Analysis of Tunable Fabry-Perot Filter in Micro Electronics using Squeezed-Film Damping Method

Micro Electro Mechanical Systems (MEMS) are miniature devices comprising of integrated mechanical and electrical components designed to work in concert to sense and report on the physical properties of their immediate or local environment, or, when signaled to do so, to perform some kind of controlled physical interaction or actuation with their immediate or local environment. Some well-known examples of MEMS-enabled functionality in everyday life are airbag deployment in automobiles; motion and orientation detection in smart phones; and blood pressure measurement in IV lines and catheters. The demands for MEMS devices for use in chemical and biological sensor technologies have been increasing over the past few years because of all of its advantages mainly its cost effectiveness and the ability for mass fabrication. MEMS devices operating in the dynamic mode are made to vibrate at or near their resonant frequency. By doing this, sensitive MEMS-based sensors can be fabricated. But the performance of these sensors degrades when there is damping. Due to their small structural size, damping has a great affect on these types of structures. This thesis presents the study of squeeze-film damping effects on MEMS devices namely a Micro cantilever and a Tunable fabry-Perot Filter. To understand how squeeze-film damping affects a Micro cantilever, a time and frequency response analysis is done using a Vibrometer and from this analysis, the quality factor of the structure is measured and then used to determine the damping affecting the beam. For the Tunable Fabry-Perot Filter, a finite element modelling technique is employed using commercial software called Coventor Ware. It is important to know how damping affects a Fabry-Perot Filter because the structural design consists of a mirror setup surrounded by four doubly-clamped beams which are attached to the mirror through supporting arms. Therefore using this software, a 3-dimensional model of the filter is constructed and simulations are run on this model to determine how squeeze-film damping affects the whole structure