High aspect ratio micromirrors with large static rotation and piston actuation

Monolithic high aspect ratio silicon micromirror devices were demonstrated with fully isolated vertical comb drives micromachined from the back side and front side of a 50-μm silicon-on-insulator device layer. The devices are suspended by torsional support beams and exhibit bidirectional single-axis rotation, as well as independent up- and down-pistoning actuation. The comb drives are fabricated with initial comb-finger preengagement of up to 10 μm for constant force actuation and have accurately self-aligned comb-fingers. Device 1 with a 30-μm-thick support beam measured static optical beam deflection from -20° to 19° and bidirectional pistoning motion from -7.5 to 8.25 μm. Device 2 utilizes a highly compliant 10-μm-thick support beam and measured static optical beam deflection from -14° to 16° and downward pistoning motion to -12.5 μm, all at <70 V.