We report the preparation and characterization of Bi2VO5.5(BVO) films grown on SrTiO3, Pt/SiO2/Si, and n-Si(100) substrates by the MOD technique. Since a dielectric constant of BVO is much lower than that of PZT or SBT, BVO is one of the promising candidates for metal-ferroelectric-semiconductor field-effect transistors (MFSFETs). It is found by X-ray diffraction (XRD) measurements that highly (001)-oriented BVO films were obtained and that the crystalline quality was improved with increasing the annealing temperature. The full width at half maximum (FWHM) in the X-ray rocking curve measurements for BVO films on SrTiO3, Pt/SiO2/Si, and n-Si(100) substrates are 0.60, 1.00, and 5.10, respectively. Electrical properties were measured with Pt top electrodes and the typical relative dielectric constant determined by the C-V characteristics is 60-80.

Simultaneous addition of Al and N to Ta-O thin films is found to significantly improve the dielectric properties of the films. Specifically, substitution of 10-40 at. % Al for Ta along with ∼2 at. % N for O is found to decrease the density of catastrophic defects in the films, resulting in high and statistically more uniform breakdown voltages. This conclusion is based on evaluation of ∼750 individual capacitors in each experiment.

New Hf-Sn-Ti-O thin-film dielectric materials were explored using a compositional-spread approach. Thin films of composition Hf0.2Sn0.05Ti0.75O2 prepared at 250°C have excellent dielectric properties: 40-50 nm thick films with a dielectric constant of 40-60 were obtained, depending on the processing conditions, yielding a specific capacitance of 9-17 fF/µm2. Breakdown fields were measured to be about 4 MV/cm, yielding a Figure of Merit εε0Ebr=19 µC/cm2. Leakage currents, measured at 1 MV/cm, were in the range 10−7- 10−6 A/cm2. Film properties are strongly dependent on substrate temperature during deposition. Like their recently reported zirconium analogs, these materials are of interest for use in Si-IC device technology, for example as storage capacitors in DRAM.

A new type of Pb(Mgl1/3Nb2/3)O3 (PMN) based thin film decoupling capacitor for high speed digital circuits is presented. The thin film capacitor fabricated on a ceramic Al2O3 substrate with Ball Grid Array (BGA) terminations showed low impedance and low inductance characteristics in the 100MHz – 1GHz range. The sol-gel derived Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT) thin film showed a high dielectric constant (k=3000) with broad temperature dependence. The capacitor consists of a PMN-PT thin film (0.8 µm thickness), Au electrodes, and solder balls mounted on the upper electrode as terminals. Numerical simulations based on the Partial Element Equivalent Circuit (PEEC) model were conducted for the design of electrodes, which gives low inductance of the capacitor. It was shown that the thin film 1.2mm × 1.2mm capacitor mounted on a board exhibits high capacitance of 20 nF, low ESR of 100 mΩ, and low inductance of 135 pH. These values are in good agreement with the results of numerical simulations.

One transistor memory devices have been proposed recently. To meet the needs of one transistor memory applications, C-axis oriented Pb5Ge3O11 (PGO) thin films were prepared using metalorganic chemical vapor deposition (MOCVD) and rapid thermal processing (RTP). It was found that the nucleation of C-axis Pb5Ge3O11 phase started at a deposition temperature below 400°C and grain growth dominated at 500°C or above. With increasing annealing temperature, the remanent polarization (Pr) and coercive field (Ec) values increased, and the hysteresis loops of the Pb5Ge3O11 films were well saturated and symmetrical after the post-annealing. The C-axis PGO thin film showed good ferroelectric properties at 5V: 2Pr and 2Ec values were 2.0 - 4.0 µC/cm2 and 90 - 110 kV/cm, respectively. The films also showed excellent fatigue characteristics: no fatigue was observed up to 1 × 109 switching cycles. The retention and imprint properties have also been studied. The leakage currents of the PGO films were 2 - 5 × 10−7 A/cm2 at 100 kV/cm and dielectric constants were 40 - 70. The high quality MOCVD Pb5Ge3O11 films can be used for single transistor ferroelectric memory devices.

A ferroelectric YMnO3 thin films are grown on Si (111) substrates using Y2O3 buffer layers by molecular beam epitaxy (MBE). In-situ reflection high-energy electron diffraction (RHEED) analyses show that both Y2O3 and YMnO3 films are epitaxially grown on Si substrates. X-ray rocking curve measurements also show that the best FWHM (full width at half maximum) values for Y2O3 and YMnO3 films are 0.40° and 0.8°, respectively. C-V characteristics of Al/YMnO3/Y2O3/Si structures indicate the ferroelectric properties of YMnO3 films with a memory window of 0.7V.

Fully epitaxial Pb (Zr,Ti)O3(PZT)/MgO/Si(001) stacked structures, one of the potential components of ferroelectric-gate FETs, have been fabricated and characterized. According to the structural and electrical characterization of MgO/Si structures, epitaxially grown MgO thin films on the Si substrates showed a small leakage current of ∼ 10−8 A/cm2 at the electric field of 1 MV/cm. In the C-V measurements of the as-grown MgO/Si heteroepitaxial interfaces, injection-type hysteresis was observed because of the crystal defects in the MgO film adjacent to the interface. Using oxygen annealing with a temperature of 400 °C, it showed no hysteresis and a lower interface trap density of the order of 1011 cm−2eV−1 could be achieved with no formation of a low dielectric layer at the MgO/Si interface. These results indicate that the epitaxial MgO thin films are applicable as the gate insulators of FETs. After the PZT film was deposited on the MgO/Si structure, the C-V characteristic of the stacked structure showed a ferroelectric hysteresis curve and the low interface trap density of 5 × 1011 cm−2eV−1 A maximum memory window width of 1.2 V could be obtained in the PZT thin film on the Si substrate with a MgO intermediate layer.

Piezoelectric devices generally require film thicknesses in the range 2-200µm and have a response which is perturbed by the substrate. Sol gel and sol gel composite technology provide a manufacturable process for many purposes with a piezoelectric coupling coefficient for 40ptm thick PZT approaching kt= 0.34. Techniques such as laser machining or micromolding are required for patterning thick devices. Measurement and applications of piezoelectric coatings in medical imaging, high temperature ultrasonics and flexure devices are discussed.

This study proposes an improvement of the free vibrating beam method allowing characterization of the d31 coefficients of piezoelectric thin films. Preparation and piezoelectric characterization of PZT thin films are shown. An analytical model of the beam and the thin film is developed. Finite element modeling allows for definition of the validity conditions of the model. A numerical fitting of the model to the experimental values exhibits an excellent overlap. We obtain d31 values from 10 pC/N to 14 pC/N. Advantages of this method are shown compared to the first maximum voltage method.

An atomic force microscope (AFM) is used to measure the magnitude of the effective longitudinal piezoelectric constant (d33) of thin films. Measurements are performed with a conducting diamond AFM tip in contact with a top electrode which is driven by an externally applied voltage. The interaction between the tip and electric field present is a potentially large source of error that is eliminated through the use of this configuration and the conducting diamond tips. Measurements yielded reasonable piezoelectric constants of X-cut single crystal quartz, thin film ZnO, Pb(Zr,Ti)O3 (Zr/Ti = 30/70), and nonpiezoelectric amorphous SiO2 thin films. The system was also used to measure d33 hysteresis loops for Pb(Zrx,Ti1−x)O3 thin films.

Piezoelectric properties of Pb(Zr,Ti)O3 (PZT) and PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT) films are investigated by interferometric technique combined with conventional dielectric and polarization measurements. It is shown that the piezoelectric d33 coefficient of both materials can be expressed based on their polarization and dielectric constant values using an equation for the electrostriction biased by the polarization. The obtained values of electrostriction coefficients are nearly field-independent and significantly smaller than in bulk materials of the same composition. Polarization offset is observed in PZT films subjected to bipolar fatigue, UV illumination and poling at high temperature, and is explained based on the pinning of ferroelectric domains in preferred orientations. The piezoelectric properties of rhombohedral PZT films are found to depend on their texture. The highest piezoelectric coefficient is observed in (100) oriented films, which have smaller polarization as compared to films having (111) preferred orientation. This difference is explained by the different values of electrostriction coefficients in materials with different textures.

Motion detectors consisting of Pb(ZrxTi(1−x))O3 (PZT) thin films, between platinum electrodes, on micromachined silicon compound clamped-clamped or cantilever beam structures were fabricated using either hot KOH or High Aspect Ratio Silicon Etching (HARSE) to micromnachine the silicon. The beams were designed such that a thicker region served as a test mass that produced stress at the top of the membrane springs that supported it when the object to which the detector was mounted moved. The PZT film devices were placed on these membranes to generate a charge, or a voltage, in response to the stress through the piezoelectric effect. Issues of integration of the PZT device fabrication process with the two etching processes are discussed. The effects of PZT composition and device geometry on the response of the detectors to motion is reported and discussed.

Thick films of piezoelectric materials have been grown by pulsed laser deposition (PLD) for use in the development of a programmable micro-fluidic controller. ZnO and BaTiO3 (BTO) films were deposited onto various substrates, including Au/Cr coated Si, Pt/Ti coated Si, and Au/Pd coated glass microchannel plates, at substrate temperatures from room temperature to 800 °C in a background pressure of O2 from 3 to 350 mTorr. ZnO films (∼5 µm thick) were single phase and (001) oriented. BTO films, 33 µm thick, on Pt/Ti/Si were single phase and polycrystalline. To fabricate piezoelectric acoustic transducer, an array of 2 × 4 gold electrodes was deposited onto the thick BTO films through a shadow mask by PLD. The transducers were attached to a simple fluidic circuit with a 1.6 × 1.6 mm cross section and used to generate a flow velocity of 1 mm/s at an operating frequency of 50 MHz.

Pulsed Laser Deposition was used to grow Pb(Mg1/3Nb2/3)O3 (PMN) thin film planar capacitor structures. PMN crystallography was verified by x-ray diffraction and plan-view Transmission Electron Microscopy (TEM). Capacitance of the thin film structures was measured as a function of temperature and frequency. Leakage current was also measured for each capacitor. A DC field was subsequently applied and crystallographic strain was monitored in-situ by X-ray diffraction. The electromechanical strain was found to strongly depend on the deposition conditions for each capacitor. Tensile strains of ∼0.2% and compressive strains of ∼0.3% parallel to the applied field were measured for capacitors of different oxygen contents and thicknesses. We propose that the compressive strain is caused by the combined effect of joule heating of the capacitor structure, caused by large leakage currents, and epitaxial coupling between substrate and films. Electrostrictive tensile strains are of the same order as observed inbulk.

Lithium tantalate (LiTaO3)/PZT ceramic films with thickness above 50 µm have been deposited on stainless steel substrates using a modified sol-gel process. LT powders are dispersed in a PZT sol-gel matrix to form 0-3 ceramic/ceramic composites. The dielectric and impedance response of the LiTaO3/PZT films supported by the substrates has been studied. The pulse echo response of the films as ultrasonic transducers demonstrates a broadband frequency response. The transducers can operate at least up to a temperature of 368°C.

The effect of high energy electron irradiation is investigated on poly(vinylidene fluoridetrifluoroethylene), P(VDF-TrFE), copolymers in the broad range of irradiation doses and temperature. It was found that after a suitable electron irradiation condition, ferroelectric polymer materials show exceptionally high electrostrictive response (> 4%), high dielectric constant (>60) with low dielectric loss over a broad temperature range. In addition, the material after irradiation exhibits many features resembling those of a relaxor ferroelectric, suggesting that the electron irradiation breaks up the coherent polarization domain in a normal ferroelectric material into micro-polar regions that transform the material into a relaxor ferroelectric. These distinct features make this material very attractive for a broad range of applications. In this paper we will review the experimental results on various characteristics of material properties including the dielectric and electrostrictive strain response induced at different temperatures under different electron irradiation conditions and their relation with structural changes observed by X-ray and DSC.

A monolithic thin film structure for uncooled pyroelectric infrared detector arrays was developed to integrate thermally isolated Pb(Zr,Ti)O3-based thin films on silicon, with a low thermal conductivity, aerogel thin film interlayer. Aerogel thin films of 0.4-1.2μm thickness and 70-85% porosity were deposited on silicon substrates by dip coating to form a thermal isolation layer. 200-400nm thick Pb(Zr0.4Ti0.6)O3 films deposited on (La,Sr)CoO3[LSCO]//Pt electrodes atop these aerogel films displayed a remanent polarization Pr = 28μ C/cm2, pyroelectric coefficient p = 30 nC/cm2K, and calculated noise equivalent temperature difference NETD = 0.07°C. Processing of Pb(Zr,Ti)O3 thin films atop the aerogel interlayer structure required modifications to deposition and heat treatment methods to minimize tensile stress accumulation. Effects of thermal processing and thin film stress state on ferroelectric properties are also reported.

Superconducting transition edge bolometers have been fabricated on Ag-doped and undoped YBCO layers on Si(100) substrates using a YSZ buffer layer. We have also fabricated bolometer devices using a stacked-structure of undoped and Ag-doped YBCO material. These thin films were deposited using pulsed laser deposition (PLD). These devices were fabricated using a novel photolithographic/anti-reflective coating (ARC) process. The use of the anti-reflective coating shows no degradation in the overall quality of the superconducting film, but rather it serves as a barrier to moisture, and improves the overall optical collection efficiency of the bolometer device. At a bias of ImA, and chopping frequency of 100Hz, we have measured photoresponse as a function of device temperature, calculated responsivity, and estimated noise equivalent power (NEP) for each of the three device structures. Peak photoresponse, responsivity, and estimated NEP for the undoped bolometer device are 12μV, 0.6mV(W/cm2), and 2.03×103 W/cmHz1/2 respectively. Peak photoresponse, responsivity, and estimated NEP for the Ag-doped bolometer device are 50μV, 2.5mV(W/cm2), and 9.40×10−8 W/cmHz1/2 respectively. Peak photoresponse, responsivity, and estimated NEP for the stacked structure bolometer device are 70μV, 3.5mV(W/cm2), and 1.02× 10−7 W/cmHz1/2 respectively. These results are the first for Ag-doped YBCO bolometers, as well as for superconducting bolometers fabricated using our novel photoresist/anti-reflective coating method.

Recently, doped rare-earth manganates exhibiting colossal magnetoresistivity have been proposed to be used as the semiconductor channel material for a Ferrolectric Field Effect Transistor. Although the feasibility of epitaxial magnetoresistive/ferroelectric heterostructures have been demonstrated, the leakage in the ferrolectric layer and the strain induced degradation of the magnetoresitive layer remain a principal problem. We present results on fabrication and characterization of epitaxial giant magnetoresistive/ferrolectric La0.7Ca0.3MnO3(LCMO)/PbZr0.52TiO.48O3(PZT) heterostructures. The films have been prepared in situ by a KrF pulsed laser deposition technique on single crystal LaAlO3 substrates from stoichiometric LCMO and PZT targets. The main processing parameters have been optimized to preserve the existence of giant magnetoresitivity in the LCMO films after deposition of the top ferrolectric layer. A high degree of c-axis orientation and a strong in-plane texture coherent with the substrate both in template LCMO and PZT layers, high dielectric permittivity of 1800, remanent polarization of 0.2 C/m2 and a magnetoresistivity of 28% at H=0.5 T indicate excellent characteristics of coexisting magnetoresistive and ferroelectric properties.

Highly (100) textured pseudo-cubic Pb(ScTa)1−xTixO3 (x=0-0.3) (PSTT) thin films were grown by metal-organic chemical vapor deposition (MOCVD) on LaNiO3 (LNO) electrode buffered Si substrates at 650 °C. The microstructure and chemical uniformity were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS). The temperature dependence of dielectric properties and P-E behavior were measured. A shift of Curie temperature of these PST-based thin films due to Ti addition was demonstrated, Furthermore, the pyroelectric properties of these thin films were estimated.