Matthew Sayer

• Canterbury Christ Church University

A new on-chip Ca5Nb2TiO12 dielectric resonator antenna for 60 GHz radio wireless systems was designed. The proposed rectangular integrated dielectric resonator antenna on conductive silicon (resistivity = 10Ω-cm) 3.2 dB simulated gain with 54% simulated radiation efficiency. With this antennae configuration it was shown that very little Si space wa...

The integration of thin film ferroelectrics with silicon processing is being implemented for various types of devices. The technology is based on the sputtering or chemical deposition of lead-based perovskites such as lead zirconate titanate. Factors concerned with the integration of ferroelectric films with semiconductor processing are described....

The general form of the phase diagrams for impurity-doped VO2 is considered and shown to include mixed phase boundary regions. Phase diagrams for Cr and Al-doped VO2 are established on the basis of the temperature dependence of the 51V nuclear magnetic resonance (NMR) signal. In Cr-doped VO2, the (M2) phase is shown to exist over a smaller temperat...

Measurements of DC and AC conductivity and thermopower show that VO2: W can be treated as a conventional n-type extrinsic semiconductor with a donor level 0.06–0.08 eV below the conduction band. For samples with an impurity content from 0.67 → 1.70 at.% W, an effective mass ratio m*/m of 65 ± 10 and a compensation ratio of 0.7 ± 0.1 are deduced fro...

The temperature dependence of the DC conductivity in the semiconducting phase of undoped and Al, Cr, and Ti-doped VO2 has been interpreted with the aid of AC conductivity and thermopower measurements down to 77 K. A hopping conductivity is shown to be dominant for T < 180 K and to make up about 10% of the total conductivity at the metal–semiconduct...

In many polycrystalline ceramic materials the transport properties are strongly affected by internal barrier effects or by the presence of contact barriers. The transport properties of La1−xSrxCrO3, 0 ≤ x ≤ 0.2 have been investigated and the degree to which these barriers affect the measured transport properties has been established. Measurements o...

Sol gel prepared PZT films from 0.3 - 1.0 μm in thickness can be crystallised at temperatures down to 520°C on aluminium substrates, but such films are often non-ferroelectric. Comparison with films made on Pt substrates suggests that reduced oxygen content at the interface nucleates a cubic non-ferroelectric PZT phase.

The dielectric and piezoelectric response of sol gel based films and composite coatings is affected by the choice of process, gel composition, thermal cycle, processing atmosphere and poling conditions. Important general factors for thin films are the crystallization kinetics and the effects of residual carbon, while a new dielectric technique allo...

A simple process, involving a controlled temperature gradient on the surface of the substrate during the deposition of a thin film is described. This technique is similar to zone-refining but produces chains of impurity free grains. Simultaneously, dopants and other defects are confined to the grain boundaries separating two such chains. For a smal...

Thin films of barium strontium titanate are fabricated on alumina by a hydrothermal method. Crystalline films are produced at temperatures as low as 60°C. The relative dielectric permittivity of films with the composition Ba0.15Sr0.85TiO3 lies in the range between 150 and 220 for low frequencies (100 kHz to 1 MHz), decreasing with frequency. The lo...

Thin PZT films 1-4 μm in thickness prepared by sputtering or sol gel methods allow PZT films to be integrated with silicon technology to achieve piezoelectric or pyroelectric structures having small size or mass. Design criteria, materials and processing techniques for such devices are discussed, and the implementation of small size devices on sili...

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 studie...

Calcium phosphate based thin films prepared by colloidal sol-gel slow draw dipping of quartz substrates are bioactive to both osteoclast resorption and osteoblast deposition. The bioactivity is related to the presence of mixed crystalline phases in the films generated under different sintering conditions. As the sintering temperature was increased...

Lead zirconate titanate (PZT) films of up to 60 μm in thickness have been fabricated on a wide variety of substrates using a new sol gel process. The dielectric properties (∈ = 900), ferroelectric (E c = 16 kV/cm and P r = 35 μC/cm ² ) and piezoelectric properties are comparable to bulk values. The characteristic Curie point of these films is at 42...

Resorbable calcium phosphate (CaP) thin films previously prepared only on quartz substrates were fabricated on Ti-6Al-4V implant grade titanium alloy. In order to maintain the characteristic phase composition and surface morphology of the CaP thin film, an intermediate silica barrier layer was deposited on the titanium alloy via chemical vapour dep...

Small signal dielectric response is reported for a variety of PZT thin film samples. Small and large signal responses, recorded simultaneously during the fatiguing of PZT thin films, are used to identify distinct fatigue mechanisms. Microcracking or electrode delamination less than 100 Å is sufficient to explain the high correlation between the die...

Silicon complexes in silicon doped calcium phosphate bioceramics have been studied using (29)Si magic angle spinning nuclear magnetic resonance spectroscopy with the objective of identifying the charge compensation mechanisms of silicon dopants. Three different materials have been studied: a multiphase material composed pre-dominantly of a silicon...

We report for the first time a 26 GHz K/Ka-band dielectric resonator oscillator (DRO) in 0.8 mum GaAs MESFET that had the Ba₂Ti₉O₂₀ dielectric resonator (DR) grown to the surface of the chip at a temperature of 150degC without destroying the devices of the IC. It was compared to a DRO that had a commercially availab...

This paper presents for the first time the design and performance of a novel integrated dielectric resonator antenna fabricated on a high conducting silicon substrate for system on-chip applications. A differential launcher to excite the TE _01delta mode of the high permittivity cylindrical dielectric resonator was fabricated using the IB...

Recently significant progress in radio frequency on-chip antennas has been demonstrated in view of the advancement in silicon technology. However, the practical uses of these antennas were limited mainly because of the conductor losses in the antenna as well as substrate, surface wave effects and difficulty of integration. To overcome some of these...

The recent advances in millimeter-wave communications have called for parallel development of compact and efficient antennas. This paper addresses the design and performance of a high gain on-chip cylindrical dielectric resonator antenna on conducting silicon. The integrated antenna has a return loss of 46 dB, with an impedance bandwidth of 1720 MH...

A new high gain on-chip dielectric resonator antenna for 60 GHz radio wireless systems is demonstrated. The proposed rectangular integrated dielectric resonator antenna on conductive silicon (resistivity = 10 Omega-cm) has an impedance bandwidth of 1897 MHz at 59.56 GHz and 3.2 dB gain with 54% radiation efficiency, whereas for a similar antenna on...

Silicon doped calcium phosphate materials have drawn great interest as bioceramics for bone repair due to their enhanced bioactivity. However, the low level of doping in these materials, generally ˜1 wt.%, makes it difficult to determine the effects the silicon has on the structure of these materials. In this study, silicon substituted hydroxyapati...

Silicon stabilized tricalcium phosphate (Si-TCP) is formed, among other phases, as a result of sintering hydroxyapatite (HA) in the presence of silica (SiO2) at > 800 degrees C. Calcium phosphate films sintered at 1000 degrees C on quartz substrates are examined with and without additional SiO2 added to the starting precipitate. Data from transmiss...

The electromechanical properties of radio frequency sputtered nichrome (Ni–Cr 80/20 wt.%) films have been evaluated for strain gauge applications. The composition of the films varied slightly from the target composition. Films of various thicknesses ranging from 10 to 400 nm were studied. The 10 nm thick film showed low resistivity, low gauge facto...

Stoichiometric barium strontium titanate (BST) films of composition \({\rm Ba}_{0.7}{\rm Sr}_{0.3}{\rm TiO}_{3}\) with thickness >2 μm have been fabricated on Si/SiO2/Pt substrates by hydrothermal sol-gel composite processing. This film deposition technique involves the treatment of a spun-on sol-gel composite film, formed from a suspension of a po...

Two sets of paramagnetic species having a spectroscopic splitting factor slightly higher than the free electron value are produced in CaWO4 doped with copper after irradiating the crystal with ultra-violet light. One set of lines is identified as being due to a hole trapped at a single tungsten site and is found to bleach out on warming the crystal...

Bioceramics based on silicon stabilized tricalcium phosphate [Si-TCP] have been investigated by attenuated total reflection infrared spectroscopy using an experimental preparation that ensures consistent high-quality spectral data. Phase normalized measurements show that changes in OH bands are primarily due to a decrease in the hydroxyapatite cont...

The sintering of silicon doped calcium phosphate ceramics prepared from a basic colloidal hydroxyapatite (Ca5(PO4)3OH or HA) precipitate mixed with silica over 800 degrees C yields a phase mixture of tricalcium phosphate phases (TCP) designated Si-TCP, beta-TCP and a silicon substituted dehydrated apatite (Si-Ap). The Si-TCP phase is defined as a c...

First Page of the Article

The development of a dielectric grating antenna at K_a band is presented. The antenna performance is analyzed using perturbation analysis and a numerically based commercial software. The effect of the grating profile and various dimensions on the performance is presented. Based on the analytical results a rectangular profile grating anten...

The crystallization kinetics leading to the formation of a characteristic globular, interconnected morphology in the transformation of an unfired hydroxyapatite precipitate (HA) to silicon stabilized tri-calcium phosphate (Si-TCP) are examined by rapid thermal processing of thin films prepared on silica substrates. The results are interpreted using...

The application of thin films in strain gauge technology is well established and nichrome (Ni–Cr 80/20 wt.%) is a commonly used material for application in thin film strain gauges. In the present work, the electromechanical properties of RF sputtered nichrome film have been investigated experimentally for strain gauge applications. The sheet resist...

Silicon stabilized tricalcium phosphate [Si-TCP] is formed within the calcium hydroxyapatite (HA)-tricalcium phosphate (TCP) system when a stoichiometric precipitate of hydroxyapatite is fired at 1,000 degrees in the presence of SiO(2). This paper proposes a composition range and crystallographic structure for Si-TCP. Reitveld XRD powder diffractio...

Thick film broadband ultrasonic transducers (UTs) produced by a sol-gel spray technique and operated below 10 MHz are presented. These UTs are formed by dispersing PZT and LiTaO3 particles, respectively in Al2O3 and PZT sol-gel solution. The 50-100 microm thick films have been deposited on curved steel, flat steel and aluminum substrates and steel...

Zn- and to a lesser extent Mg-releasing tricalcium phosphate (Zn- and Mg-TCP) have excellent bioactivities which do not exist in their parent TCP base. However, the mechanisms through which the dopants affect the properties are not known. In order to gain insight from geometrical and electronic structures and chemical bonding, ab initio density fun...

Results on a new dielectric gratings antenna operating at K/sub a/-band are presented. The antenna is composed of a grounded dielectric slab (/spl epsiv//sub f/=9.8) and dielectric gratings (/spl epsiv//sub g//spl cong/30). The analysis procedure is described. The antenna is fabricated and measured and good agreement between the analytical and meas...

For pt.I see ibid., vol.6, no.24, 3661 (1973). The electrical and optical properties of semiconducting glasses made from 67 MOL% WO3:33 mol% P2O5 and 0.2-8.6 mol% V2O5, MoO3 or CuO have been investigated. V2O5 and MoO3 reduce the conductivity sharply while CuO and most other transition metal oxides have little effect. The dominant parameter is the...

The magnetic effects of small quantities of V2O5, MoO3 and CuO acting as impurities in a 67 mol% WO3:33 mol% P2O5 semiconducting glass have been investigated. The four paramagnetic species that were produced have been attributed to W5+, V4+, Mo5+ and Cu2+ and the magnetic resonance spectrum of each has been characterized at low impurity concentrati...

The high-field electrical properties of several groups of transition-metal phosphate glasses have been examined, especially those based on V, Fe, Cu and Mo ions, and pure and doped tungstates. Conductivity measurements have been carried out under DC and pulse conditions at fields up to approximately 106 V cm-1 but below the fields required for swit...

The electrical properties of La1-xSrxVO3 change from those of a semiconductor to those of a metal as x is increased, with a metal-nonmetal transition occurring at x approximately=0.2. This has been studied using AC and DC conductivity and thermopower measurements over a temperature range from 4 to 400K. Evidence for localization is found in AC cond...

The electrical conductivity of La1-xSrxVO3 (0<or=x<or=0.4) has been measured in the temperature range 170K<or=T<or=1600K. At low temperatures and for small or zero values of x, the material behaves like a conventional impurity semiconductor with conduction resulting from the excitation of carriers from states 0.14 eV above a valence band edge. At h...

Measurements are reported on the AC and DC conductivity of evaporated films and single crystals of MoO3. In both cases a frequency-dependent conductivity is observed at low temperatures, and it is established that this is a true bulk property. A model is developed which shows that long-range potential wells surrounding centres such as (O2-) vacanci...

Synthetic materials capable of being remodelled in vivo by the same processes responsible for natural bone turnover have long been sought for use as an artificial bone substitute. These materials must ideally combine osteoinductive capacity with the ability to withstand random dissolution at normal physiological pH, while being resorbed by natural...

Thick film broadband ultrasonic transducers (UTs) produced using sol-gel spray technique, operating below 10 MHz are presented. These UTs are formed by dispersing PZT and LiTaO₃ particles, respectively in Al₂O₃ and PZT sol-gel solution. The 50-100 μm thick films have been deposited on curved steel, flat steel and al...

The work presented here is a first step toward developing a low cost integrated receiver for LMCS applications. Measurements on the amplifier sub-circuit and circuit analysis on the rest of the receiver suggest that this configuration is feasible for this application. By combining the components, the antenna, the amplifier and the mixer and DRO wit...

Large scale actuated structures often require piezoelectric elements in the thickness range 10-50μm. For manufacturing purposes, the chemical solution deposition of sol gel composites can create such structures using methods compatible with semiconductor fabrication technology. The piezoelectric characteristics of structures fabricated by patternin...

Piezoelectric sol gel composites involve the coating and firing of dispersions of piezoelectric powders within a ferroelectric or piezoelectric sol gel. They provide a means to fabricate piezoelectric coatings of thickness 3–200µm. Such coatings have been used to implement single element and array pulsed ultrasonic transducers at frequencies in the...

A study of the electrical resistivity and microstructure of thin copper films deposited by low-pressure chemical vapor deposition from copper (I) hexafluoroacetylacetonate vinyltrimethylsilane (Cupra Select) was undertaken. Evidence for the nucleation of solid copper in the gas phase at substrate temperatures of about 250 °C is presented. A process...

It has long been the goal of biomaterials research in the field of orthopedics to develop synthetic structures exhibiting comprehensive bioactivity. In particular, an ideal bone-biomaterial would support the activity of osteoblasts in the development of new bone, while simultaneously being resorbed by osteoclasts as part of the lifelong orderly pro...

A stable solution chemistry and a consistent thermal processing route have been developed to produce multi-layer sol-gel lead zirconate titanate (PZT) piezoelectric coatings of high electrical quality. Up to 5 μm thick fully perovskite and piezoelectrically active crack-free coatings with permittivity of 1100–1300 and loss tangents of 1–2% can be p...

Lithium tantalate (LiTaO3)/lead zirconate titanate (PZT) ceramic films of thickness about 50 μm have been deposited on stainless-steel substrates using a modified sol-gel process. LiTaO3 powders are dispersed in a PZT sol-gel matrix to form a 0–3 ceramic/ceramic composite. The dielectric, electric, and piezoelectric properties have been studied. Ul...

A one-transducer self-reciprocal calibration method has been applied to a micromachined capacitance transducer in air over the frequency range 100 kHz~700 kHz. The corrections for air attenuation and transducer diffraction effects at different frequencies are included in this extended reciprocal calibration technique. The measured receive sensitivi...

Techniques to determine the dielectric, mechanical and piezoelectric losses for radial poled spherical, hemispherical, and thickness poled ring resonators were presented. The impedance equations of these resonators were derived from the theory of thin shells as discussed by Berlincourt, Curran and Jaffe. These have been generalized to include loss...

An equivalent circuit model for the unloaded piezoelectric vibrator in the thickness mode is presented. The model contains two branches, the motional branch and the static branch, like the lossless resonator model, but the circuit elements are generalized by making each a complex constant. The mechanical, dielectric and piezoelectric losses associa...

A simple process for improving texture and electrical mobility of polycrystalline films is described. The technique involves annealing the film in a controlled temperature gradient and produces chainlike structures of impurity-free grains; dopants and other defects are confined to grain boundaries. The diffusion of impurities, as well as self-diffu...

A method is developed to determine the elastic and piezoelectric properties of piezoelectric films by the resonance frequency spectrum of a two-layered composite resonator consisting of a film and a substrate plate. The parallel resonance frequencies are determined from the mechanical properties of the two layers only, allowing the density ρˆ and t...

Synthetic bone grafts resistant to random dissolution at physiological pH, yet capable of being gradually resorbed in vitro by osteoclasts have been created. Bulk ceramics and ceramic coatings formed from an additive stabilized colloidal sol possess two characteristic features: a phase mixture of calcium hydroxyapatite (HA) and a silicon stabilized...

A transmission line equivalent circuit network model has been developed to understand and control the high frequency performance of micromachined air-coupled capacitance transducers. The geometric size of the air cavities, the spacing between cavities, diaphragm thickness, air viscosity, bias voltage of the diaphragm and the compressibility of the...

Sol-gel fabricated thick film broadband piezoelectric ultrasonic transducers (UTs) operating at a frequency below 10 MHz are presented. The UTs are formed using thick PZT and LiNbO₃ films which are ceramic-ceramic composites formed by dispersing PZT and LiNbO₃ particles in a PZT and LiNbO₃ sol-gel solution, respecti...

Materials scientists have struggled for a while to find a process which can be used to engineer individual grain boundaries separating two adjacent grains. Considerable effort has also been devoted to finding a technique that can control the orientation of individual grains. A temperature gradient applied during the chemical vapor deposition of thi...

An alternative method to determine the electromechanical coupling constant k13 for the length-thickness piezoelectric resonator is presented. Data relating the electromechanical coupling constant k13 to the parallel resonance frequency ratios are tabulated. A third order polynomial was found to represent the relationship accurately for k13 = 0.01 t...

Lead zirconate titanate (PZT) films 60 μm in thickness have been fabricated using a new sol gel based process. PZT powders are dispersed in a sol gel matrix to form a 0–3 ceramic/ceramic composite. The dielectric properties of these films have been studied as a function of powder concentration, frequency, and temperature. The characteristic Curie p...

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 soluti...

Crystalline bismuth titanate films were fabricated using a modified sol gel method. The process was simplified using stock titanium and bismuth solutions. Films were fabricated using rapid thermal processing with a ramp rate of 100 °C/s to 700 °C for 30 s. The average grain size of films was 175 nm. A dielectric constant in the typical range of 220...

Lead zirconate titanate (PZT) ceramic films of thickness 5-200 μm have been produced on various substrates using a modified sol gel process. A subset of these films (5-27 μm) open the possibility of fabricating ceramic ultrasound transducers in the frequency range of 80-200 MHz. The technique involves mixing PZT powder conventional PZT sol gel to f...

Flexure mode oscillations in steel membranes at frequencies in the kilohertz range can be induced by piezoelectric coatings. The application of such macroscopic structures in the design of film thickness deposition monitors are demonstrated

A set of thickness resonators of PVDF-TrFE copolymer have been characterized as a function of the frequency and DC bias. The first six resonance peaks in the impedance spectra were analyzed to determine the degree of frequency dispersion in the complex elastic, piezoelectric, and dielectric constants. Modeling the dispersion in the material constan...

Lead iron niobate thin films were synthesized using a modified sol gel method. Films processed at temperatures as low as 400 °C had a dielectric constant K≊400. K of ≊1000 and a low loss factor tan δ≊0.02 were obtained for films rapid thermally processed between 650–700 °C. Films processed at ≊400 °C showed a more linear behavior and were able to e...

Chemical methods of preparing ceramic films and coatings have become an important technique for fabricating piezoelectric, ferroelectric and conventional ceramic coatings. This paper reviews sol gel and metallorganic deposition and discusses developments in processing which lead to applications as diverse as electronic devices and protective coatin...

Thick piezoelectric lead zirconate titanate (PZT) films (ceramic–ceramic 0–3 composite films), using a new sol‐gel based process, have been produced and used to coaxially coat optical fibers. Coated PZT of up to 200 μm thick and 10 cm long have been achieved. Using thick PZT coated single mode optical fibers, in‐line phase modulators are designed,...

A computer simulation has been performed of phase transformations taking place in thin films under various time–temperature regimes. The conditions used resemble those encountered in the rapid thermal processing of thin films. The effect of heating rate and final temperature have been studied in detail. It is observed that the two parameters can st...

The pyrochlore to perovskite phase transformation was studied in lead zirconate titanate (PZT) thin films. The films were fabricated on platinum electrodes and annealed by rapid thermal processing (RTP). The phases which formed and their location in the film were analyzed using glancing angle XRD and depth profiling was demonstrated. Grain size and...

The crystallization kinetics of the pyrochlore to perovskite phase transformation in lead zirconate titanate (PZT) thin films have been analyzed using rapid thermal processing (RTP). Sol-gel PZT thin films, fabricated on platinum electrodes, were annealed at 550 °C to 650 °C with hold times ranging from 1 s to 5 min. Glancing angle x-ray diffractio...

Amorphous ruthenium oxide (RuO2) and Ru metal films are fabricated using reactive sputter deposition. The electrodes are then rapid thermally annealed in oxygen to form crystalline RuO2. Control of preferred orientation in the RuO2 using deposition parameters is demonstrated. The sol gel method is used to deposit 200nm PZT films. X-ray diffraction,...

A sol gel based coating technology has been developed for making high quality, thick ceramic coatings. The films are ceramic-ceramic 0–3 composites made by dispersing ceramic powders in a sol gel solution. The resulting system has all the benefits of sol gel, i.e. ease of fabrication, ability to coat complex geometries and relative cost effectivene...

A technique is described for evaluating dielectric data on ferroelectric films using a Cole-Cole distribution function to separate film and electrode capacitance and resistance. The nature of the information obtained, and methods for validating the conclusions are discussed. The method is applied to lead zirconate titanate films on platinum and rut...

The influence of substrate materials on the crystallization kinetics of thin film PZT is presented. Structure and orientation of electrodes affect the nucleation and growth processes of PZT as it transforms from pyrochlore to perovskite. These determine the final film structure and ferroelectric and dielectric properties. Rapid thermal processed so...

The dielectric properties of lead zirconate titanate (PZT) and barium strontium titanate (BST) films were measured in the frequency range of 10mHz-10GHz. Assessment of these films for analog capacitor applications is based on the dielectric dispersion data of the respective material. The capacitor operating frequency range is divided into two regio...

The ferroelectric and dielectric properties of sol gel thin film PZT are affected by the physical structure of the substrate electrodes. Ruthenium oxide electrodes were fabricated using sputter deposition and rapid thermal processing (RTP). Thin film PZT was deposited on these electrodes using sol gel deposition and RTP. The ruthenium oxide was fab...

Experimental and theoretical investigations of optical phase modulation induced by thick piezoelectric lead zirconate titanate (PZT) film coated coaxially on single mode optical fibres are presented for the first time. PZT film thicknesses up to 120 μm have been realised by a sol-gel based process. The measured phase modulation ranges from hundreds...

Integrated gravimetric sensor configurations have been demonstrated by employing a sol–gel processed thin piezoelectric lead zirconate titanate (PZT) film coated coaxially on stainless‐steel tubes and interdigital transducers (IDT) fabricated as the transmitter and receiver on the curved tube surfaces. We have observed tube waves along both the axi...

The fabrication of ferroelectric films of modified lead iron niobate by a multiple magnetron sputtering technique with a subsequent rapid thermal annealing at 800°C for 5 seconds is reported. Since the magnetic properties of pure iron preclude its use in magnetron sputtering, a non-magnetic stainless steel was used as one of the target materials re...

A stock solution sol-gel based method for making Barium Strontium Titanate (BST) thin films has been developed. A modified titanium alkoxide was combined with a barium and/or strontium inorganic salt in methoxyethanol and ethylene glycol to form the solution. The effect of chemistry on the stability of this BST solution is discussed. The crystalliz...

Zirconium hydrogel is an effective dispersing aid and binder for slip casting zirconia. The hydrogel interacts with the ceramic particles in dispersion to form a surface layer on each particle that provides stability for the slip. Removal of the suspending medium causes the hydrogel to undergo further chemical reaction to form an effective binder....

Large area piezoelectric actuators have been fabricated using sol gel PZT films of up to 20 μm in thickness. The dielectric, ferroelectric and piezoelectric properties have been measured and they are consistent with literature values. Simple vibrational structures have been fabricated based on both planar and coaxial substrates. At the resonant fre...

A technique is established for depth profiling of thin film PZT using glancing angle x-ray diffraction. The transformation of PZT from the pyrochlore to perovskite phase is monitored throughout the thickness of the films. Thin film PZT was deposited using the sol gel technique. The effects of substrate, linear ramp rate, hold temperature and hold t...

Titanium isopropoxide, zirconium propoxide and niobium ethoxide have been studied in reaction with 2-methoxyethanol (moe), acetylacetone (acac) and water. Structural information has been obtained using FTIR and 1H, 13C FT NMR spectroscopies. The number of interchanged alkoxy groups increased with increasing excess of 2-methoxyethanol and reaction t...

Four major sol gel or metallorganic decomposition routes for the processing of lead zirconate have been established. The requirements and criteria for successful processing are reviewed, and the concept of a characteristic volume over which the gel is stoichiometric is introduced. The need for solution species of comparable size is outlined and mea...

A thermoelectric generator, or TEG, is a thermodynamic heat engine that passively converts heat into electricity. It is based on the creation of a sodium vapour pressure difference across a Na β'-alumina separator as a result of a temperature difference. The open circuit voltage output is approximately 1 volt for a temperature difference of 700°C....

Ferroelectric films of composition Pb1−xLax(ZryTi1−y)1−x/4)O3(x=0−0.07, y=0.4−0.6) have been prepared on Pt/Ti/SiO2/Si substrates using an alcohol based solgel process reacted at room temperature. FTIR, NMR, DTA, and SAXS measurements have been used to address the chemistry of the alkoxide-alcohol-water-acetylacetone system. Films having 10% lead e...

Ultrasound transducers for B-mode medical imaging are typically operated between 1 and 10 MHz. Research has been directed towards developing transducers that are sensitive in the 10-100 MHz range because a number of clinical problems require higher resolution than can be achieved at the lower frequencies. Using a modified sol-gel technique develope...

Piezoelectric composites prepared by firing ceramic lead zirconate titanate (PZT) powders within a PZT sol gel have a two phase structure in which both phases have high permittivity. Dielectric measurements reflect the presence of the two phases and of interfacial layers between the phases and at the electrodes. The system has been modelled as a) a...

Theoretical and experimental investigations of thin wall tube acoustic wave devices for gravimetric sensing applications are presented. Integrated sensor configurations have been demonstrated by employing a sol-gel processed thin piezoelectric lead zirconate titanate (PZT) film coated coaxially on stainless steel tubes and interdigital transducers...

The dielectric properties and the sources of electrical noise in ferroelectric capacitors (resistive, dielectric, ‘excess’ or 1/f) provide information as to the internal structure of the device and of its processing. This information and the conclusions drawn from it are discussed for ferroelectric capacitors on silicon. The contribution from /f no...

The etching reactions of lead zirconate‐titanate (PZT) films with fluorine ions were studied by in situ x‐ray photoelectron spectroscopic (XPS) analysis of the ion bombarded films. The bombardment was carried out with a mass separated low energy ion beam in ultrahigh vacuum and at 30 and 40 eV. It was found that the bombardment at 30 eV and a dose...

A system consisting of four sputter-etching targets carried by a rotational drive carousel is described. It can be used to deposit successive thin and thick layers of metallic and non-metallic materials on a range of substrates using rf or dc sputtering. The system has the following features: (1) it is simple in construction and easy to operate; an...