Measuring the Quality Factor in MEMS Devices

This paper demonstrates and compares different experimental techniques utilized to estimate the quality factor (Q) and natural frequency from non-contact measurements of Microelectromechanical Systems (MEMS) motions. The relative merits of those techniques are contrasted in Q factor estimation for a cantilever beam MEMS actuator, operated in three configurations: free standing, arc-shaped, and s-shaped. It is found that damping estimation techniques that seek to minimize the deviation between the response of an "assumed" linear oscillator and the measured time-history of the motions are superior to those traditional techniques, such as logarithmic decrement and half-power bandwidth. Further, it is found that Q increases three-fold as the actuator contact with the substrate evolves from a line to an area.