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 1mm<super>2</super>. 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.