A novel self-aligned vertical electrostatic combdrives actuator for scanning micromirrors

A novel self-aligned vertical electrostatic combdrives actuator has been developed and demonstrated, which enhances the capabilities and applications of high aspect ratio silicon-on-insulator microelectromechanical systems (SOI-MEMS) by enabling additional independent degrees of freedom of operation: both upward and downward vertical pistoning motion as well as bi-directional rotation. The present method utilizes four aligned masks greatly simplifying the existing SOI-MEMS fabrication methods for manufacturing high performance scanning micromirrors. Results from the micromirror device for the novel vertical combdrives show that a mechanical tilt angle of ±1° at 100 Vdc was achieved for a 450 µm diameter micromirror. The scanning micromirror can scan a large angle 62° at the resonance frequency of 10.46 kHz with a sinusoidal voltage input of 60 V in amplitude.