ELECTRICALLY-INDUCED STRAINS AND PIEZOELECTRIC PROPERTIES OF THIN-LAYER FERROELECTRICS

The electromechanical properties of sol-gel derived ferroelectric Pb(Z r0.53Ti0.47)O-3 (PZT 53/47) thin-layers deposited on silicon were dete rmined as a function of field strength, measurement frequency and tota l thickness. Both electrically-induced strains (epsilon) and piezoelec tric properties (d(33)) were characterized by interferometry. Dielectr ic spectroscopy and polarization switching (P - E) measurements were d etermined for comparative purposes. An asymmetry between forward and t he reverse bias conditions in the epsilon - E displacements was found for both 5-layer deposited and 9-layer deposited structures. However, no asymmetry was observed in the P - E hysteresis characteristics. In addition, the electrically-induced strains and the piezoelectric respo nse were found to be dependent on measurement frequency. No significan t frequency dependence was observed in the polarization or dielectric responses. The results are discussed in terms of a possible clamping e ffect for polarization switching.