EXTREME VERTICAL DISPLACEMENT, HIGH FORCE, SILICON MICROSTAGE ZIPPER ACTUATORS

Abstract

Large vertical deflection, high force microactuators are desired in MEMS for a variety of applications. This thesis details a novel large-displacement electrostatic "zipper" microactuator capable of achieving hundreds of microns of out-of-plane deflection and delivering high forces, fabricated entirely from SOI (silicon-on-insulator). This technology is novel in its use of SiO2 as both a high quality dielectric and the stressed layer of the bimorph. Geometries are explored analytically, numerically and experimentally to provide the greatest electromechanical output while constraining the device footprint to 1mm2. Device performance was benchmarked against previously established out-of-plane microactuators. We report the first instance of zipper-inspired electrostatic "microstage" actuators whose flat center stage and vertical actuation mode is ideal for carrying and moving a load. Fabricated microstages are capable of achieving out-of-plane deflections up to 1.2 mm, force outputs up to 1 mN, pull-in voltage as low as 20 V, and switching times of 1 ms.