Design, Fabrication, and Characteristics of a MEMS Micromirror With Sidewall Electrodes

This paper presents a 2-DOF silicon-on-insulator (SOI) microelectromechanical systems (MEMS) mirror with sidewall (SW) electrodes. The biaxial MEMS mirror with SW is actuated by electrostatic actuators. The dimension of mirror plate is 1000?m × 1000?m, with a thickness of 35 ?m. The analytical modeling, fabrication process, and performance characteristics are described. This paper analyzes the effects of the three-end single crystal serpentine torsion bar width and the bottom and SW electrodes on the performance of the mirror. A new fabrication process based on SOI wafer, hybrid bulk/surface micromachined technology, and a high-aspect-ratio shadow mask is presented. In comparison to previous fabrication processes and the Optical iMEMS process, the process is novel, easily understood, and simple to realize. The measured maximum angular deflection achieved is ±11°(mechanical angle) at a static operating voltage and is ± 21°(mechanical angle) at resonance frequency driving. This mirror is well suited for applications where these characteristics are critical, such as in confocal or endoscopic scanning elements