Modeling and Simulation of MEMS Capacitive Displacement Sensors

Abstract

The MEMS (Micro-Electro-Mechanical Systems) or NEMS (Nano-Electro-Mechanical Systems) based tensile testing platform serves the purpose of material characterization and failure behaviors at submicron and nanoscopic scales. In the electrostatic transduction of devices, capacitance and electrostatic-forces are the most critical parameters need to be evaluated for the tensile testing setup. In this work, we model a unit cell of a capacitance-based displacement sensor and actuator using the FEM (Finite Element Modeling) tool ANSYS. We study the change in capacitance with respect to transverse and lateral displacements of the capacitor plates and study the relationship between the attractive electrostatic forces generated by applied voltages. Additionally, the influence of fringe fields on the capacitance of unit cell displacement sensors is also studied. Furthermore, the simulation results obtained from FEM ANSYS are compared with the analytical results.