Review of excitation and detection mechanisms for micromechanical resonators

With the application of silicon resonant sensors in mind, commonly used mechanisms for excitation and detection of transversal vibrations in micro­mechanical silicon structures are modelled and compared. Three types of mechanisms are distinguished: the reversible excitation/ detection mechanisms (the electrostatic mechanism using an air gap, the electrostatic mechanism using a dielec­tric thin film, the piezoelectric mechanism and the magnetic mechanism), the irreversible excitation mechanisms (electro-and optothermal excitation) and the irreversible detection mechanisms (pjezoresistive detection and optical detection techniques). The model is applied to prismatic beams; however, it can easily be used to model other structures, provided that the modes of vibration are known. The method used is highly systematic, which makes comparison of the mechanisms with respect to many aspects possible. In this paper, they are compared in terms of the magnitude of the induced driving forces, the sensitivity of the detection mechanisms, the effect of electrical loads on the quality factor of vibration, elec­tromechanical coupling factors, scaling factors, stabjljty, and the effect of the mechanisms on the resonance frequency.