Toward Sensitivity Enhancement of MEMS Accelerometers Using Mechanical Amplification Mechanism

Abstract

We report on the novel architecture and operational principle of microelectromechanical accelerometers, which may lead to enhanced sensitivity achieved through mechanical amplification of a proof mass displacements. The integrated amplification mechanism serving also as a linear-to-angular motion transformer is realized as an eccentric elastic torsion link that transforms small out-of-plane motion of the proof mass into significantly larger motion of a tilting element whose displacements are sensed to extract acceleration. The design parameters as well as the amplification ratio were elaborated using a lumped model and numerical finite element simulations. The device was fabricated from silicon-on-insulator wafer and is distinguished by a robust single-layer architecture and simple fabrication process. The devices were operated using electrostatic and inertial actuation of the proof mass combined with the optical sensing. Theoretical and experimental results, which are in a good agreement with each other, indicate that the motion amplification scheme realized in the framework of the suggested architecture results in larger detectable displacements and could be efficiently used for sensitivity improvement of microaccelerometers.