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Showing papers on "Dielectric published in 1996"


Journal ArticleDOI
TL;DR: A parametric model was developed to enable the prediction of dielectric data that are in line with those contained in the vast body of literature on the subject.
Abstract: A parametric model was developed to describe the variation of dielectric properties of tissues as a function of frequency. The experimental spectrum from 10 Hz to 100 GHz was modelled with four dispersion regions. The development of the model was based on recently acquired data, complemented by data surveyed from the literature. The purpose is to enable the prediction of dielectric data that are in line with those contained in the vast body of literature on the subject. The analysis was carried out on a Microsoft Excel spreadsheet. Parameters are given for 17 tissue types.

3,985 citations


ReportDOI
01 Jan 1996
TL;DR: In this paper, a database of dielectric data based on measurements using recently developed techniques is presented, and the new data are evaluated by comparison with corresponding data from the literature where available.
Abstract: : Knowledge of the dielectric properties of biological materials is of importance in solving electromagnetic interaction problems. There is, as yet, no consensus on such data among scientists dealing with these issues. This project is geared towards producing a database of dielectric data based on measurements using recently developed techniques. This has been achieved through measurement over a wide frequency range. The new data were evaluated by comparison with corresponding data from the literature where available. To facilitate the incorporation of the dielectric data in numerical solutions, their frequency dependence was modelled to a spectrum characterised by 4 dispersion regions. The conductivity of tissues below 100 Hz was estimated from the recent measurements mitigated by data from the literature and used to estimate the body and of various body parts.

1,995 citations


Book
29 Oct 1996
TL;DR: In this paper, the Gibbs-Duhem relation for binary oxides has been used to derive a Gibbs-Thompson equation for the relationship between Fick's First Law and Eq.
Abstract: INTRODUCTION Introduction Definition of Ceramics Elementary Crystallography Ceramic Microstructures Traditional Versus Advanced Ceramics General Characteristics of Ceramics Applications The Future BONDING IN CERAMICS Introduction Structure of Atoms Ionic versus Covalent Bonding Ionic Bonding Ionically Bonded Solids Covalent Bond Formation Covalently Bonded Solids Band Theory of Solids Summary Appendix 2A: Kinetic Energy of Free Electrons STRUCTURE OF CERAMICS Introduction Ceramic Structures Binary Ionic Compounds Composite Crystal Structures Structure of Covalent Ceramics Structure of Silicates Lattice Parameters and Density Summary Appendix 3A: Ionic Radii EFFECT OF CHEMICAL FORCES ON PHYSICAL PROPERTIES Introduction Melting Points Thermal Expansion Young's Modulus and the Strength of Perfect Solids Surface Energy Summary THERMODYNAMIC AND KINETIC CONSIDERATIONS Introduction Free Energy Chemical Equilibrium and the Mass Action Expression Chemical Stability Domains Electrochemical Potentials Charged Interfaces, Double Layers, and Debye Lengths Gibbs-Duhem Relation for Binary Oxides Kinetic Considerations Summary Appendix 5A: Derivation of Eq. (5.27) DEFECTS IN CERAMICS Introduction Point Defects Linear Defects Planar Defects Summary DIFFUSION AND ELECTRICAL CONDUCTIVITY Introduction Diffusion Electrical Conductivity Ambipolar Diffusion Relationships between Self-, Tracer, Chemical, Ambipolar, and Defect Diffusion Coefficients Summary Appendix 7A: Relationship between Fick's First Law and Eq. (7.30) Appendix 7B: Effective Mass and Density of States Appendix 7C: Derivation of Eq. (7.79) Appendix 7D: Derivation of Eq. (7.92) PHASE EQUILIBRIA Introduction Phase Rule One-Component Systems Binary Systems Ternary Systems Free-Energy Composition and Temperature Diagrams Summary FORMATION, STRUCTURE, AND PROPERTIES OF GLASSES Introduction Glass Formation Glass Structure Glass Properties Glass-Ceramics Summary Appendix 9A: Derivation of Eq. (9.7) SINTERING AND GRAIN GROWTH Introduction Solid-State Sintering Liquid-Phase Sintering Hot Pressing and Hot Isostatic Pressing Summary Appendix 10A: Derivation of the Gibbs-Thompson Equation Appendix 10B: Radii of Curvature Appendix 10C: Derivation of Eq. (10.20) Appendix 10D: Derivation of Eq. (10.22) MECHANICAL PROPERTIES: FAST FRACTURE Introduction Fracture Toughness Strength of Ceramics Toughening Mechanisms Designing with Ceramics Summary CREEP, SUBCRITICAL CRACK GROWTH, AND FATIGUE Introduction Creep Subcritical Crack Growth Fatigue of Ceramics Lifetime Predictions Summary Appendix 12A: Derivation of Eq. (12.24) THERMAL PROPERTIES Introduction Thermal Stresses Thermal Shock Spontaneous Microcracking of Ceramics Thermal Tempering of Glass Thermal Conductivity Summary DIELECTRIC PROPERTIES Introduction Basic Theory Equivalent Circuit Description of Linear Dielectrics Polarization Mechanisms Dielectric Loss Dielectric Breakdown Capacitors and Insulators Summary Appendix 14A: Local Electric Field MAGNETIC AND NONLINEAR DIELECTRIC PROPERTIES Introduction Basic Theory Microscopic Theory Para-, Ferro-, Antiferro-, and Ferrimagnetism Magnetic Domains and the Hysteresis Curve Magnetic Ceramics and their Applications Piezo- and Ferroelectric Ceramics Summary Appendix 15A: Orbital Magnetic Quantum Number OPTICAL PROPERTIES Introduction Basic Principles Absorption and Transmission Scattering and Opacity Fiber Optics and Optical Communication Summary Appendix 16A: Coherence Appendix 16B: Assumptions Made in Deriving Eq. (16.24) INDEX *Each chapter contains Problems and Additional Reading.

728 citations


Journal ArticleDOI
TL;DR: In this paper, the frequency-dependent optical constants, n(ν) and α(ν), for water, methanol, ethanol, 1-propanol, and liquid ammonia were reported.
Abstract: We report the frequency-dependent optical constants, n(ν) and α(ν), or, equivalently, the complex permittivity e(ω) = e‘(ω) − ie‘‘(ω), over the frequency range from 2 to 50 cm-1 for water, methanol, ethanol, 1-propanol, and liquid ammonia. These spectra have been measured with femtosecond terahertz pulse transmission spectroscopy. These liquids exhibit multiple-Debye behavior, making their frequency-dependent dielectric constants valuable benchmarks for molecular dynamics simulations and other theoretical treatments of liquids.

641 citations


Journal ArticleDOI
02 Oct 1996-Langmuir
TL;DR: Using surface plasmon resonance (SPR) spectroscopy in the Kretschmann configuration, this paper followed the self-assembly of organic ultrathin films which resulted from exposure of gold surfaces to solutions of CH3(CH2)n-1SH (n = 8, 12, 16, and 18) in ethanol and heptane.
Abstract: Using surface plasmon resonance (SPR) spectroscopy in the Kretschmann configuration, we followed the self-assembly of organic ultrathin films which resulted from exposure of gold surfaces to solutions of CH3(CH2)n-1SH (n = 8, 12, 16, and 18) in ethanol and heptane We monitored film growth in situ and continuously for up to 72 h with an overall thickness resolution of <1 A Film dielectric constants, necessary for accurately calculating average film thicknesses from SPR spectra, were determined unambiguously for fully formed films by comparing spectra from organic films in different solvents In addition, we introduce a novel two-color SPR experiment with which we can obtain both film thickness and film dielectric constant without changing solvents We studied the chain length dependent and concentration dependent kinetics of film formation in ethanol and found that there are at least three distinct kinetics steps The kinetics of the first, most rapid, step and the third, slowest, step can be described w

443 citations


Patent
04 Dec 1996
TL;DR: In this paper, a wave propagation structure suitable for the transmission of an electromagnetic wave and the formation of resonators within filters is constructed of both high and low dielectric-constant materials.
Abstract: An electromagnetic wave propagation structure, suitable for the transmission of an electromagnetic wave and the formation of resonators within filters, is constructed of both high and low dielectric-constant materials wherein the high dielectric-constant is in excess of approximately 80 and the low dielectric-constant is less than approximately 2. A boundary between the high and the low dielectric-constant materials serves as an electric wall to waves propagating in the low dielectric-constant material and as a magnetic wall to waves propagating in the high dielectric-constant material. This permits substitution of the high dielectric-constant material for metal elements, such as resonators and feed structures in filters. Furthermore, the use of a cladding of dielectric material of one of the foregoing dielectric ranges about a core of material of the other of the foregoing dielectric ranges enables construction of waveguides having rectangular and circular cross-sections. Microstrip and stripline structures with substitution of the high dielectric-constant material for the harmonic elements may also be constructed.

391 citations


Journal ArticleDOI
TL;DR: The dielectric constants of myoglobin, apomyoglobin, the B fragment of staphylococcal protein A, and the immunoglobulin-binding domain of streptococcalprotein G are calculated from 1−2 ns molecular dynamics simulations in water, using the Frohlich−Kirkwood theory of dielectrics.
Abstract: The dielectric constants of myoglobin, apomyoglobin, the B fragment of staphylococcal protein A, and the immunoglobulin-binding domain of streptococcal protein G are calculated from 1−2 ns molecular dynamics simulations in water, using the Frohlich−Kirkwood theory of dielectrics. This dielectric constant is a direct measure of the polarizability of the protein medium and is the appropriate macroscopic quantity to measure its relaxation properties in response to a charged perturbation, such as electron transfer, photoexcitation, or ion binding. In each case the dielectric constant is low (2−3) in the protein interior, then rises to 11−21 for the whole molecule. The large overall dielectric constant is almost entirely due to the charged protein side chains, located at the protein surface, which have significant flexibility. If these are viewed instead as part of the outer solvent medium, then the remainder of the protein has a low dielectric constant of 3−6 (depending on the protein), comparable to that of ...

351 citations


Journal ArticleDOI
TL;DR: In this article, a detailed theoretical study of the dielectric and magnetic response of composites containing elongated conducting inclusions (sticks) is presented, where an approach is proposed that is based on the idea of a scale-dependent local Dielectric constant.
Abstract: We present a detailed theoretical study of the dielectric and magnetic response of composites containing elongated conducting inclusions---sticks. These composites are widely used as engineering materials. They can be also considered as a model to describe many processes occurring in nature, e.g., dielectric enhancement in grain-saturated porous rocks. An approach is proposed that is based on the idea of a scale-dependent local dielectric constant. We develop an effective-medium approximation and derive an equation to calculate an effective dielectric constant of the composites in the quasistatic case and for the high frequency when there is a strong skin effect in the conducting sticks. Our theory predicts very large values of the effective dielectric constant in a wide range of the stick concentration. We find that the dielectric constant can exhibit various dispersive behaviors. It can have relaxation behavior, power-law scaling behavior, or resonance dependence on the frequency. The resonance dependence occurs when the skin effect is strong and wavelength is comparable to the stick length. Then the real part of the dielectric constant has negative values in some frequency ranges. The possibility of a wave localization is discussed in that case. We consider effective magnetic properties of the conducting stick composites. We propose that the composites with nonmagnetic components will have a giant paramagnetic response as a result of a collective interaction of the sticks with an external magnetic field. \textcopyright{} 1996 The American Physical Society.

340 citations


Journal ArticleDOI
TL;DR: The results show that the contacting conductive liquid, in effect, enlarges the electrode area on the liquid side and thereby changes the parallel resonant frequency, and by proper design of the QCM measurement, perturbing effects due to the liquid's electrical properties can be circumvented.
Abstract: Recently, several reports have shown that when one side of a quartz crystal microbalance (QCM) is exposed to a liquid, the parallel (but not the series) resonant frequency is influenced by the conductivity and dielectric constant of the liquid. The effect is still controversial and constitutes a serious complication in many applications of the QCM in liquid environments. One suggestion has been that acoustically induced surface charges couple to charged species in the conducting liquid. To explore this effect, we have measured the parallel and the series mode resonance frequencies, and the corresponding Q factors, for a QCM with one side facing a liquid. These four quantities have all been measured versus liquid conductivity, using a recently developed experimental setup. It allows the simultaneous measurement of the resonant frequency and the Q factor of an oscillating quartz crystal, intermittently disconnected from the driving circuit. Based on these results, a simple model together with an equivalent circuit for a quartz crystal exposed to a liquid is presented. The analysis shows that it is not necessary to infer the existence of surface charges (or other microscopic phenomena such as electrical double layers) to account for the influence of the liquid's electrical properties on the resonant frequency. Our results show that the contacting conductive liquid, in effect, enlarges the electrode area on the liquid side and thereby changes the parallel resonant frequency. By proper design of the QCM measurement, perturbing effects due to the liquid's electrical properties can be circumvented.

317 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of porosity and bulk density on the dielectric constant of soil over a range of moisture contents has been studied, and two equivalent, empirical, normalized conversion functions were found, one accounting for bulk density and the other for porosity.
Abstract: Summary The influence of soiľs solid phase on the dielectric constant of the soil over a range of moisture contents has been studied. Samples of soil, soil-like, and also other porous materials were analysed using Time Domain Reflectometry (TDR) to determine the contribution of bulk density and porosity to the function that relates dielectric constant to water content. The study showed that bulk density, and thus also porosity, substantially affects the relation between dielectric constant and water content. Two equivalent, empirical, normalized conversion functions were found, one accounting for bulk density and the other for porosity. Each of them reduced the root mean square error of the dielectric TDR determinations of moisture to 0.03, regardless of the materialľs bulk density and porosity.

303 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used nanosize crystallites of monoclinic and metastable tetragonal HfO2-Ta2O5 nanolaminates for x-ray diffraction analysis.
Abstract: Dielectric thin films applicable, for instance, as insulating layers in electroluminescent display devices have been studied. In order to improve dielectric characteristics HfO2–Ta2O5 nanolaminates were prepared by atomic layer epitaxy at 325 °C. The nanolaminates were evaluated in capacitance and current–voltage measurements. By optimizing the layer thicknesses in the nanolaminate structures the dielectric properties, especially leakage current densities, could be tailored remarkably. The best nanolaminates showed charge storage factors improved up to 8 times when compared with those of the single oxide films. The presence of nanosize crystallites of monoclinic and metastable tetragonal HfO2 was observed by x‐ray diffraction analysis.

Journal ArticleDOI
TL;DR: In this paper, the ReMnO3 (Re:rare earth) thin films were proposed as a new candidate for nonvolatile memory devices, and the dielectric properties of the epitaxial and polycrystalline YMNO3 films were almost the same.
Abstract: We have proposed ReMnO3 (Re:rare earth) thin films as a new candidate for nonvolatile memory devices. In this letter, we report on fabrication of (0001) YMnO3 films on (111)MgO, (0001)ZnO:Al/(0001) sapphire, and (111)Pt/(111)MgO using rf magnetron sputtering. We succeeded in obtaining (0001) epitaxial YMnO3 films on (111) MgO and (0001)ZnO:Al/(0001) sapphire substrate, and polycrystalline films on (111)Pt/(111)MgO. The dielectric properties of the epitaxial and polycrystalline YMnO3 films are almost the same. The dielectric permittivities of both films are smaller than those reported for YMnO3 single crystal.

Journal ArticleDOI
TL;DR: In this paper, a quantization scheme for the radiation field in dispersive and absorptive linear dielectrics is developed, which applies to both bulk material and multilayer dielectric structures.
Abstract: A quantization scheme for the radiation field in dispersive and absorptive linear dielectrics is developed, which applies to both bulk material and multilayer dielectric structures. Starting from the phenomenological Maxwell equations, where the properties of the dielectric are described by a permittivity consistent with the Kramers-Kronig relations, an expansion of the field operators is performed that is based on the Green function of the classical Maxwell equations and preserves the equal-time canonical field commutation relations. In particular, in frequency intervals with approximately vanishing absorption the concept of quantization through mode expansion for dispersive dielectrics is recognized. The theory further reveals that weak absorption gives rise to space-dependent mode operators that spatially evolve according to quantum Langevin equations in the space domain. To illustrate the applicability of the theory to inhomogeneous structures, the quantization of the radiation field in a dispersive and absorptive one-interface dielectric is performed. \textcopyright{} 1996 The American Physical Society.

Journal ArticleDOI
Ronald Pethig1
TL;DR: In this paper, the basic physical factors influencing the dielectrophoretic behavior of particles are outlined, and ways in which these can be employed to achieve selective separation of cells and microorganisms.
Abstract: Dielectrophoresis is the motion of particles caused by electrical polarization effects in inhomogeneous (nonuniform) electric fields. Unlike electrophoresis, the particles do not require a net electrical charge for motion to occur and AC rather than DC fields are employed to exploit the dielectric properties of the particles. Factors controlling the effective dielectric properties of cells and microorganisms include electrical double layers associated with surface charges, the conductivity and permittivity of their membranes and any cell walls, and their morphologies and structural architectures. In recent years, several laboratories have developed separation and manipulation techniques for cells and microorganisms based on dielectrophoresis, using both static and traveling AC fields. In this article, the basic physical factors influencing the dielectrophoretic behavior of particles are outlined, and ways in which these can be employed to achieve selective separation of cells and microorganisms ar...

Journal ArticleDOI
TL;DR: In this paper, the authors present computer simulation data for the effective permittivity (in the quasistatic limit) of a system composed of discrete inhomogeneities, embedded in a three-dimensional homogeneous matrix of permittivities.
Abstract: We present computer simulation data for the effective permittivity (in the quasistatic limit) of a system composed of discrete inhomogeneities of permittivity e1, embedded in a three‐dimensional homogeneous matrix of permittivity e2. The primary purpose of this paper is to study the related issue of the effect of the geometric shape of the components on the dielectric properties of the medium. The secondary purpose is to analyse how the spatial arrangement in these two‐phase materials affects the effective permittivity. The structures considered are periodic lattices of inhomogeneities. The numerical method proceeds by an algorithm based upon the resolution of boundary integral equations. Finally, we compare the prediction of our numerical simulation with the effective medium approach and with results of previous analytical works and numerical experiments.

Journal ArticleDOI
TL;DR: The dielectric properties of polycrystalline bismuth-based pyrochlores of the general chemical form Bi2(B232+B435+)O7 and B3+B5+) O7 were investigated as a function of temperature and frequency as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the authors studied the dielectric loss of sintered aluminium oxide in an attempt to determine the causes of extrinsic loss, and found that impurities played an important role, but the microstructure also was a key factor.
Abstract: Low dielectric loss materials are required for applications in radio‐frequency and microwave communications. Aluminium is the second most abundant element in the Earth’s crust and aluminium oxide (alumina) is one of the commonest ceramics. Single crystals of aluminium oxide, i.e., sapphire, possess one of the lowest dielectric losses of any material. Polycrystalline alumina has a higher loss due to extrinsic factors. The dielectric loss of sintered alumina is studied in an attempt to determine the causes of extrinsic loss. Impurities are shown to play an important role, but the microstructure also is a key factor. High‐purity aluminas, sintered to near theoretical density, are found to display very low loss, tan δ=2.7×10−5 at 10 GHz. Doping alumina with titanium dioxide was found to reduce the tan δ=2×10−5.


Journal ArticleDOI
TL;DR: In this paper, the effect of postdeposition anneal on the structure and dielectric properties of epitaxial BaxSr1−xTiO3 (BST) thin films (x=0.35) have been measured.
Abstract: The effect of a postdeposition anneal on the structure and dielectric properties of epitaxial BaxSr1−xTiO3 (BST) thin films (x=0.35–0.65) have been measured. The films were grown by pulsed laser deposition on LaAlO3 (001) substrates. The films were single phase and (001) oriented with a lattice parameter larger than the bulk. The dielectric properties of the x=0.35 film exhibited a broad temperature dependence and a peak at 168 K, which is 36 K below the peak observed in bulk BST (x=0.35). Annealing films for 8 h in flowing oxygen at 900 °C caused the lattice parameter to decrease and dielectric properties to become more like the bulk. Annealing also resulted in an increased electric field dependent dielectric tuning without increased dielectric loss.

Patent
Chien Chiang1, David B. Fraser1
10 Sep 1996
TL;DR: In this paper, the authors describe a method for forming interconnections for semiconductor fabrication and semiconductor devices have such connections are described, where a first patterned dielectric layer is formed over a semiconductor substrate and has a first opening filed with conductive material.
Abstract: A method for forming interconnections for semiconductor fabrication and semiconductor devices have such interconnections are described. A first patterned dielectric layer is formed over a semiconductor substrate and has a first opening filed with conductive material. Another patterned dielectric layer is formed over the first dielectric layer and has a second opening over at least a portion of the conductive material. The first patterned dielectric layer may serve as an etch-stop in patterning the other patterned dielectric layer. Also, a dielectric etch-stop layer may be formed over the first patterned dielectric layer and over the conductive material before the other patterned dielectric layer has been formed. This dielectric etch-stop layer may serve as an etch-stop in patterning the other patterned dielectric layer. The second opening exposes a portion of the dielectric etch-stop layer. The exposed portion of the dielectric etch-stop layer is removed. The second opening is filled with conductive material.

Patent
Ajay Jain1, Kevin D. Lucas1
15 Apr 1996
TL;DR: In this paper, an anti-reflective Ta3 N5 coating was used as an etch stop and barrier layer in a dual damascene structure and for I line or G line lithography.
Abstract: The present invention provides an anti-reflective Ta3 N5 coating which can be used in a dual damascene structure and for I line or G line lithographies. In addition, the Ta3 N5 coating may also be used as an etch stop and a barrier layer. A dual damascene structure is formed by depositing a first dielectric layer (16). A dielectric tantalum nitride layer (18) is deposited on top of the first dielectric layer. A second dielectric layer (20) is deposited on the tantalum nitride layer. A dual damascene opening (34) is etched into the dielectric layers by patterning a first opening portion (26) and a second opening portion (32) using photolithography operations. Dielectric tantalum nitride layer (18) serves as an ARC layer during these operations to reduce the amount of reflectance from conductive region (14) to reduce distortion of the photoresist pattern. The use of a dielectric tantalum nitride layer as an ARC is particularly suitable for I line and G line lithography.

Journal ArticleDOI
TL;DR: By analysis of the electric chamber circuit properties, it was able to show that these effects are not due to cell polarization but are instead caused by a dramatic increase in the chamber field strength around 180 MHz.

Patent
Stuardo Robles1
07 Nov 1996
TL;DR: In this paper, a method and apparatus for forming a multilayer insulating film on a substrate involves forming a number of carbon-based layers on the substrate, each interlaid with layers of organic material, such as parylene.
Abstract: A method and apparatus for forming a multilayer insulating film on a substrate involves forming a number of carbon-based layers on the substrate, each interlaid with layers of organic material, such as parylene. Preferably, the carbon-based layers are formed using a high-density plasma chemical vapor deposition system, although other CVD systems may also be used. The result is a multilayer insulating film having a low overall dielectric constant, excellent gap-fill characteristics, and desirable thermal properties.

Journal ArticleDOI
TL;DR: In this paper, the dielectric and structural properties were interpreted in terms of relaxor→ferroelectric spontaneous phase transition, and an intermediate behavior between a relaxor and a real ferroelectric was evidenced.
Abstract: Solid solutions (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 with 0.20≤x≤0.40 were studied using impedance measurements and high resolution x‐ray powder diffraction. The dependence of the real and imaginary parts of the dielectric constant with temperature was investigated on unpoled and poled ceramics, showing several transition points. The temperature dependence of the unit‐cell parameters showed the onset of two successive spontaneous phase transitions: cubic→tetragonal →rhombohedral. A coexistence of both ferroelectric phases was evidenced in a large temperature and composition range. The dielectric and structural properties were interpreted in terms of relaxor→ferroelectric spontaneous phase transition. An intermediate behavior between a relaxor and a real ferroelectric was evidenced. A partial phase diagram was proposed including both structural and dielectric informations.

Patent
10 Oct 1996
TL;DR: In this article, a method for fabricating a flexible interconnect film includes applying a resistor layer over one or both surfaces of a dielectric film, applying a metallization layer over the resistor layer with the resistor layers including a material facilitating adhesion of the dielectrics film and the metallisation layer, and applying a capacitance layer over a capacitor electrode layer.
Abstract: A method for fabricating a flexible interconnect film includes applying a resistor layer over one or both surfaces of a dielectric film; applying a metallization layer over the resistor layer with the resistor layer including a material facilitating adhesion of the dielectric film and the metallization layer; applying a capacitor dielectric layer over the metallization layer; and applying a capacitor electrode layer over the capacitor dielectric layer. The capacitor electrode layer is patterned to form a first capacitor electrode; the capacitor dielectric layer is patterned; the metallization layer is patterned to form a resistor; and the metallization layer and the resistor layer are patterned to form an inductor and a second capacitor electrode. In one embodiment, the dielectric film includes a polyimide, the resistor layer includes tantalum nitride, and the capacitor dielectric layer includes amorphous hydrogenated carbon or tantalum oxide. If the resistor and metallization layers are applied over both surfaces of the dielectric film, passive components can be fabricated on both surfaces of the dielectric film. The dielectric film can have vias therein with the resistor and metallization layers extending through the vias. A circuit chip can be attached and coupled to the passive components by metallization patterned through vias in an additional dielectric layer.

Journal ArticleDOI
TL;DR: In this article, a theoretical treatment based on the Devonshire theory of ferroelectrics is presented to describe the storage of electrostatic energy in ferroelectric and paraelectric materials at very high field strengths.
Abstract: A theoretical treatment, based on the Devonshire theory of ferroelectrics, is presented to describe the storage of electrostatic energy in ferroelectric and paraelectric materials at very high field strengths. In all cases, optimal energy density is achieved by using compositions with Curie temperatures well below the operating temperature. The theory is applied to barium - strontium titanate ceramics and optimal compositions are deduced for energy storage at given working fields. The theory is supported by experimental data showing energy densities up to 8 J at 100 kV .

Journal ArticleDOI
Yasuo Cho1
TL;DR: In this article, a new scanning technique for imaging the state of spontaneous polarization of a ferroelectric material by measuring the microscopic point-to-point variation of its nonlinear dielectric constants is described.
Abstract: This article describes a new scanning technique for imaging the state of spontaneous polarization of a ferroelectric material by measuring the microscopic point‐to‐point variation of its nonlinear dielectric constants. First, the theory for detecting polarization is described. Second, the technique for measuring the nonlinear dielectric response is described. Finally, using this new microscope, area scans are obtained of the polarization of poled lead zirconate titanate ceramics, a lithium niobate single crystal, and of piezoelectric thin films of the copolymer of vinylidene fluoride and trifluoroethylene.

Journal ArticleDOI
TL;DR: Broadband dielectric spectroscopy is employed to study the dynamicGlass transition of low-molecular-weight glass-forming liquids being confined to nanoporous sol-gel glasses with pore sizes of 2.5, 5.0, and 7.5 nm, and it is shown that a bulklike dynamic glass transition takes place in subvolumes as small as about 1 nm.
Abstract: Broadband dielectric spectroscopy (10 Hz–10 Hz! is employed to study the dynamic glass transition of low-molecular-weight glass-forming liquids being confined to nanoporous sol-gel glasses with pore sizes of 2.5, 5.0, and 7.5 nm. As glass-forming liquids, salol ~one hydroxy group!, pentylene glycol ~two hydroxy groups!, and glycerol ~three hydroxy groups! were chosen. We interpret the dielectric spectra in terms of a two-state model with dynamic exchange between a bulklike phase in the pore volume and an interfacial phase close to the pore wall. This enables one to analyze in detail the interplay between the molecular dynamics in the two subsystems ~bulklike and interfacial!, its dynamic exchange, and hence their growth and decline in dependence on temperature and strength of the molecular interactions. For glycerol it is shown that a bulklike dynamic glass transition takes place in subvolumes as small as about 1 nm. @S1063-651X~96!08711-9#

Journal ArticleDOI
TL;DR: In this paper, a single-layer germanium-antimony-tellurium (Ge-Sb-Te) ternary amorphous thin film as a single layer or sandwiched between various dielectric films, such as silicon dioxide (SiO2), siricon nitride (Si3N4), tantalum oxide (Ta2O5), zinc sulfide (ZnS), and ZnS−20 m...
Abstract: Crystallization processes were studied for germanium–antimony–tellurium (Ge–Sb–Te) ternary amorphous thin film as a single layer or sandwiched between various dielectric films, such as silicon dioxide (SiO2), siricon nitride (Si3N4), tantalum oxide (Ta2O5), zinc sulfide (ZnS), and ZnS–20 mol % SiO2. The processes were analyzed quantitatively, based on transmittance changes in Ge–Sb–Te films heated either exothermally or isothermally. Both Kissinger equation and Johnson–Mehl–Avrami kinetic analysis were adopted to estimate activation energy and the reaction order of the processes. Ge–Sb–Te single‐layer amorphous film crystallized in two stages, nucleation and crystal growth. These two processes can be distinguished by exothermal crystallization patterns. By sandwiching this film into dielectric films, crystallization activation energy increases and the nucleation processes are affected. The Si3N4 and Ta2O5 dielectric films accelerate the nucleation, while the SiO2 films inhibit it, and the ZnS and ZnS–20 m...

Journal ArticleDOI
TL;DR: In this paper, the effects of applied electric fields and solvent polarity on the linear and nonlinear optical properties of three prototypical merocyanine (donor−conjugated pathway−acceptor) chromophores of differing architectural types are analyzed using semi-empirical INDO/1 calculations in the presence of imposed static electric fields, using finite-field selfconsistent field (FFSCF), and in the case of solvent dielectrics, self-consistent reaction field (SCRF), models.
Abstract: The effects of applied electric fields and solvent polarity on the linear and nonlinear optical (NLO) properties of three prototypical merocyanine (donor−conjugated pathway−acceptor) chromophores of differing architectural types are analyzed using semiempirical INDO/1 calculations in the presence of imposed static electric fields, using finite-field self-consistent field (FFSCF), and in the presence of solvent dielectrics, self-consistent reaction field (SCRF), models. The NLO properties are computed using the computationally efficient correction vector approach. Both applied electric fields and solvent are found to affect the extent of charge separation induced in the ground states of these molecules. This charge separation leads to a geometric distortion, measured by the bond-length alternation (BLA) parameter, which indexes the geometrical evolution of the molecular architecture from a neutral polyenic structure to a partially ionic cyanine-like structure to an ionic polymethine-like structure. These g...