Dynamic Non-Linear Behaviour of Torsional Resonators in MEMS

This paper reports the theoretical and experimental characterization of the dynamic behavior of torsional resonators that can be applied to inertial sensors. For the correct operation of the devices it is necessary to model the dynamic behavior of the electrostatically actuated torsional resonators both in the linear and nonlinear range. A complete analytical model is developed in this work including nonlinear terms in the electrostatic stiffness. This provides clear quantitative information about the available linear range of operation and opens the way to exploit the nonlinear range. The model is validated through comparison with experimental data on two 22 µm thick polysilicon resonators having different distances from the underlying electrodes.