomena like package-induced acoustical effects and the impact of the electronic circuitry for biasing and read-out. In order to meet these antipodal targets, a so-called mixed-level simulation approach is applied, which combines distributed and lumped element models on system-level. This provides maximum insight into the device and system operation while keeping the computational expense low. The presented model enables the investigation of the most relevant figures of merit such as the frequency response, the total harmonic distortion, and the signal-to-noise ratio as well as the analysis of their respective dependence on design parameters. The accuracy of the derived model and its potential for predictive simulation is assured by extensive calibration of each submodel and demonstrated through comparison to measured data.