A 3-DOF piezoelectric micro vibratory stage based on bulk-PZT/silicon crab-leg suspensions

This paper reports the simulation, fabrication and characterization of a 3-DOF piezoelectric micro vibratory stage design with large X/Y-tilting and Z-translational motion capabilities. The vibratory stage utilizes four piezoelectric crab-leg suspensions formed of bulk-PZT/Si unimorph beams in a L-shaped layout. FEA simulations are utilized to optimize the PZT/Si thickness ratio and characterize the 3-DOF actuation modes and off-axis coupling. A 3×3-mm² sized stage is fabricated via a process that includes bonding and thinning of bulk-PZT substrates on pre-patterned silicon features and micro-patterning of thick PZT films via wet etching. At ±25 V static excitation, X-tilting and Y-tilting angle ranges are measured as >2.3°, and Z-translational displacement is 42 μm. At resonance, the tilting angle range is 12.2° (~1.77 kHz), and the vertical displacement range is 387 μm (0.93 kHz). The device consumes only 100 μW and <;450 μW during static and resonant operation, respectively.