Pb ZrxTi1 Research Articles

Nanostructural tuning of the texture of PZT pervoskite thin films grown by RF sputtering for piezoelectric MEMS

ABSTRACTCurrently, large efforts are going on to scale up PZT thin film processes for large volume MEMS fabrication. It is critical to complete the scaling up with optimized film properties. In this work we report about microstructural control and piezoelectric properties of RF magnetron sputtered PZT (Pb(Zrx,Ti1−x)O3) thin films. The former is a prerequisite to achieve good properties homogeneously on the entire wafer, and with a good repeatability. We focus on the use of a commercial tool capable to reach a deposition rate of 1nm/sec with a thickness uniformity better than +/-3%. We show particularly how the texture can be chosen between (100) and (111) orientation upon tuning the thickness of a very thin TiO2 seed layer on fully passivated Pt electrodes. The surface morphology as resulting from the various grain shapes is strongly influenced by the self-bias established on the substrate, and by the growth temperature. PZT films with compact grain structure and flat surface reached a transverse piezoelectric coefficient e31,f of -23±1 C/m2 in the actuator mode (converse piezoelectric effect) and a dielectric strength of 0.5MV/cm. Both are remarkable values for un-doped, pure PZT thin films.

Erratum to: Photoinduced effects of ferroelectric domains in PbZr1x Ti x O3 thin films as obtained by using piezoresponse force microscopy

Erratum to: Photoinduced effects of ferroelectric domains in PbZr1x Ti x O3 thin films as obtained by using piezoresponse force microscopy

Crystal Structure Determinations of Zr Rich-PbZr1-x Ti x O3

TOF experiments were carried out at room temperature and high temperature for Zr rich PbZr1-x Ti x O3 powders. The best R-factors were obtained with a mixture of R3c and Cm phases. The composition of the Cm phase monotonically increases towards the MPB. At high temperature in the cubic phase, the ADPs for the Pb atom become smaller when Pb displacements along either <110> or <111> are taken into account. This suggests the possibility of coexistence between a cubic ordered phase and a disordered phase which act as a nucleus for R3c and Cm phases at room temperature.

Anomalies of the pyroelectric and dielectric properties of ferroelectric ceramics of the PbZr1-x Ti x O3 system with 0.06 ≤ x ≤ 0.35 at the R3c↔R3m phase transition

The temperature dependences of the pyroelectric and dielectric properties of ferroelectric ceramics of the PbZr1 − x Ti x O3 binary system with x = 0.06, 0.07, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.35 have been obtained synchronously for each sample in the range of the structural phase transition between the states with the symmetry space groups R3c ↔ R3m. It is established that the temperatures of this phase transition for unpolarized and polarized samples coincide in the range 0.06 ≤ x ≤ 0.15. In this case, the x−T phase diagram, constructed on the basis of the pyroelectric and dielectric data, is in excellent agreement with the X-ray diffraction data on single crystals in this concentration range. The effect of dc electric fields from 5 × 105 V m−1 did not lead to any temperature shifts of the R3c ↔ R3m phase transition for the compositions with 0.06 ≤ x ≤ 0.25.

Ferroelectric PZT Thin Films by Sol-Gel Deposition

Sol-gel spin coating has a low ‘thermal budget’, is cheap compared to vacuum-based techniques and is now routinely used to produce dense, pore-free ferroelectric films. PbZrx Ti(1 − x)O3 (PZT) is utilized in most applications because it has a large remanent polarization, high piezo- and pyroelectric coefficients and optimized electromechanical coupling factors, depending on precise composition. This paper will review some of the principles and applications of PZT films and highlight using transmission electron microscopy some of the basic problems and solutions involved in producing device-quality material on Si-substrates.

Models for the frequency dependence of coercive field and the size dependence of remanent polarization in ferroelectric thin films

Abstract We have confirmed the theory of Ishibashi and Orihara for the frequency dependence of coercive fields in ferroelectric thin films.SrBi2NbTaO9, SrBi2Ta2O9, and PbZr1-x Ti x O3 (PZT) data from DeVilbis et al. reveal a power-law dependence of form Ec (f) = Bfd/α , where d is the dimensionality of domains (ca. unity in uniaxial ferroelectrics such as SBT and SBNT) and α is approximately 6, in agreement with theoretical predictions. Models are also presented for the polarization and fatigue data from NEC of micron-sized thin-film strontium bismuth tantalate capacitors, emphasizing behaviour at unsaturated voltages.