Effect of Electrode Position on the Dynamic Behavior of Electrostatistically Actuated MEMSResonators

Abstract

Electrostatic actuators have major role in many MEMS devices, e.g. sensors, actuators. The amount of applied voltage to an electrostatic micro-actuator has a direct impact on the amplitude of deflection throughout the cantilever , as well as the position of the upper electrode has a direct impact on the natural frequency of the micro-actuator. This research aims to study the amplitude of deflection in a micro-cantilever at different applied voltagesas well as different position of the upper electrode and determine the critical points of the applied voltage (pull-in voltage) for different position of the electrode pad on the cantilever at which the amplitude of deflection exceedone-third(1µm) of the total gap (3µm), Also aims to study the natural frequency for different length of electrode pad that cover the actuator layer. Finite element method, ANSYS was used as a simulation tool. As a result the range of the applied voltage(pull-in voltage) that caused this cantileverreach the critical point for amplitude of deflection is (32mV-89mV) for different positions of the electrode pad as well as the natural frequency decrease related to increase the upper electrode length