Efficient model for predictive MEMS microphone design: Model derivation and experimental verification

Abstract

We present a FEM-based, strongly problem-adapted model of a capacitive MEMS microphone that enables a fast and efficient simulation of basic device characteristics (reduction in simulation time from several hours to some minutes). Complex geometrical features (perforation holes, stack of thin material layers with large aspect ratios) as well as couplings between different energy domains have been taken into account by introducing effective or weighted material and stress parameters and easy-to-use semi-analytical, but yet physics-based simplifications. Thus, the model yields accurate results with reference to experimental data obtained from laser Doppler vibrometer measurements. Since the model is parameterized and scales with respect to the most relevant design and material parameters, it provides a proper basis for fast and efficient design and optimization studies.