A low voltage actuated micromirror with an extra vertical electrode for 90 rotation

Abstract

We have proposed a new type of electrostatic actuator for optical switching which has trench structure to make low voltage driving possible. Its lower or fixed electrode consists of a horizontal electrode and an extra vertical one which acts as a stopper for the exact 90° rotation. To fabricate the proposed actuator, a new planarization approach, laminating an organic film on a wafer, has been introduced to make a planar sacrificial layer over the trench. Comparison of theoretical analysis with experimental result has been made for the actuator. We have found that the actuation voltage (47 V) could be reduced up to 50% of that of the conventional one. The rising and falling times were measured to be 5 and 15 ms, respectively. The planarization process can be very effective and powerful for structures with deep trenches or pits.