Study of pull-in voltage in MEMS actuators

Micro cantilevers are the basic MEMS structures, which can be used both as sensors and actuators. The actuation principle of micro cantilever is based on the measurement of change in cantilever position as result of applied stimulus. The objective of this work is to study concept of pull-in voltage and how to reduce the same. The proposed work is carried out by using Comsol/Multiphysics softwere which is based on the finite element method (FEM). The model is developed and simulated by selecting electro mechanics as the physics domain in the Comsol/Multiphysics softwere. Voltage is applied to upper cantilever beam and lower contact electrode is made as ground. By increasing common area between cantilever beam and contact electrode, and also by reducing thickness of the cantilever beam, it is tried to reduce the pull-in voltage. The common area between cantilever beam and contact electrode dimension is increased and the pull-in voltage is reduced from 19.7V to 12.1 V. Similarly the thickness of the cantilever beam is decreased from 1μm to 0.25μm in the steps of 0.25 μm then pull-in voltage is reduced from 57V to 7.2V.