Technical Papers and Presentations

In this paper we present a method to reduce the comb drive gap in micro electro mechanical systems (MEMS) beyond the minimum fabrication feature size. The benefit of reducing the gap space between comb drive fingers is to increase its sensitivity to changes in capacitance due to displacements. The minimum feature size of standard fabrication foundries is 2 microns. To reduce the gap beyond a minimum feature size, we propose that the comb drive fingers be initially disengaged to facilitate the fabrication of gaps without conventional limits. Post-fabrication assembly however required to electrostatically translate the stator to engage the comb fingers. Previously, researchers have investigated using engaged variable finger widths; however, compared to what we propose, the previous method results in a jump in the electrostatic force and non-passive sensing. Through modeling and simulation in COMSOL, we examine various stator translation configurations, and comb drive instability due to the smaller gap size.