Design and Optimization of Electrostatically Actuated Micromirror

Anna Thomas[1], Juny Thomas[1], Deepika Vijayan[1], K.Govardhan[2]
[1]VIT University, Sensor System Technology, School of Electronics Engineering, Vellore, Tamil Nadu, India
[2]VIT University, MEMS & Sensor Division, School of Electronics Engineering, Vellore, Tamil Nadu, India

The microscopic size of MEMS devices accounts for strong coupling effects which arise between the different physical fields and forces. Micromirrors are essential parts of microswitches in fiber optic network telecommunication. They are usually 1 to 3 mm in size, fabricated from single crystalline silicon and mostly are electrostatically actuated. The objective is to design the micromirror to obtain maximum tilt angle with minimum driving voltage. The tilt angle of the micromirror depends on the driving voltage applied to it and also on the stiffness constant for the various structures of the spring. Optimization in mirror structure including placement of electrodes, beam design and applying substantial bias voltage has been achieved using COMSOL Multiphysics®. The proposed serpentine structure appears better than conventional torsional beam structures.