Study of nonlinear pull-in voltage effects in electrostatic cantilever-based MEMS sensors

This paper presents new investigations to improve dynamic behavior of electrostatic cantilever based MEMS sensors by reducing pull-in voltage nonlinearity. It is believe that pull-in voltage is one of the major factors to generate pull-in force that induces parasitic pull-in frequency as a result the behavior of MEMS sensor become nonlinear. The dynamic behavior of the device is modeled under the pull-in force. The results of numerical simulation of nonlinear model show that pull-in nonlinear force participate to generate an opposite parasitic pull-in frequency. The effect of dielectric on pull-in force and pull-in frequency is analyzed by varying the thickness of dielectric layer at different applied. It is found that increasing the dielectric thickness reduces the pull-in nonlinear factors. Simulink tool is also used to model the schematic of complete electromechanical actuation and sensing of the device. The results show that output current of the device depends on the thickness of dielectric layer.