Effects of bipolar pulse poling on the ferroelectric and piezoelectric properties of tetragonal composition Pb(Zr_0.3,Ti_0.7)O ₃ thin films on microelectromechanical systems microcantilevers

We have investigated the effects of bipolar pulse poling (pulse poling) on the crystal orientation, ferroelectric property and piezoelectric property of Pb(Zr_0.3,Ti_0.7)O₃ (tetra-PZT) thin films integrated on MEMS-based microcantilevers. 1.9-μm-thick tetra-PZT thin films were deposited by the sol- gel technique and fabricated into piezoelectric microcantilevers by a MEMS microfabrication process. We have found that the suitable step for pulse poling in the MEMS microfabrication process is after the completion of all of the processes. We have optimized pulse poling voltage by using the fabricated piezoelectric microcantilevers. The volume fraction of the c-domain and remnant polarization of the tetra-PZT thin films increase with pulse poling voltage, while the piezoelectric constant -d₃₁ reaches its maximum at a pulse poling voltage of 50 V. The maximum piezoelectric constant -d₃₁ is estimated to be 50 pm/V.