Effects of ferroelectric switching on the piezoelectric small-signal response (d33) and electrostriction (M33) of lead zirconate titanate thin films

The effects of an increasing small signal amplitude on the piezoelectric small-signal response and electrostriction of tetragonal Pb(Zr-x, Ti1-x)O-3 thin films are investigated. The piezoelectric small-signal coefficient d(33), piezoelectric large signal-strain S, and electrostriction coefficient M-33 are measured using a double-beam laser interferometer. A continuously increasing influence of the small signal amplitude is found starting at very low values. In particular, the impact on the measured coercive field E-c is found to be stronger than the impact of the cycling frequency of the applied bias field. Also, unexpected electrostrictive behavior is investigated and explained by the influence of ferroelectric switching on the intrinsic piezoelectric lattice strain. Furthermore, the influence of an applied small-signal on the piezoelectric large-signal response is investigated. (C) 2004 American Institute of Physics

Electromechanical properties of lanthanum-doped lead hafnate titanate thin films for integrated piezoelectric MEMS applications

This paper focuses on the deposition and electromechanical characterization of lanthanum-doped lead hafnate titanate (PLHT) thin films as key material in piezoelectric microelectromechanical systems (pMEMS). PLHT (x/30/70) and PLHT(x/45/55) films with a thickness between 150 nm and 250 nm were deposited by chemical solution deposition (CSD). Thereby x varies between 0 and 10% La content. The electrical characterization shows that undoped (x=0) PLHT exhibit ferroelectric behavior similar to PZT of the same composition. La doping results in reduced ferroelectric properties and also affects the electromechanical properties. Measurements using a double beam laser interferometer yield a piezoelectric coefficient d (33) of 60 pm/V, which stays constant with an increasing electric field. This leads to a linear displacement compared to undoped PLHT or conventional PZT films used for MEMS applications

Effects of ferroelectric fatigue on the piezoelectric properties (d33) of tetragonal lead zirconate titanate thin films

The fatigue of the electromechanical properties of tetragonal PbZrx, Ti1-xO3 thin films is investigated. The decrease of electromechanical small-signal response is compared to the fatigue of the electric properties and examined in detail. Property fatigue is attributed mainly to switching-failure of the unit cells. (C) 2005 American Institute of Physics