The analytical solution of the wave equation for a piezoelectric layer supported by a substrate is presented. Using the appropriate boundary conditions, the impedance for a piezoelectric layer driven in the thickness axis is derived and expressed in terms of the mechanical, electrical and piezoelectrical properties of the two materials. This solution allows for the extension of the free resonator IEEE impedance techniques and provides a nondestructive method for determining the material parameters of a piezoelectric film with mechanical support. The validity and universality of the model is demonstrated by measurements on composite sol gel PZT coatings within the thickness range of 15-70μm on aluminum substrates of varying thickness, and by simulating the mass loading of a quartz thickness resonator.

Lanthanum-doped or niobium-doped lead zirconate titanate stannate antiferroelectric thin films with the thickness of about 0.4 μm have been prepared from acetic acid-based or 2-methoxyethanol-based sol-gel method. All the films have the maximum polarization larger than 30 μC/cm2 and show zero remanent polarization. By choosing appropriate compositions, we can make the films have “square” hysteresis loops with very sharp phase transition or “slanted” hysteresis loops with very small hysteresis. The properties that are important for decoupling capacitor and microactuator applications are characterized. For decoupling capacitor applications, films having square hysteresis loops with energy storage density of up to 7 J/cm3 can be made, which release more than half of their stored charge in 10 ns with a maximum current density of more than 9400 A/cm2. For microactuator applications, the films can either have a strain level of 0.32% with very small hysteresis or have a strain level of 0.42% with moderate hysteresis.

Crack-free (111) and (100)-textured Pb(Zr0.52Ti0.48)O3 films with thicknesses ranging from 0.25 to 2.5 μm were prepared using a methoxyethanol-based precursor solution, multiple spin-coating and multiple crystallization steps. The thickness dependence of the dielectric, ferroelectric and piezoelectric properties were investigated on both (111) and (100) oriented PZT films. In both cases, the degree of preferred orientation did not change with thickness. It is found that the dielectric constant, remanent polarization and piezoelectric coefficients (d33 and d31) increase with increasing film thickness. The (100)-textured film showed higher dielectric constant but lower remanent polarization relative to (111) textured film. 1 μm was identified to be a critical thickness that marks the change of dielectric, ferroelectric and piezoelectric behaviors as a function of thickness.

The wafer flexure technique has been developed for the rapid measurement (less than 10 minutes) of the d31 coefficient of piezoelectric thin films. The technique is based upon the controlled bending of a clamped silicon substrate coated with a thin piezoelectric film. Flexure of the wafer results in the transfer of biaxial stress from the silicon to the film, and thus the production of an electric charge. The charge produced is used in conjunction with the applied principle stresses to determine the film's transverse piezoelectric coefficient (d31). For this study, the wafer flexure technique was modified from semi-ac operation to a mechanized ac measurement (i.e. electronic pressure oscillation and lock-in charge detection). Modifications made reduce electromagnetic noise and enhance both the resolution and precision of the device. The system was used to characterize the piezoelectric properties of lead zirconate titanate 52/48 thin films between 0.6 and 2.5 μm thick synthesized using a modified sol-gel technique. The transverse piezoelectric constants (d31) of the PZT films were found to range from −60 to −90 pC/N for the 0.6 and 2.5 μm films, respectively. Aging experiments of the d31; coefficients were also conducted and results showed values to be on the order of 4 to 8% per decade.

(001)-oriented heterostructures consisting of LaAlCO3 substrates, SrRuO3 bottom electrodes, and Pb(Mg1/3Nb2/3) O3-PbTiO3 (PMN-PT) piezoelectric actuators were deposited by pulsed laser deposition (PLD). 4-circle x-ray diffraction analysis confirmed the epitaxial growth of each layer. In general, the electrical properties were found to be very sensitive to the processing conditions, in particular, the growth temperature. At growth temperatures below ∼620°C, the temperature dependence of the dielectric constant and the onset of a hysteritic polarization were found to be depressed by as much as 80 °C. When growth temperatures were increased above 660°C, electrical properties with temperature dependencies more consistent with those of single crystals were observed.

This paper presents a new method for the measurement of the longitudinal piezoelectric coefficient of piezoelectric thin films using the direct piezoelectric effect. A uniform uniaxial stress was applied to the piezoelectric thin film by high-pressure gas and the induced charge was collected and measured by a charge integrator. The effective longitudinal piezoelectric coefficient of lead zirconate titanate (PZT) 52/48 thin films made by sol-gel processing was measured by this method. Undoped films typically have d33 values of ∼ 5 pC/N, while poled films have values up to 220 pC/N.

Currently, smart structures utilize both polymeric sensor and PZT-based actuators. The benefit of self-sensing calls for the development of integrated actuator/sensor composites. This paper addresses the development of this new class of smart materials. Porous PZT ceramics were fabricated by several techniques. PVDF was subsequently infiltrated within the controlled porosity PZT. In addition, PVDF or its blends and PZT powders were in-situ processed to generate controlled piezo and mechanical property composites. Both actuating and sensing of this new class of composite materials were studied. The paper presents the processes-structure-property relationship of this new class of piezocomposites.

Piezoelectric thin films are useful for application in microelectromechanical devices. A series of sol-gel derived PZT (lead zirconate titanate) thin films with various Zr/Ti ratios were prepared on platinized substrates. These films were fired to 650C - 700C to crystallize them into single-phase perovskite films, and their piezoelectric properties were measured using optical lever-based instrumentation. Large d33 piezoelectric coefficients up to 400 pm/V were obtained at the morphotropic phase boundary (PZT 53/47), making such films attractive in applications such as thin film transducers, microcanti levers and surface acoustic wave devices.

A series of sol-gel derived PB(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) films, with various PbTiO3 contents, have been prepared on platinized Si wafers. The (l-x)PZN - xPT films fired to 700C became single phase perovskite for x > 0.7. In the PZN-0.1PT films, the films still contain pyrochlore phase at a firing temperature of 850C; the perovskite phase appeared at a firing temperature of 800C. The dielectric constant increased with increasing PT content, with a peak in dielectric constant at x = 0.8. PZN-PT films with x = 0.8 exhibited dielectric constant, dissipation factor, remanent polarization and coercive field values of 600, 0.10, 6 and 45 kV/cm respectively.

Phase transition and related electric properties of La-modified PbTiO3 (PLT) thin films were investigated. Curie temperature of the films decreased and the diffuseness of the phase transition increased with increasing La content. Simultaneously, it was losing a ferroelectricity and pyroelectric properties degraded in La-rich region. This is considered to be due to the increase of a defect in the film by exchanging Pb2+ ions to La3+ ions. Compensation of the defect by the addition of Mn ion improve the ferroelectricity of the PLT and the films showed an extremely large pyroelectric properties.

SrBi2Ta2O9(SBT) films have been prepared by the sol-gel technique on n-Si(100) substrates and nonvolatile memory operation of a metal-ferroelectric-semiconductor field effect transistor (MFSFET) using the SBT/Si structure has been demonstrated. Ploy-crystalline SBT films can be obtained on Si substrates and it is shown by the secondary ion mass spectrometry (SIMS) that the inter-diffusion between SBT and Si is suppressed even though high annealing temperature is required for the SBT film growth. Then the SBT/Si MFSFETs have been fabricated. Drain current - gate voltage characteristics clearly show hysteresis loops due to the ferroelectric nature of the SBT film. It is demonstrated that the drain current can be controlled by the “write” pulse, which was applied before the measurements, even at the same “read” gate voltage. Memory retention characteristics of SBT/Si MFSFETs are also presented.

We report the first demonstration of an enhancement mode n-channel metal -ferroelectric-semiconductor field effect transistor (MFISFET) realized directly on silicon with yttrium oxide as the buffer layer. The capacitance-voltage (C-V) characteristics of Metal Ferroelectric Insulator Silicon (MFIS) structures show hysteresis and the direction of hysteresis corresponds to ferroelectric polarization. The memory window in the C-V characteristics was 2V for an applied voltage of ± 10V. The memory window did not show significant change due to decrease in rate of change of sweep voltage and temperature. The transmission electron microscopy (TEM) analysis confirms the formation of an amorphous oxide layer between silicon and yttrium oxide buffer layer.

MgO thin films were deposited on Si(100) substrate with different temperatures from 500 °C to 800 °C and different e-beam powers from 25W to 100W using e-beam evaporation method. Pb(Zr0.53Ti0.47)O3(PZT) thin films were deposited on MgO/Si(100) substrates with different drying temperatures from 190 °C to 310 °C using sol-gel technique. If there were no buffer layer between the PZT thin film and Si substrate, the peaks corresponding to perovskite PZT phase were not observed. However the buffer layer were inserted between the PZT thin film and Si substrate, it was possible to fabricate perovskite PZT phase. The barrier effects of MgO thin film to the interdiffusion of Pb were investigated by AES study. Optimum thickness of MgO at which PZT/MgO/Si structure shows P-E hysteresis was calculated, and the hysteresis was tested for PZT/MgO/Si structures with different MgO thicknesses.

Ferroelectric Bi4Ti3O12 thin films were grown by atmospheric pressure metal-organic chemical vapor deposition. After rapid thermal annealing (RTA), the films have a (001) preferred orientation, The I-V and C-V characteristics were studied, the resistivity were in the rang of 1010∼1013 ω. cm, at room temperature. The memory window is about 3V. These results snow that The Bi4Ti3O12 films prepared at present work are suitable for making ferroelectric FEFETs memories. By using planar silicon processing, the FEFET devices have been fabricated, which shows clearly memory effect under a applied ±5V gate voltage.

Mn and Sb doped-PZT (PMSZT)/YBa2Cu3O7−y (YBCO) heterostructures have been integrated with YSZ/Si substrates for fabrication of infrared (IR) detector arrays. PMSZT films with good epitaxy on c-oriented YBCO conducting oxide electrodes have been successfully grown by a pulsed laser ablation deposition. The ferroelectric properties of the PMSZT films show good hystersis loops with a coercive field Ec, of 70 kV/cm and a remnant polarization Pr, of 15μC/cm2. I-V curves show that the PMSZT films have high electrical field breakdown strength with values exceeding 400kV/cm. Doping Mn and Sb into PZT has been shown to not only decrease the Curie temperature Tc from 350°C for PZT to 175°C for PMSZT, but also to enhance the IR responsivity of the pyroelectric thin films. PMSZT detectors have a pyroelectric coefficient of 45nC/cm2K at 25°C and 148nC/cm2K at 88°C, and pyroelectric figures of merit, Fv of 15.5 × 10−11 C. cm/J and Fd of 9.5 × 10−9 C. cm/J at 25°C. The measured normalized detectivity D* in the 2.5μm--19.5μm wavelength range varies from 2.5×108cm. Hz1/2/W to 6.0×108cm. Hz1/2/W.

The temperature distribution under periodic thermal excitation and the pyroelectric response of a four-layer system consisting of front and back semi-infinite media, a pyroelectric element, and an intermediate layer are found. Numerical results and approximate expressions are obtained for special cases, such as a detector with an air gap between the pyroelectric layer and the bulk substrate and a detector on a substrate of finite thickness an air environment. The responsivities of detectors with a lead-lanthanum-titanate (PLT) sensing element on either a Si and a SiO2 substrate are calculated as functions of the pyroelectric layer and the underlying layer thicknesses. It is found that the detector with an air gap has a frequency-independent responsivity over a wide frequency range. A correlation is found between the type of frequency response in each frequency region and the corresponding dominant mechanism for heat loss.

A series of Lead lanthanum titanate (Pb1−xLax)TiO3 thin films with different compositions of x = 0 − 0.33 have been grown on fused quartz substrates by metalorganic chemical vapor deposition (MOCVD) and analyzed by a variety of techniques including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman scattering spectroscopy (RSS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) techniques. XPS results confirmed the film composition of (Pb1−x Lax)TiO3 and lanthanum enrichment in top surface layers. XRD indicates a preferred (100) orientation for the films with x values of 0.05–0.17, while the films with x values above 0.32 have randomly distributed orientations. A gradual change in the crystal structure from tetragonal to cubic arrangement with increasing La composition is noted. XPS data also show the variation of Ti-O, Pb-0 and La-0 bonding with the change in the La composition. The stretching vibrations corresponding to these oxygen related bonding are observed by DRIFT at 667, 826, 936 and 529 cm−1 respectively. This combined investigation on epitaxial PLT films may enhance our understanding of the ferroelectric PLT materials.

The lead titanium oxide PbTiO3 (PTO) and High Tc Superconductor YBa2Cu3O7-x (YBCO) capacitor hetero structures have been fabricated by pulsed laser ablation directly on 3C-SiC substrates. X-ray diffraction analysis indicates that both PTO layer and YBCO layer are polycrystalline with a perovskite phase. The zero-field cooling (ZFC) curve of YBCO shows a transition temperature Tc around 60 K with a ΔTc ≈ 10 K in a dc SQUID measurement. The ferroelectric properties of the capacitors were characterized by a RT66A apparatus.

The high permittivity of BaSrTiO3 (BST) gives it the potential to replace discrete “passive” capacitors used in portable and wireless applications with integrated capacitors. Bringing thin film devices directly onto Si and GaAs chips shortens lead length and improves overall circuit Q values by reducing inductance, important at RF frequencies. A metalorganic chemical vapor deposition (MOCVD) process has been developed for this purpose. By modifying the basic BST stoichiometry, we have demonstrated charge storage densities up to 3,000 nF/cm2 with leakages below 10−8 A/cm2 at 3 V, and second order dielectric nonlinearities below 100 ppm/V2. For stoichiometric BST, Q factors are as high as 500 at kHz frequencies, and evidence suggests that low losses can be retained up through the L and S microwave bands (1 -4 GHz) in the modified titanates. These properties make alkaline earth titanate films suitable for use in decoupling and bypass capacitors, as well as switched capacitor filters.

Ferroelectric bismuth titanate (Bi4Ti3O12) thin films with controlled degree of c-orientation were fabricated on Pt/Si substrate by solution spin-casting technique. The degree of c-orientation of the films was characterized by XRD analysis and Raman spectroscopy. Film properties such as dielectric constant, dielectric loss factor, spontaneous polarization, and coercive field varied over the range of (119–87), (0.04–0.015), (8–4 μC/cm2), and (30-20 kV/cm), respectively as the degree of c- orientation of the films increased from 0.3 to 0.85. Values for the pyroelectric coefficient, voltage responsivity, and voltage figure of merit were also evaluated. These properties exhibited strong dependence on the degree of c-orientation of the films and, for highly oriented films, reached values of 9.5 nC/°C. cm2, 62 V/W, and 0.4×10−10 C. cm/J, respectively. The inter-correlation between degree of c-orientation, grain morphology, and pyroelectric properties of the films were explored in this study.