Performance and noise analysis of capacitive silicon microphones using tailored system-level simulation

A fully coupled fluidic-electro-mechanical system-level model has been assembled and applied to existing and novel silicon microphone designs. Distributed and non-linear effects like fluidic damping and electrostatic forces and their impact on the overall system performance have been investigated. All relevant contributions like the package-induced acoustical effects and the electronic circuitry for biasing and read-out are included as well. Employing the fluctuation-dissipation theorem to our model we are able to predict and discriminate the noise contribution of single microphone regions in order to suggest design measures for the enhancement of the total signal-to-noise ratio (SNR) of the device. Dedicated calibration and validation of the single submodels by laser-vibrometric measurements assure the accuracy and predictive power of the presented model.