Preparation of <001> Oriented PZT Thin Films and the Applications to Micro Piezoelectric Devices

Abstract

Preparation of <001>oriented Pb(ZrTi)O₃(PZT) thin films and their applications to the micro-piezoelectric devices were investigated. The <001>oriented PZT thin films, which have a composition near the morphotropic phase boundary, were deposited on Pt/MgO and Pt/Ti/Si substrates by rf-magnetron sputtering. Both of these thin films show the excellent piezoelectric properties without a poling treatment. The piezoelectric properties of the PZT thin films were examined on the micro fabricated cantilever structure. The PZT thin films on Pt/MgO have high piezoelectric coefficient d₃₁=100×10^-12m/V, extremely low ε_r=240, and remarkably high electromechanical coupling coefficient k₃₁. The PZT thin films on Pt/Ti/Si have very high d₃₁of 150×10^-12m/V and ε_r=700. The PZT thin films on Pt/Ti/Si were applied to the angular rate sensors with a tuning fork type and the actuators of the ink-jet printer heads with 400 pressure chambers. These PZT thin films are suitable for the use in micro piezoelectric sensors and actuators.