Superior Electrostrictive Strain Behavior of Antiferroelectric $({\rm Pb}, {\rm La})({\rm Zr}, {\rm Ti}){\rm O}_{3}$ Thick Film Microcantilevers for MEMS Device Applications

The microcantilevers based on the antiferroelectric (AFE) $({\rm Pb}_{0.97}{\rm La}_{0.02})({\rm Zr}_{0.95}{\rm Ti}_{0.05}){\rm O}_{3}$ (PLZT) thick films were fabricated by bulk silicon micromachining process. The conspicuous electrostrictive strain properties with phase transition of the AFE PLZT films induced by electric field were investigated. The resonant vibration velocity and tip deflection on a 650-$\mu{\rm m}$-long cantilever were up to 6767 mm/s and 45.7 $\mu{\rm m}$, under the square wave excitation with the voltage of 40 V, matched to the AFE-ferroelectric phase transition electric field of 210 kV/cm. The ratio of induced tip displacement and cantilever length per unit voltage $[d(\delta)/L/dV]$ was proposed to show the mutation response ability. In addition, the new AFE PLZT microcantilevers exhibited superior value of 10.77/kV, further higher than the traditional ones. Extensive application requirements for microdevices would be met in various fields of microelectromechanical systems.