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Properties and Applications of Dielectric Materials, 1997., Proceedings of the 5th International Conference on

Date 25-30 May 1997

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  • Proceedings of The 5th International Conference on Properties and Applications of Dielectric Materials

    Publication Year: 1997 , Page(s): 0_3 - xx
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  • Author index

    Publication Year: 1997 , Page(s): 0_9 - 0_15
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  • Electrical stressed effects of metal-organic chemical vapor deposited high permittivity TiO2 dielectric metal-oxide-semiconductor field effect transistors

    Publication Year: 1997 , Page(s): 1039 - 1042 vol.2
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    Suitable replacement materials for ultrathin SiO2 in deeply scaled MOSFETs such as lattice polarizable films, which have much higher permittivities than SiO2, have bandgaps of only 3.0 to 4.0 eV. Due to these small bandgaps, the reliability of these films as a gate insulator is a serious concern. Ramped voltage, time dependent dielectric breakdown, and capacitance-voltage measurements were done on 190 Å layers of TiO2 which were deposited through the metal-organic chemical vapor deposition of titanium tetrakis-isopropoxide. Measurements of the high and low frequency capacitance indicate that virtually no interface states are created during constant current injection stress. The increase in leakage upon electrical stress suggests that uncharged, near-interface states may be created in the TiO2 film near the SiO2 interfacial layer that allow a tunneling current component at low bias View full abstract»

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  • The microstructure and conduction mechanism of the nonlinear ZnO varistor with Al2O3 additions

    Publication Year: 1997 , Page(s): 867 - 870 vol.2
    Cited by:  Papers (1)
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    The microstructure and electrical properties of nonlinear ZnO varistors with Al2O3 additions are investigated. The variation of nonlinear behavior with Al2O3 additions is indicated from J-E and C-V measurement to be a result of the change of the interface defects density Nt at the grain boundaries and the donor concentration Nd in the ZnO grains. The optimum composition which has a nonlinear coefficient α of ~57 was observed in the sample with 0.005 wt.% Al2O3 additions. The conduction mechanism in the pre-breakdown region is consistent with a Schottky thermal emission process obeying a relation given by J∝exp[-(φ-βE1/2)/kT] and the conduction process at the breakdown region follows Fowler-Nordheim tunneling View full abstract»

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  • Thermally stimulated currents (TSCs) of Langmuir-Blodgett films

    Publication Year: 1997 , Page(s): 650 - 653 vol.2
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    This paper describes the thermally stimulated currents (TSCs) of acidic (AA) and polyamic acid alkylamine salts (PAAS) Langmuir-Blodgett (LB) films. The measurements were performed from room temperature to about 250°C and the temperature was increased at a rate of 0.02°C/s linearly. Peaks of TSCs are observed at about 80°C in the arachidic acid LB films and at about 80°C and 16°C in the PAAS LB films. They indicate that the peak at 80°C is resulted from alkyl group, and the other peak at 160°C is due to alkyl and C-O group in PAAS molecules. The additional large peak at about 160°C is due to dipole moments of the PAAS molecules. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the PAAS and arachidic acid molecules were measured and analyzed View full abstract»

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  • NO2 gas detection characteristics of CuTBP (copper-tetra-tert-butylphthalocyanine) chemiresistor device made by LB technique

    Publication Year: 1997 , Page(s): 1043 - 1046 vol.2
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    We investigated air/200 ppm NO2 gas detection characteristics of CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices. The CuTBP films were made by Langmuir Blodgett (LB) techniques. Sensitivity, response time, recovery time, and reproducibility of the devices were measured by current-voltage characteristics. To increase sensitivity, interdigital electrode was used. It was found that a conductance G increases monotonically as the number of interdigital electrode N increases. And the sensitivity and reproducibility are stable. As far as the current is concerned, the current when N=25 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrode affects the current, sensitivity and stability. We have also investigated applicability of the CuTBP chemiresistor device as a gas detector View full abstract»

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  • The dielectric properties of functional PVDF thin films by physical vapor deposition method

    Publication Year: 1997 , Page(s): 1144 - 1146 vol.2
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    PVDF thin films were fabricated by physical vapor deposition (PVD). The effect of incremental increases of applied electric field on the dielectric constant is related to the one directional array molecular structure. The dielectric absorption moves to higher frequencies with increasing specimen temperature, in accordance with Debye theory View full abstract»

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  • Piezoelectric characteristics of PZ-PT-PMS ceramics with addition of CeO2

    Publication Year: 1997 , Page(s): 875 - 878 vol.2
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    Piezoelectric lead zirconate (PZ)-lead titanate (PT)-lead manganese antimony (PMS) ceramics with various rates of CeO2 addition from 0 to 2 wt.% were prepared. The range of their sintering temperature was from 1100 to 1250°C. The electromechanical properties of PZ-PT-PMS ceramics such as piezoelectric constant, electromechanical coupling coefficient, and mechanical quality factor are estimated as a function of the sintering temperature. The best results of mechanical quality factor and electromechanical coupling coefficient with 0.5 wt.% CeO2 at the sintering temperature of 1200°C were 1989 and 0.545, respectively View full abstract»

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  • Sensor for high-air-humidity measurement using an open capacitor

    Publication Year: 1997 , Page(s): 1047 - 1050 vol.2
    Cited by:  Papers (1)
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    The humidity sensor using the sensitive capacitive-dependent crystal is described Presented is the probe sensitivity (dependence of df on the dCx). In addition, the new idea of excitation of the entire humidity sensor with stochastic test signals is described, and the humidity surface-measuring method is given. It includes the influence of test signals on the weighting function uncertainty and on the A/D-D/A conversion. The results of humidity measurement with the excitation signals are shown experimentally. The uncertainty of the surface humidity measurement is less than 0.2% (T=15-25°C and humidity=50 to 98%) View full abstract»

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  • RuO2 powder preparation and electrical properties in thick film resistors

    Publication Year: 1997 , Page(s): 1147 - 1150 vol.2
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    The powder properties of RuO2 varied with preparation conditions (kind of washing agent, amount of washing agent and calcination temperature). The electrical properties of RuO2 powder thick film resistors (TFRs) were studied. The specific surface area and the resistivity and TCR of TFRs varied greatly with different washing agents. The crystallite size and specific surface area variation with calcination temperature show different characteristics to washing conditions. The resistivity of TFRs decreases and TCR becomes more positive with decreasing crystallite size. TFRs having conductive powder of higher specific surface area at the same crystallite size show lower resistivity and higher TCR values View full abstract»

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  • Dielectric properties of inorganic-organic silica-polyimide composite films prepared via sol-gel and thermal imidization processes

    Publication Year: 1997 , Page(s): 882 - 885 vol.2
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    In this study, we prepared inorganic-organic silica-polyimide hybrid composite films from tetraethoxy silane (TEOS) and polyimide precursors via sol-gel process and thermal imidization. The dielectric properties of the silica-polyimide composite films were investigated. In particular, the dependence of the dielectric constant on the polyimide precursor types was discussed View full abstract»

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  • Evaluation of polymer insulator performance in salt fog chamber

    Publication Year: 1997 , Page(s): 786 - 789 vol.2
    Cited by:  Papers (4)
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    Polymer insulators made of different weathershed materials have been tested in a salt fog chamber at two different salinity (i.e., conductivity) levels for a 500 hour-long test period. The leakage currents flowing through the contamination layer on the surface of the insulators under test, the cumulative charge, and the magnitude and number of leakage current pulses have been monitored. This paper presents the results of salt fog tests performed on silicone rubber and EPDM insulators. In addition, a case study is reviewed. It shows the analysis of the cumulative charge daily profiles for some of the polymer insulators tested View full abstract»

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  • The high resistivity properties of tungsten nitride thin films deposited by RF&DC sputtering

    Publication Year: 1997 , Page(s): 674 - 676 vol.2
    Cited by:  Patents (3)
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    We investigated the high resistivity properties of tungsten and tungsten nitride thin films deposited by RF and DC sputtering system. It deposited at various conditions that determine the resistivity and sheet resistivity. The properties of the resistivity and sheet resistivity of these films measured under various conditions. Resistivity and sheet resistance analyzed the flow rate of the argon gas and contents of nitrogen from nitrogen-argon gas mixtures. We found that these resistivities were depend on the temperature of substrate, gas flow rate and RF power. Very high and low resistivity of tungsten films obtained by DC sputtering. As the increase of contents of nitrogen gas obtained from nitrogen-argon gas mixture, tungsten nitride thin films deposited by the reactive DC sputtering and the resistivities of these films increased View full abstract»

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  • Lithographic properties of SiNx and Se75Ge 25 thin films as the low-energy ion-beam resist

    Publication Year: 1997 , Page(s): 635 - 638 vol.2
    Cited by:  Patents (1)
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    A low-energy focused-ion-beam lithography has been investigated, where low-pressure chemical-vapor-deposited (LPCVD) SiNx and thermal-evaporated(TE) Se75Ge25 thin films are used as resists and exposure is by Ga+-ion sources below 30 keV. Ga+-implanted Se75Ge25 and SiNx thin films act as positive-type and negative-type resists for the development conditions using HNO3+HCl+H2 O wet-etching and CF4 reactive-ion-etching (RIE), respectively. As exposing energy for Se75Ge25 resist increases from 10 to 30 keV, the threshold dose decreases from 4.0×1015 to 1.4×1015 ions/cm2 and then the imaging contrasts appear to be approximately 0.5 and 2.5, respectively. Considering that threshold dose and contrasts in each type resists have a different energy dependence, a predominant factor in this lithography can be understood differently from each other View full abstract»

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  • A study on mechanism of pretilt angle generation in nematic liquid crystal for rubbed polyimide surfaces

    Publication Year: 1997 , Page(s): 946 - 948 vol.2
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    We have studied the effect of the polymer tilt angle for pretilt angle generation in nematic liquid crystal, 4-cyano-4-n-penthylbiphenyl (5CB) on rubbed polyimide (PI) surfaces. The polymer tilt angle was determined by measuring induced optical retardation produced in rubbed PI surfaces by rubbing. We suggest that the polymer tilt angle is not related directly to the pretilt angle on rubbed PI surfaces. We proposed a microscopic model of pretilt angle generation on rubbed PI surfaces. Finally, we conclude that the pretilt angle generation of 5CB strongly depends on the characterization of polymer materials and the micro-asymmetric triangular structure of the polymer on rubbed PI surfaces View full abstract»

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  • Effects of the thickness on the dielectric reliability of multilayered BaTiO3 insulating layer

    Publication Year: 1997 , Page(s): 1026 - 1029 vol.2
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    The dielectric reliability of the multilayered BaTiO3 thin films with different thickness was studied by TZDB and TDDB techniques. The surface roughness and the composition of the thin films were investigated by AFM and AES. The results indicate that TZDB behavior is related to the roughness of the surface of the multilayered BaTiO3 thin films and TDDB characteristics as well as the quantity of the leakage current may be explained in terms of the formation and thickness of the transition region View full abstract»

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  • Electrical characteristics of Al2O3 films using the sol-gel method

    Publication Year: 1997 , Page(s): 879 - 881 vol.2
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    Dielectric films have been prepared by the electrophoretic method from metal alkoxide solutions. The film formation process by hydrolysis of metal alkoxide/alcohol solutions consisted of 3 main stages: preparation of stable organosols with monodisperse particles; electrophoretic deposition; and dehydration of gel, which was formed after electrophoretic deposition on the stainless steel substrates. The authors investigated the influence of sol age on the quality of the films. It was also observed that internal structural variations in organosols significantly alter the sintering behavior of oxide films and affect their subsequent crystalline transformation. The formation properties of Al2O3 thin amorphous films and films armoured by “whiskers” are discussed View full abstract»

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  • Vibration analysis of the stator in ultrasonic motor by FEM

    Publication Year: 1997 , Page(s): 1091 - 1094 vol.2
    Cited by:  Papers (2)
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    A three-dimensional finite element method is proposed for the static and dynamic vibration of the stator in a piezoelectric motor which is comprised of an elastic body with slots bonded with piezoelectric ceramic elements. The validity of the computational technique is confirmed by comparison with experimental results measured by laser vibrometer. It is shown that the amplitude of the effective circumferential direction is dependent on the height of teeth cut out on the surface of the elastic body. If height of teeth is selected appropriately, the piezoelectric motor can be operated without slipping. These facts are useful for designing the shape of stator with high efficiency. The displacement in axial direction remains almost constant View full abstract»

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  • Travelling wave propagation of partial discharges along generator stator windings

    Publication Year: 1997 , Page(s): 1132 - 1135 vol.2
    Cited by:  Papers (5)
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    Generator windings have complicated structures which can significantly attenuate and distort high frequency (above 10-50 MHz) partial discharge (PD) pulses transmitted along the winding. In the lower frequency range under 100-300 kHz, however, the PD pulses suffer only small attenuation and distortion. The dependence of PD pulse transmission on frequency is therefore important for PD measurement on generators. Investigations have been carried out on a number of generators by the authors during the last decade. It has been found from theoretical analysis and test results that within a certain frequency range, a generator stator winding can always be approximately represented by a transmission line. A low voltage impulse test method has been developed to determine the frequency range using spectral analysis and digital filtering techniques. It has also been found that in this frequency range, the travelling wave speed increases with frequency and reaches a constant value which can be used to determine the transit time of the winding. Using the travelling wave of PDs, more accurate apparent charge measurements can been achieved and a new dual CT technique has been developed for the detection and location of partial discharges on generators View full abstract»

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  • Anomalous properties of a metal-insulator composite in a magnetic field

    Publication Year: 1997 , Page(s): 903 - 905 vol.2
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    It is shown a qualitatively new type of the transitions to the nonlinear regime is possible in two-dimensional two-component textures in a magnetic field. The anomalous growth of the effective nonlinearity (the higher moment of the current) are considered near a critical value of the magnetic field. The critical magnetic field value are studied as function of the parameters of the system View full abstract»

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  • Characterization study of plasma polymerized hexamethyldisiloxane thin films

    Publication Year: 1997 , Page(s): 639 - 641 vol.2
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    In this paper, we investigated characteristics of hexamethyldisiloxane thin films by plasma polymerization. Thin films were prepared by interelectrode capacitively coupled type apparatus and in conditions with carrier gas flow rate of 11 [cc/min], gas pressure of 0.1 [Torr], discharge frequency of 13.56 [MHz] and discharge power of 30-90 [W]. The relative dielectric constant and dielectric loss tangent of thin films showed 3.212-3.805 and 0.0026 ~0.0451 in alternating frequency of 103-106 [Hz] View full abstract»

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  • Odd-even effects of the polar anchoring strength for nematic liquid crystal on polyimide Langmuir-Blodgett surfaces with alkyl chain lengths

    Publication Year: 1997 , Page(s): 603 - 605 vol.2
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    The odd-even effect of the alkyl chain length of rubbed polyimide (PI) Langmuir-Blodgett (LB) surfaces on the extrapolation length of 5CB has been successfully evaluated by measuring polar anchoring strength. The extrapolation length of 5CB for rubbed PI-LB surfaces with even numbers is small compared with odd numbers for alkyl chain lengths of greater than 7 carbons. The extrapolation length of 5CB on rubbed PI-LB surfaces with odd numbers increases gradually as the temperature increases but tends to diverge near the clearing temperature (Tc =35.3°C). The extrapolation length diverges because of rapidly decreasing surface order near Tc. It is suggested that the polar anchoring strength on rubbed PI-LB surfaces with an even number is strong because of relatively high surface ordering caused by more crystalline surfaces. Finally, it is concluded that the odd-even effects of the polar anchoring strength in nematic liquid crystals (NLCs) are strongly related to the character of the polymer and observed-clearly for long alkyl chain lengths View full abstract»

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  • Leakage resistance data acquisition system and data for maintenance of transmission line porcelain insulators along coasts in wet snow

    Publication Year: 1997 , Page(s): 794 - 797 vol.2
    Cited by:  Papers (3)
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    The leakage resistance of transmission line insulators along coasts decreases with the accumulation of sea salt due to sea winds; particularly when relative humidity becomes higher and shed surfaces are slightly wet with rain or wet snow. In order to measure the real-time leakage resistance properties of a pilot string of 3 standard suspension porcelain insulator units and a pilot porcelain long-rod insulator which were automatically subjected to 100 V DC voltage, depending on the coast weather conditions, a leakage resistance data acquisition system managed by a personal computer is utilised. Three field test sites were built in December 1995 in an area in Rumoi subject to heavy sea salt contaminated area on the coast of the Sea of Japan. Estimates of insulation deterioration in working insulators for maintenance of transmission line insulators are based on these real-time measurements of pilot insulator leakage resistance and on weather data View full abstract»

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  • Oxygen electrode type multi-biosensor system

    Publication Year: 1997 , Page(s): 1082 - 1086 vol.2
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    A method is presented for the development of the PC-based multi-biosensor system for detecting various components of the aqueous solution by measuring the DO (dissolved oxygen) concentration. The system consists of 6-channel signal conditioning circuits for the multi-cathode type DO sensor probe and PC interface circuits using the single chip microcontroller 80c196kc. Typical polarograms for the DO probes under test using this system are presented. This system covers a wide range of measuring time from 300 seconds to over 16 hours in one measurement step by programming the 9 monitor display modes View full abstract»

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  • Numerical method for computing the resonant frequencies and Q-factor in microwave dielectric resonator

    Publication Year: 1997 , Page(s): 1095 - 1098 vol.2
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    The dielectric resonators (DRs) with dielectric properties are widely used in microwave integrated circuit (MICs) and monolithic microwave integrated circuits (MMICs). The variational method as numerical simulation scheme would be applied to calculate the resonant frequencies(fr) and Q-factors of microwave dielectric resonators. The dielectric resonator with a cylindrical “puck” structure of high dielectric material is modeled in this simulation. The parameters, such as the diameter, the height, and the dielectric constant of dielectric resonator, would determine the resonant frequency and the and Q-factor. The relationship between these parameters would effect each other to evaluate the approximate resonant frequency. This simulation method by the variational formula is very effective to calculate fr and Q-factor in high frequency microwave dielectric resonator. The error rate of the simulation results and the measured results would be considered to design the microwave dielectric resonators View full abstract»

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