Analytical Model for the Pull-in Time of Low-Q MEMS Devices

L.A. Rocha, E. Cretu and R.F. Wollfenbuttel
Delft University of Technology, NL

Keywords: pull-in, MEMS dynamics, squeeze film damping, large-signal analysis

Abstract:
A meta-stable transient region just beyond pull-in displacement that ultimately governs the pull-in time in critically damped systems is identified in this paper. Since the pull-in displacement time is basically governed by this second region (almost 90% of the pull-in time), the modeling of this region largely determines the reliability of the overall calculation of the pull-in dynamic transition. An analytical model for this region is derived and compared with measurements. The model accuracy, despite its simplicity, makes it a valuable tool for the design of MEMS switches outside vacuum and for sensors based on measuring pull-in time.

Nanotech 2004 Conference Technical Program Abstract