Creep behavior of undoped and La-Nb codoped PZT based micro-piezoactuatorsfor micro-optical modulator applications

摘要

Time-dependent deformation (creep) behaviors of piezoelectric microactuators have been investigated.Position (or gap height) drift of microbridged actuator beam and its displacement amplitude change withtime could be attributed to the anelastic behavior of the driving unit itself based on lead zirconate titanate(PZT) in the actuator, and as well as to the mechanical stress states established in the microactuatorbeam after the surface release of the micromachined actuator structure. From creep analyses of a simplemicrocantilever and microbridge beam structures, it was turned out that the overall creep behaviorin microbridged piezoactuator structure was mainly dependent on the actuator beam initial deflectionconfiguration governed both by residual stress of the actuating part Pt/PZT/Pt stack and the stress gradientthrough the silicon nitride (SiNx) microbridge beam.