A 3-D MEMS VOA using translational attenuation mechanism based on piezoelectric PZT thin film actuators

Abstract

A silicon micromirror (5mm x 5mm) with gold coating, actuated by piezoelectric Pb(Zr,Ti)O3 cantilever beams, has been demonstrated for variable optical attenuator (VOA) applications. The device is micromachined from a SOI substrate of 5?m thick Si device layer, with multilayers of Pt/Ti/PZT/Pt/Ti being deposited for use as electrodes. The PZT thin film is deposited by solgel technique and the microstructures are later released from the backside to form a 1x10 array of PZT cantilever arranged in parallel. A piezoelectric constant value of 116pmV-1 was estimated and an attenuation of 40dB was reached when a DC driving voltage of 1V was applied to the top electrodes of all the ten cantilevers while the bottom electrodes are grounded.