Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)
The Korean Institute of Electrical and Electronic Material Engineers
- Annual
1995.11a
-
In this paper, Zinc Oxide films, with a high degree of c-axis orientation, have been grown on glass substrates by a rf magnetron sputtering. The maximum crystal orientation was found to occur with substrate temperature 150
$^{\circ}C$ , input power 190W, oxygen rate 50%, target-substrate distance 55mm. It is proposed to achieve high-resistivity ZnO films by increasing the annealing temperature. The piezoelectric layers, preferred oriented with (002) perpendicular to the layer with 4.9$^{\circ}$ , could be obtained by the annealing temperature 300$^{\circ}C$ in oxygen atmosphere. It is indicated that the relative permittivity is range from 8.9 to 9.8 in the frequency ranging from 10KHz to 5MHz. -
In this study, fur the use of portable communication multilayer devices. 0.15wt% V
$_2$ O$\_$ 5/ added BiNbO$_4$ which is low-fire microwave dielectric ceramic as able to co-fire with high conductors was made into specimens with the additions of Cr$_2$ O$_3$ 0.04, 0.2, 0.4, 0.8, 1.2wt%. These specimens were sintered at 930, 960. 990, 1030$^{\circ}C$ respectively to make the microwave dielectric resonators. These resonators were investigated by measuring the structure and dielectric properties. The density of the specimens was increased by the amounts of the Cr$_2$ O$_3$ and increased by increasing the temperature. 0.8wt% Cr$_2$ O$_3$ added and sintered at 960$^{\circ}C$ specimen skewed 49 dielectric constant. Q$.$ f values were increased by the amounts of Cr$_2$ O$_3$ . And Q value was deteriorated by the additions of Cr$_2$ O$_3$ at sufficiently sintered temperatures. Negative resonant temperature coefficients were moved to positive by the amounts of Cr$_2$ O$_3$ and returned negative again at 1.2wt%. Temperature characteristics were deteriorated at 1030$^{\circ}C$ . -
In this study, crystallization, water swelling and dielectric properties of Li
$_2$ O-MgO-MgF$_2$ -SiO$_2$ System glass ceramics were investigated. Base glass melted at 1450$^{\circ}C$ and crystallized through heat treatment. The optimum heat treatment schedule was 460$^{\circ}C$ for nucleation and 640$^{\circ}C$ , 1100$^{\circ}C$ for crystallization. The Principle crystalline phase was lithium fluorhectorite. Lithium fluorhectorite was the crystal phase which it was influenced water swelling. Samples progressed 2 minutes later they have rapid hydration at forced water swelling condition. Also value of dielectric constants have approximately 10 at 100kHz. -
The electrical conductivity of TiO
$_2$ doped ZnO was investigated by means of complex impedance measurement and voltage-current source and meaurement unit. The e1ectrical conductivity of TiO$_2$ added ZnO was increased with increasing the concentration of TiO$_2$ . The calculated relative dielectric constant was decreased with increasing the concentration of TiO$_2$ . The increase of electrical conductivity seems to be the effect of TiO$_2$ donor doping. -
The (
$Ba_{0.85}Ca_{0.15}$ )$TiO_3$ -Zndielectrics was made by ZnO mol ratio from 0.1 to 0.4. The characteristics of structural was analyzed by SEM and XRD and the insulating properties was examined by dielectric constant and resistivity. The grain size were 1.3[$\mu\textrm{m}$ ] and those shape ware a rectangular. The relativity density were over 90[%] in all specimen. It was found that the best insulating characteristics were obtained for 0.3 mol ratio. -
Particle displacement distributions of the fundamental mode and overtone modes in an energy-frapped single resonator and an energy-trapped double acoustically coupled filter using the thickness shear vibration were calculated. And the effects of the width of a pair of partial electrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back on the displacement distributions of the symmetric vibration mode and anti-symmetric vibration mode of the resonators and the filters were investigated.
-
In this paper, structual, optical and electrical properties of CdZnS thin films prepared by electron beam evaporation method were studied. The crysta1 structure of CdZnS films deposited was hexagonal type with preferential orientation of the (002) plane parallel to the substrate. The results of optical transmittance of the CdZnS film show that absorption edge is shifted to ZnS and optical bandgap was larger wish increasing ZnS content. The resistivity of the CdZnS film is decreasing with increasing ZnS content and mininum for 20 mole%.
-
In this study, dielectric and piezoelectric properties of 0.4[0.1Bi(Ni
$\_$ 1/2/Ti$\_$ 1/2/)O$_3$ 0.9Pb(Ni$\_$ 1/3/Nb$\_$ 2/3/)O$_3$ ]-0.6(PbZr$\_$ y/Ti$\_$ 1-y/)O$_3$ ceramics with Zr/Ti ratio were observed. As a results, structure of the ceramics with ZrO$_2$ (y) 0.425 and 0.45 was MPB. Electromechanical coupling coefficients k$\_$ p/, k$\_$ 31/ of the BN$\_$ 162/ specimen were 57.2%, 35.6% and piezoelectric constants d$\_$ 33/, d$\_$ 31/ were 720, 298[x10$\_$ -12/C/N). -
We have developed the three dimensional mesh generator for three dimensional process simulation using the FEM(Finite Element Method). Tetrahedron element construct the presented three dimensional mesh, which is suitable for the simulation of three dimensional behavior of the LOCOS. The simulation of thermal oxidation is one of the problem in scale downed semiconductor processes. As three dimensional simulators use the huge size of the memory, we use the efficient method that generates the new nodes inside the growing oxide and removes the nodes nearby the SiO2/Si interface in silicon. The resented three dimensional mesh generator was designed to be used in various process simulations, for instance thermal oxidation, silicidation, nitridation, ion implantation, diffusion, and so on.
-
An accurate and efficient single-integral semi-numerical model is developed and applied to analyse effects of localized electronic states in the mobility gap on the drain-current versus gale-voltage characteristics of hydrogenated amorphous field-effect transistors. It is shown that the low-density deep-gap states distributed in the midgap also sensitively and largely influence the device electronic performance as well as well as the large-density tail states distributed near the conduction band edge.
-
Thermally stimulated currents have been measured to investigate the trap characteristics of the MONOS structures with the tunneling oxide layer of 27
${\AA}$ thick nitride layer of 73${\AA}$ thick and blocking oxide layer of 40${\AA}$ thick. By changing the write-in voltage and the write-in temperature, peaks of the I-T characteristic curve due to the nitride bulk traps and the blocking oxide-nitride interface traps ware separated from each other experimentally. The results indicate that the nitride bulk traps are distributed spatially at a single energy level and the blocking oxide-nitride interface traps are distributed energetically at interface. -
The ohmic characterization of Au/Te/Au/n-GaAs structure is investigated by the application of x-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, the specific contact resistance and I-V measurement. Increasing the annealing temperature, the results of XRD measurement show the sharpening of the Au-Ga peak and the increasing of the intensity of Au peak due to the crystallization. At 400
$^{\circ}C$ , which is the ohmic onset point, Ga$_2$ Te$_3$ peak gets evident and GaAs regrowth peak appears for the samples annealed at 500$^{\circ}C$ . The variation of shottky contact to ohmic contact is confirmed by the I-V curve transition. The specific contact resistance of 3.8x10$\^$ -5/$\Omega$ -$\textrm{cm}^2$ is obtained for the sample annealed at 500$^{\circ}C$ and above 600$^{\circ}C$ the specific contact resistance increased due to the decomposition of GaAs substrate. -
Amorpous As
$\sub$ 10/Ge$\sub$ 15/Te$\sub$ 75/ device shows the memory switching characterisite under d.c. bias. In bulk material, a-As$\sub$ 10/Ge/sub15/Te$\sub$ 75/s switching voltage range is above 100 volts. Our purposes in this gaudy are decreasing a switching threshold voltage, finding the properties of d.c., a.c. conduction, and the characterisitics of switching threshold voltage fur a-As$\sub$ 10/Ge$\sub$ 15/Te$\sub$ 75/. As the results, the d.c.and a.c. conductivities increase with temperature. From the data of conductivity, various electrical and physical properties are obtained experimentally. The switching threshold voltages decrease with increasing annealing temperature and time, but increase with increasing film thickness and distance of electrode for d.c. bias. -
In this work, we synthsized GaN powders by the direct reactions of Ga with NH
$_3$ at the temperature range of 950∼1150$^{\circ}C$ and we growth the GaN thin films on Si and sapphire substrates using the synthesized GaN powders by the vapor phase epitaxy method. The synthesized powder had hexagonal crystal structures with lattice constants of a$\sub$ 0/=3.1895${\AA}$ , c$\sub$ 0/=5.18394${\AA}$ . The reaction rates of GaN were increased with both reaction time and temperature, however it did not depends on the flow rates of NH$_3$ . The island type GaN crystals were grown on (0001) sapphire substrates and fast lateral growth of GaN on (111) Si substrate than sapphire was observed in our experiments. -
ZnO varistor with composition of ZnO(90wt%)-Bi
$_2$ O$_3$ (3wt%)-Sb$_2$ O$_3$ (3.6wt%)-CO$_2$ O$_3$ (1.16wt%)-NiO(0.88wt%)-MnO$_2$ (0.71wt%)-Cr$_2$ O$_3$ (0.93wt%) according to Al$_2$ O$_3$ addtive was fabricated by sintering methods. The effects of Al$_2$ O$_3$ dopant on the I-V characteristics of ZnO varistors were investigated. These changes of electric properties were found to be caused by the variation of grains and grain boundary related to Al$_2$ O$_3$ dopting. And the conductive mechanism of ZnO varistor in prebreakdown region were investigated with defect model. -
GaSb crystals were grown by the vertical Bridgman method. P-type GaSb crystals were grown with Ga:Sb=1:1 at % ratio without dopants and with Te, respectively. Also, GaSb:Te crystals were investigated. Lattice constants were 6.117
${\AA}$ for p-type. The carrier concentration, the resistivity, and the carrier mobility measured by the van der Pauw method were p≡8 x$10^{16}$ $cm^{-3}$ , p≡0.20$\Omega$ -cm,${\mu}$ $_{n}$ ≡$400\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ for p-type, n≡1 x$10^{17}$ $cm^{-3}$ , p≡0.15$\Omega$ -cm,${\mu}$ $_{n}$ ≡$500\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ for n-type at 300K. In case of treating with metal ion of$Ru^{+3}$ ,$Pt^{+1}$ , p≡2 x$10^{17}$ $cm^{-3}$ , p≡0.08$\Omega$ -cm,${\mu}$ $_{n}$ ≡420$\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ for p-type, n≡2.5 x$10^{17}$ $cm^{-13}$ , p≡0.07$\Omega$ -cm,${\mu}$ $_{n}$ ≡520$\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ for n-type were obtained. -
A reliable bonding between two silicon wafers, regularly grooved and non-grooved, was done by the direct boning technology, It is Presented that high structural duality was realized not only at the bended interface but in the bulk, commensurate with the filling of artificial grooves, which would be attributed to the dislocation-gettering capability of groove free-surfaces during annealing. The groove filling would be explained with mass-transport phenomena assisted by the dislocation movement from initial contact boundaries toward groove surfaces. Intrinsic voids can be easily removed by aid of the grooves. The proposed method yielded also an intimate bonding not only between {111} wafers strongly misoriented and slightly inclined to {111} basal plane but even between {111} and {100} orientation wafers.
-
In this report the large-signal RF performance of GaN MESFETs at different operating temperatures is investigated using a harmonic balance modeling technique. The predicted device performance calculated by the large-si anal model of a GaN FET is shown to be in good agreement with experimen tar data. It is demonstrated that the optimal RF performance of a GaN MESFET amplifier is achieved by balancing the input impedence for a optimized de sign. A GaN MESFET with the optimized design is predicted to produce maximum RF output power of about 4W/mm and 1W/mm at room temperature and 773 K, respectively. The device produces a peak Power-Added Efficiency (PAE) of 52% and 32% at the two temperatures.
-
Effects of hydrogenation in amorphous silicon rile growths on Solid Phase Crystallization (SPC) was investigated using x-ray diffractometry, energy dispersive Spectroscopy, and Raman spectrum. Interdiffusion of barium(Ba) and aluminum(Al) compounds of corning substrate was observed in both of rf sputtering and LFCVD films under the low temperature(580
$^{\circ}C$ ) annealing. Low degree of crystallinity resulted from the interdiffusion was obtained. Highly applicable degree of crystallinity was obtained through the mechanical damage induced surface activation on amorphous silicon films. X-ray diffraction intensity of (111) orientation was used to characterize the degree of crystallinity of SPC. Nucleation and growth rate in SPC could be controllable through the employed surface treatment. IIydrogenated LPCVD films showed the superior crystallinity to non-hydrogenated sputtering films. Insignificant effects of activation treatment in sputtered film was of activation treatment in sputtered film was observed on SPC. -
GaN films were prepared on Si(111) substrates by hydride vapor phase epitaxy (HVPE) on HCl-NH
$_3$ -N$_2$ gas system. Effects of HCl gas flow rate on the film investigate under deposition conditions of flow time of 10min, 20min, 30min. The deposition rate increased with increasing HCl gas flow rate in the range of 10cc/min to 40cc/min and deposition time. Strung (00.2) oriented GaN film was obtained at a lower HCl flow rate and improved of the surface morphology. -
류완균;최형욱;장낙원;강종윤;백동수;박창엽 1.1
In this study, PLZT thin films in AFE region prepared by sol-gel processing were investigated. And PLZT stock solutions were spin-coated on ITO-glass. The PLZT thin films were annealed by RTA. Hysteresis curves, dielectric characteristics and optical transmittances were measured in order to investigates the characteristics far the thin films. The PLZT thin films were crystallized at 750$^{\circ}C$ for 5 mimutes by RTA and the rosette structure composed of perovskite observed in the thin films. In case La content was 2/90/10 antiferroelectric-ferroelectric phase boundary was 2/90/10 PLZT thin film, and its hysteresis curve was good for application of optical information storage. -
S.Ueyams;S.Nishikawa;K.Akiyama;M.Miyamoto;T.Ogama;S.Isoda 1.2
To investigate the molecular electronic function of artificial flavocytochrome (FC), STM and STS measurement were performed on FC molecules adsorbed on Au (111) surface. At positive bias, many spherical particles with diameter of 3-4 nm were observed. These are considered to correspond to FC. At-900 mV bias at substrate, FC was not observed at all, while the structure of Au substrate was similar to the positive bias images. After changing the bias voltage to positive one, the sane FC images were obtained as before with good reproducibility. This bias dependence of the FC images can be attributed to the rectification function between flavin and heme in FC. In STS measurement, tunneling current increased in positive bras on adsorbed FC area. This rectification result corresponds with the STM images of FC. -
Formation and Characterization of SiOF films using Remote Plasma Enhanced Chemical Vapour DepositionThe inter-metal dielectric SiOF films were fabricated using remote plasma-enhanced chemical vapour deposition with addition of SF
$\sub$ 6/ gas. SiOF bond formation in these films was recognized by a chemical bonding structural study using FT-IR. The deposition rate and the dielectric constant of a deposited films were decreased with increasing SF$\sub$ 6/ gas. It was observed that leakage current of SiOF film was reduced the one order compared to a film without addtion of SF$\sub$ 6/ gas. -
CuInS
$_2$ thin film was prepared by heat treatment at vacuum 10$\^$ -3/ Torr of S/In/Cu stacked layer which was deposited by sequential. And so, the polycrystalline CuInS$_2$ with chalcopyrite structure was well made at heat treatment temperature of 250$^{\circ}C$ and heat treatment time of 60 min. Single phase of CuInS$_2$ was formed from Cu/In composition ratio of 0.84 to 1.3. p conduction type of CuInS$_2$ thin film was appeared from Cu/In competition ratio of 0.99. The highest resistivity of CuInS$_2$ with p type was 1.608${\times}$ 10$^2$ $\Omega$ cm at Cu/In composition ratio of 0.99 and The lowest resistivity was 5.587${\times}$ 10$\^$ -2/$\Omega$ cm at Cu/In composition ratio of 1.3. -
The mechanism of the displacement current generation for stimulation transmit observed in the present displacement current measurement and theoretically analysed. The orientational change of molecules in monolayers was discussed on the basis of the Maxwell-displacement-current obtained. Maxwell displacement current was generated from monolayers on a water surface by monolayerr compression, and it measuring technique has been applied to the study of monolayers of Dipalmitoylphosphatidyl choline (L-
${\alpha}$ -DPPC). Finally, We measured that differential thermal analysis(DTA) of sample. Displacement current was generated when the area per molecule about 180${\AA}$ $^2$ in low pressure, and it was generated when the area per molecule about 110${\AA}$ $^2$ in high pressure. A result of DTA was showed that temperature at 124.6$^{\circ}C$ . -
Fabrication and a new analytical expression for the capacitance characteristics of hydrogenerated amorphous silicon thin film transistors(a-Si:H TFTs) is presented and experimentally verified. The results show that the experimental capacitance characteristics are easily measeured. Measured transfer and DC output characteristic curves of a-Si:H TFT are similar to those of the standard MOSFET-IC. The capacitances on bias voltages are in good agreement with experimental data. This capacitance characteristics is suitable for incorporation into a circuit simulator and can be used for computer-aided design of a-Si thin film transistor integrated circuits.
-
Using metalorganic deposition technique,
$La_2Ti_2O_{7}$ precursor solution was deposited on platinium coated SiO$_2$ /SI(100) substrates by spin-coating process. Crystalline and crack-free films of ∼0.2$\mu\textrm{m}$ thickness were successfully fabricated on the above substrate from four different types of$La_2Ti_2O_{7}$ precursor solutions by proper heat treatment in the temperature range of$700^{\circ}C$ ∼$1200^{\circ}C$ . Microstructure and X-ray diffraction analysis of$La_2Ti_2O_{7}$ thin film showed that the crystallization temperature and the preferred orientation of$La_2Ti_2O_{7}$ thin film were strongly dependent on the precursor used. -
$CdS_{1-x}Te_{1-x}$ polycrystalline thin films were fabricated from CdS and CdTe powder by co-evaporation method at$10^{-6}$ Torr. The Optimum evaporation condition was substrate temperature$T_{s}$ =$150^{\circ}C$ , evaporation time t=30 min. XRD spectrums indicated that the crystal structure chanced from zinc blonde (x$\leq$ 0.22) to wurtzite (x$\geq$ 0.96) through mixed structure (0.22$\leq$0.74) as composition value x increase to CdS. Conductive type was n-type by hot point probe method. van der Pauw method was not applicable for x<0,5 due to high hall voltages, Electrical resistivity and Hall carrier mobility were decreased as x increase, while Hall carrier concentration was increased. The optical bandgap of $CdS_{1-x}Te_{1-x}$ polycrystalline thin films measure d at R.T. had quardratic form and the bowing parameter was fitted as 1.98eV for theoretical value of 2.0eV. I-V characteristics of In/CdTe/$CdS_{x}Te_{1-x}$ Au Schottky diodes showed that CdS-rich one had better forward characteristics than CdTe-rich one. -
This paper presents a method to calculate the escape frequency factor and its verification from TSC(Thermally Stimulated Current) equation and cures. To apply calculation method of ν using asymptotic estimation, it utilized two sets of TSC data with 1K interval. This method enables one to get the exact value of ν and activation energy at the same time by using computer programming. So, it regards their calculation method as a useful process to obtain the value of physical behavior.
-
Polyimide(PI) thin films are fabricated by vapor deposition polymerization(VDP) from PMDA and DDE. The IR spectrum show that PAA the films are changed into PI films by curing. The activation energy of PI films is estimated to be 0.32 [eV] at the electric field of 0.133 [Mv/cm]. The resistivity is about 4.5
${\times}$ 10$\_$ 16/ [$\Omega$ $.$ cm] at room temperature. -
The space charge formation in polyethylene (PE)/ethylene n-butyl acrylate (EnBA) blends were investigated. Heterocharge was found in PE and EnBA containing 5 mole% of nBA while homocharge was found in EnBAs containing 19 and 20% of nBA. All PE/EnBA blends except the one with the EnBA containing 5% nBA showed heterocharge formation. Heterocharge was also found in crosslinked PE/EnBA blends, which was attributed to the volatile residuals generated by the thermal decomposition of peroxide.
-
Excimer laser has been used to fabricate superconducting YBa
$_2$ Cu$_3$ O$\sub$ 7-x/(YBCO) thin films on various substrates. An XeCl excimer laser with an wavelength of 308 nm was used to deposit both buffer layer and superconducting thin film on sapphire substrate. The characterizations of the interface between thin film and substrate were performed. The interfacial properties of thin films on buffered sapphire and on bare sapphire were compared. With a 20 nm PrBa$_2$ Cu$_3$ O$\sub$ 7-x/(PBCO) buffer layer, no diffusion layer was observed between film and substrate while the diffusion layer with about 30 nm thickness was observed between film and sapphire without buffer layer. -
The electron transport coefficients in
$SP_{6}$ gas is calculated and analysed for range of E/N values from 150∼800(Td) by a Monte Carlo simulation, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in neatly agreement with the respective experimental and theoretical for a range of E/N. The validity of the results obtained has been confirmed by a Monte Carlo simulation carried out parallel to the analysis. -
We report rf and power characteristics of AlGaAs/GaAs Heterojunction Bipolar Transistor (HBTs) for X-band power applications. HBTs have been fabricated with polyimide a an interlayer dielectric. By characterizing the DC and RF characteristics we obtained the maximum current gain of 45, BV
$\_$ CEO/ of 10 V, fT of 30 GHz and f$\_$ max/ of 17 GHz for device with 6x14$\mu\textrm{m}$ $^2$ emitter size. To extract accurate equivalent parameters, the De-embedded method was applied for extraction of parasitic parameters and the calculation of circuit equations for intrinsic parameters. Based on the Load-pull method, power characteristics was simulated and measured to get the maximum output power of the device. -
It was investigated the properties of TSC (Thermally Stimulated Current) to understand carriers behavior from long ago. Activation Energy of their properties is very important to verify electrical characteristics. So, for many years, many researchers were worked to get the activation energy, more compeletely. But, if boundary conditions were not satisfied, the values of activation energy contained several errors. In this work, to obtain the activation energy related to charged particles, the peak temperature Tp and the slope of tangential line on any coordinates of Arrhenius plot are applied. The calculation process can be denied with by computer, and the result of observation shows that the cures of calculation data and simulation data coincide very compeletely.
-
LiCoO
$_2$ is a electrode material of Li ion Cell which is expected as the cell with a very high electric charge density. The recent study is mainly to focused on a high power secondary cell. If very thin Li ion Cell can be made in the scale of IC substrate it can be a electric souse in IC chip , micro machine or very thin electrical display etc. LiCoO$_2$ thin film can be made by CVD, Laser ablation, E-Beam, ton Beam process, sputtering etc. But to make the material with a high quality for a cell is difficult as the electrode in cell have the fitable ratio in components and a lattice structure of bulk etc. In this study, LiCoO$_2$ is made by R.F magnetron sputtering with the variance of substrate temperature and oxygen partial pressure etc. In the substrate temperature of 600$^{\circ}C$ and the oxygen rate of 10%, we can acquire the good thin film LiCoO$_2$ compared wish a bulk material. -
Space charge formation in epoxy loaded with silica and calcium carbonate has been studied. The epoxy itself showed almost no charge at up to 40 kV/mm. The addition of fillers such as SiO
$_2$ and CaCO$_3$ resulted in homocharge formation, which was attributed to the interfacial trapping of injected charge at epoxy/filler interfaces. The amount of charge showed a maximum at 20-40 parts per hundred resin above which the charge decreased gradually. This was tentatively attributed to the enhanced interconection of charge transport path by an increased filler content -
Distribution of relaxation time is presented in the Cole-Cole arc diagram with frequency parameter. In the case of estimation of activation energy for main chains, maximum loss frequencies of
${\alpha}$ peaks, f$\sub$ m/(${\alpha}$ ) display curved change according to the WLF type with variations of temperature. Structural change by the filling of filler and degradation by the thermal aging can be estimated from the WLF factors, C$_1$ and C$_2$ in Log f$\sub$ m/-1/T curves which reflect the variations of free volume and thermal expansivity of composites. -
The NO
$_2$ gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett(LB) films of Copper-tetra-tert-butylphthalocyanine(CuTBP). The optimum conditions for a film deposition were obtained through a study of$\pi$ -A isotherms, and the deposited film status was confirmed by the ellipsometry measurements. It was found that at room temperature there are increments of electrical conductivities by 40 times, 25 seconds of response time and 40 seconds of response time when the films were exposed to the 200ppm NO$_2$ gases. We hale observed an increase of the electrical conductivities as the density of NO2 gas increases. -
The fabrication of dielectric multilayer mirror(DMM) optimized at the wavelength of 1.55
$\mu\textrm{m}$ and its spectral properties were investigated. The materials used in the fabrication of DMM are TiO$_2$ -SiO$_2$ , which have the advantage of yielding high reflectance for relatively small numbers of layers. The optical constants of TiO$_2$ single film were obtained by using a modified envelope method. The reflectances of DMMs with 3,7,11 and 23 layers were 58%, 89%, 97% and 99.9% at the wavelength of 1.55$\mu\textrm{m}$ , respectively. -
A Surface Acoustic Wave Gas sensor for NO, CO, H
$_2$ gas detection was designed fabricated, and tested. A delay line device was designed to composite a single mode SAW oscillator which enables to measure a SAW velocity. To reduce the effect of temperature and humidity, dual delay line oscillator circuit was used. And final output was measured by digital frequency counter. NO, CO, H$_2$ gas were detected by WO$_3$ thin film deposited on the path of the Delay Line. -
MCFC has been investigated for the last half centry as an alternative energy source. The operating temperature of MCFC is 650
$^{\circ}C$ , so it is more efficient than ocher fuel cells, and it has needed no nob metal element for the electrodes. we investigated electrochemical characteristics of separator for MCFC. -
In this study, we performed a modeling for
$K^{+}$ ion-exchanged diffused channel waveguide and waveguide-type optical coupler by WKB(Wentzel-Kramer-Brillouim) dispersion equation, field distribution equation of mode and coupled mode theory, and examined the optical-power-dividing of the optical coupler fabricated by using the modeling condition. The optical-power-dividing was observed at the waveguide-type optical coupler with 3[$\mu\textrm{m}$ ] line-width, 6[$\mu\textrm{m}$ ] space between channel waveguides, and 3[mm] interaction length. -
Carbons are the materials which are known to be usable at highest temperature in existing materials and are being increased their mechanical Properties to 2000
$^{\circ}C$ . They have many advantageous characteristics such as electrical and thereat conductivity. But, inspire of their properties, this materials have covalant bonding that strong1y link their atoms. the covalant bondings are too strong to occur atomic diffusions or shirinkages during the sintering. because of this sintering mechanism, carbon materials must be produced by using some binders. To obtain a good carton material, it is important that the function of binders. And to obtain a good binder, it reqired the additive which can improve the properties of the binder, so called curing agent. In this study, we make a curing agent that can improve the properties of binders to evaluate the yield of carbon from binders and to shirink the substrate. and compared the carbon materials treated with the binder containing the curing agent to that treated with common binder. -
An acoustic sensor using PVDF film is proposed in this paper. And its properties, such as sensitivity level, identification of sound source frequencies. and directivity, were experimented. Sensitivity level measured at the distance of 1[m] was limited in the range of
${\pm}$ 10dB. Adjacent three frequencies were also tested to identify the frequency of sound sources. In the range of audible frequencies, it could distinguish the frequencies of a complex sound. In addition, it was found that the sensor outputs were maximum in the coincided direction with a source, when directivity was experimented with three sound sources and FFT. The proposed PVDF film sensor has good characteristics of directivity and identifying ability as an acoustic sensor. -
PZT powders were prepared by the molten salt synthesis method. The porous PZT specimens were prepared from a mixture of PZT and Polyvinylalcohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The pulse-echo response of PZT-polymer 3-3 type composite transducer with various PVA wt.% were studied, The fall time of pulse-echo response of PZT-polymer 3-3 type composite transducer was shorten to that of solid PZT-maded transducer. Therefore, a good transmitting and receiving properties could be obtained. The distance between transducer and reflector was in good agreement both solid PZT and PZT-polymer 3-3 type composite fabricated transducer.
-
In this paper, the
$(Sr_{0.85}{\cdot}Ca_{0.15})TiO_3$ of paraelectric grain boundary layer (GBL) ceramics were fabricated. The characteristics of electrical conduction and the thermally stimulated current(TSC) were measured respectively. The region I below 200[V/cm] shows the ohmic conduction, the region II between 200[V/cm] and 1000[V/cm] can be explained by the Pool-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect. As a result, The origins of these peaks are that the${\alpha}$ peak observed at$-20[^{\circ}C]$ looks like to be ascribed to the ionization excitation from donor level in the grain, and the${\alpha}^{\prime}$ peak observed at$-20[^{\circ}C]$ appears to show up by detrap of the trapped carrier of border between the oxidation layer and the grain, and the${\beta}$ peak observed at$80[^{\circ}C]$ seems to be resulted from hopping conduction of existing carrier in the trap site of the border between the oxidation and second phase. -
Strontium niobate,
$Sr_2Nb_2O_{7}$ was prepared by the molten stilt synthesis (MSS) and the chemical coprecipitation method (CCP). Single phase$Sr_2Nb_2O_{7}$ was obtained by MSS and CCP at$750^{\circ}C$ and$800^{\circ}C$ , respectively. An intermediate phase of composition,$Sr_{5}Nb_4O_{15}$ , appeared at$700^{\circ}C$ when CCP method was employed. The resulting powder was observed to have finer particles and more uniform distribution of particle sizes, as compared to those obtained through the conventional method. Such powder characteristics allowed the use of a much lower sintering temperature of$1400^{\circ}C$ . Grain-orientation along (0k0) direction, which is advantageous for improving dielectric properties, was also observed. The sintering characteristics and the dielectric properties prepared by MSS and CCP, were better than those by the conventional method. -
By substituting Cd
$\^$ 2+/ into both A-site and B-site in PNN-PZ-PT ternary perovskite material, it is possible to determine the effects of the substitution site of Cd$\^$ 2+/ on sintering behavior. Sintering was performed in the temperature range from 1000$^{\circ}C$ to 1300$^{\circ}C$ . The substitution site of Cd$\^$ 2+/ is identified by XPS spectra. Although Cd$\^$ 2+/ is substituted into both A-site and B-site in PNN-PZ-PT, Cd$\^$ 2+/ prefers A-site to B-site. The density is influenced by substitution site of Cd$\^$ 2+/. If Cd$\^$ 2+/ replaces Pv$\^$ 2+/, weight gain is observed during sinterig process. On the contrary, if Cd$\^$ 2+/ replaces Ni$\^$ 2+/, weight loss is promoted during sintering. From these weight changes, it is believed that Cd$\^$ 2+/ changes the bonding strength between B-site cation and oxygen of octahedron in perovskite structure. The changes of lattice parameters as a function of Cd$\^$ 2+/ content were consistent with those of the bonding strength. The densities of A-site-doped compositions were higher than those of B-site-doped composition. -
최우성;박춘배 221
The electrical conductivity of SnO$_2$ added ZnO was investigated using the DC and AC methods. The electrical conductivity of SnO$_2$ added ZnO was decreased with increasing the concentration of SnO$_2$ . The cal쳐lated effective dielectric constants of 3 mol%, 5 mo1%, and 7 mol% are ~7, ~13, and ~120, respectively. The factor of the decrease for the electrical conductivity seems to be the increase of the resistance of grain decreasing the size of grain. -
The micro-patterning by a Bow energy FIB whish has been conventionally utilized far mask-repairing was investigated. Amorphous Se
$\_$ 75/Gee$\_$ 25/ resist irradiated by 9[keV]-defocused Ga$\^$ +/ ion beam(∼10$\^$ 15/[ions/$\textrm{cm}^2$ ]) resulted in increasing the optical absorption, which was also observed also in the film exposed by an optical dose of 4.5${\times}$ 10$\^$ 20/[photons/$\textrm{cm}^2$ ]. The ∼0.3[eV] edge shift for ion-irradiated film was about twice to that obtained for photo-exposed. These large shift could be estimated as due to an increase in disorder from the decrease in the sloop of the Urbach tail. For Ga$\^$ +/ FIB irradiation with a relatively low energy, 30[keV] and above the amount of dose of 1.4${\times}$ 10$\^$ 16/[ions/$\textrm{cm}^2$ ], the irradiated region in a-Se$\_$ 75/Ge$\_$ 25/ resist was perfectly etched in acid solution for 10[sec], which is relatively a short development time. A contrast was about 2.5. In spite of the relatively low incident energy,∼0.225[$\mu\textrm{m}$ ] pattern was clearly obtained by the irradiation of a dose 6.5${\times}$ 10$\^$ 16/[ions/$\textrm{cm}^2$ ] and a scan diameter 0.2[$\mu\textrm{m}$ ], from which excellent results were expected fur incident energies above 50[keV] which was conventionally used in FIBL. -
Phthalocyanine have a good sensitivity to the toxic gases like NO
$_2$ . Also its properties of good chemical and thermal suability give a potential to superiors gas sensing system. Depositioni of Octa(2-ethyhexyloxy) Copper Phthalocyanine is confirmed by transfers ratio, UB/visible spectra and current-voltage (I-V) characteristics. -
To improve the DIBL characteristics of deep sub micron BC PMOSFETs, the methods of DCI(Deep Channel Implantation) and Hale Implantation have been reported. In this study, using the process simulator TSUPREM4, we simulated the 0.25
$\mu\textrm{m}$ and 0.45$\mu\textrm{m}$ gate length BC PMOSFETs applying the both methods to improve the DIBL characteristics, and their electric characteristics were compared to find the mothod suitable far deep sub-half micron BC PMOSFETs, using the device simulator MEDICI. So we found out that the method of Halo Implantation could be applied to deep sub-half micron BC PMOSFETs for 255 Mbit DRAM. -
In short channel MOSFET, it is very important to establish optimal process conditions because of variation of devise characteristics due to the process parameters. In this paper, we used process simulator and device simulator in order to optimize process parameter which changes of the device characteristics caused by process parameter variation. From this simulation, it has been derived to the dependence relations between process parameter and device characteristics. The experimental results of fabricated short channel device according to the optimal process parameters demonstrate good device characteristics.
-
The basic electrochemical and photochemical behavior of ultrathin mono- and hetero-type LB film of amphiphilic Ru bipyridine complex adsorbed on ITO electrode by the Langmuir- Blodgett(LB) method as monolayer and alternating multilayer state. With theoretical equation of cyclic voltammetry for redox species, the cyclic voltammogram were simulated successfully taking account the interaction parameters. We could fit almost all measured voltammograms with k
$^{\circ}$ =72s$\^$ -1/,${\alpha}$ $\sub$ a/=0.44,${\alpha}$ $\sub$ c/=0.54,$\Gamma$ $\sub$ T/=1.4${\times}$ 10$\^$ -10/, k=0.015s$\^$ -1/ values. The AFM images of mono and hetero type LB film surfaces on ITO were also studied. -
Physical, electrical and optical properties of Aluminum(Al) thin films were investigated in order to establish the optimum sputtering parameters in mirror reflection films. Al. thin films deposited on corning glass substrate by DC magnetron sputtering were grown as a variation of the input power, operation pressure and deposition time. The properties of the Al thin films have been discussed by deposition rate, SEM, XRD, sheet resistivity, resistivity and reflectance. Al thin films were obtained at the deposition conditions as follows: operating pressure, 3 mtorr; DC input power desnsitiy, 3W/
$\textrm{cm}^2$ . -
In this paper, the samples are made by the new three-composition seed grain method, in order to obtain the low voltage varistor distributed randomly large seed grain in its bulk. The oscillation phenomena of carriers appeared from current-voltage characteristics under knee voltage is shown by the transient flow of non trapped carriers group in the trap level of intergranular layer, surface state and/or depletion layer. Current oscillation phenomena is hardly shown in the high electric field. The injected carriers from both electrodes are directly flowed from the conduction band of forward biased grain through the intergranular layer into the reverse biased grain, because the trap level in the electric field above the knee voltage is mostly filled.
-
This paper reviewed the methods about cost-processing of diamond stone and thin film. Five different crises of annealing conditions have been discussed with the electrical properties of doping and implantation.
-
The Field Emission Display promises to improve upon the performance of the traditional CRT, while overcoming the CRTs disadvantages in size and weight which limit its use in portable applications. The technical feasibility of the FED has been reviewed and expeceted to move toward the product development.
-
The response speed enhancement in picosecond photoconductor made from RF planar magnetron sputtered hydrogenated amorphous germanium thin film is discussed. Pulsed laser annealing technique was used to fabricate the highly conductive ohmic contacts and to remove the shallow deflects in the deposited photoconductive film using the different laser powers. Measured V-I curve showed -5 times bigger conductance in photoconductive gap than the one used by the conventional vacuum annealing method using strip heater.
-
We have studied the effect of the mesogenic core of nematic liquid crystals (NLCs) for polar (out-of-plane tilt) anchoring strength and surface order parameter on rubbed polyimide (PI) films. The order of polar anchoring strength for NLCs on rubbed PI films is 5CB > PCH5 > CCH5. This order is the same for all rubbing strengths investigated. The surface order parameter for NLCs is 5CB > PCH-5 > CCH5 on rubbed PI films. From these results, we suggest that the polar anchoring strength is strongly related to the surface order parameter.
-
As methane concentration was varietal, the textures of diamond films deposited on Si(100)substrate could be observed by XRD, SEM and Raman spectroscope. As a result, O
$_2$ plasma etching has been useful to observe microscopic structure of diamond films by SEM. The cross section of diamond films deposited on Si(100) substrate with 4% concentration of methane to hydrogen was a polycrystal like a pillar. The diamond crystal like a pillar has been oriented to (110) surface and the high quality diamond with FWHM of Raman spectra being 3.8cm$\^$ -1/ has been grown. As time goes by deposition time, the preferred orientation increases. -
In this paper, the response characteristics of organic gases were investigated by using quartz crystal microbalance(Q.C.M) with different coating materials. The method for pattern was discussed in order to develope gas sensing system using neural network and pattern recognition. we analyzed the response characteristics by the area of frequency shift, which mean affinities of gases for coating material. The results shows that the Parameter made by the area of frequency shift has possibility to be used for pattern recognition and neural network. we found that each gas had different decrease pattern for coating material.
-
We had experiment using LB method that can fabricate molecular order ultra-thin film below 100
${\AA}$ . LB mettled has known as main technology of information society in 21C, because it is nut only free oriention and alignment of molecular but also ability of thickness control as molecular order. In this paper, the fabricated condition and physical properities of functional ultra-thin film of molecular order was investigated and highly efficient ultra-thin film capacitor was fabricated by using ultra-thin LB film for application as electronic device. Possibility of ultra-thin film capacitor was researched by analizing rind measuring electrical properties. Polyimide ultra-thin LB film capacitor was fabricated, ensured theoretically rind experimentally its possibility in range of 10Hz∼ 1MHz through its frequency characteristics. -
A molecular photodiode was fabricated with hetero-Langmuir-Blodgett (LB) film consisting of an electron accepter(A) and sensitizer. N-Allyl-N-[3-propylamido-N\",N\"-야(n-octadecyl)]-4,4-bipyridum Dibromide and 7,8-dimethyl-10-dodecyl isoalloxan-zine were used as A and S units, respectively. By aligning hefter-LB film of A/S units on ITO glass with an aluminium thin film, a molecular photodiode with the structure of Metal/Insulator/Metal(MIM) was constructed. Due to excitation by irradiation with a 460nm monochromatic light source, the photo-induced unidirectional flow of electrons in the MIM device could be achieved and was detected as photocurrents. The direction of energy flow was in accordance with the energy level profile across the LB films. The photo switching function was achieved and the rectifying characteristics was obserbed in the molecular devise.
-
In this Study, it worked to get the degradation characteristics of polymer insulating materials using TSC technique. So, it prepared epoxy composities with sample, the TSC spectroscopy was applied to investigate the influence of interfacial deformation due to inorganic filler and treatments of coupling agents on the network structure and the electrical properties of epoxy composites.
-
In this experiment the specimen is selected for epoxy resin used in the molding compound materials for the power semiconductors. The specimen was divided into the two parts. one is a specimen without irradiation, the other is irradiated with electron beam, of which dose is 1[Mrad], 2[Mrad], 4[Mrad], 8[Mrad] and 24[Mrad], respectively. From the analysis for the physical properties of the specimen, the carbonyl group which is asffact the electrical properties is decreased according to increase the dose of the electron beam. In the measurement of dielectric characteristics among the electrical properties, the frequency dependance of the dielectric characteristics is confirmed that its
${\beta}$ -peak is represented by one peak due to attribute to the main chain below 50[$^{\circ}C$ ], and two peak above the temperature 100[$^{\circ}C$ ]. -
In order to investigate the electrical properties of Transformer Oils, Volume Resistivity for transformer oils was made researches. in this paper, the specimen was produced by irradiation of electron beam, which is divided by the dose, 12[Mrad], 24[Mrad], 36[Mrad]. By investigating the electrical properties of dielectric liquid due to the difference of electron beam irradiation the effect of electron beam irradiation was studied. To measure the physcial properties of transformer Oils, Fourier transfer infrared spectroscopy was investigated. And the study for the electrical properties of dielectric liquid was made by measuring volume resistivity of specimen. the Electrode for the measuring Volume resistivity is formed coaxial cylindrical shape, and its geometric capacitance is confirmed to 16[pF]. In this experiments, Highmegohm meter which is model VMG-1000, was used for the measuring volume resistivity. the applying voltages were DC 100, 250, 500, 1000[V] in the temperature range of 20∼120[
$^{\circ}C$ ]. By means of the result from this experiment the movement of carrier and the physcial constants to contribute dielectric properties is introduced. -
In this study, the properties of Thermally Stimulated Current is measured automatic Data Acquisition System with a A/D Converter set. The A/D Converter set is configured with DIO 8255(Intel), AMD 9513 Timer/Counter and some Programed Controllers. Especially, the numerical method of asymtotic estimation to separate single relaxation curve and physical factors related to charged particles were obtained rapidely and completely. As a result, the data obtained by automatic Acquisition System need to be corrected to average value and the whole control and inspectation system is needed.
-
ITO(indium tin oxide) that is both conductive in electricity and transparent to the visible ray is called transparent conducting thin film. Nowaday, according to the development of flat panel display such as LCD(Liquid Crystal display, EL(electolumine- scence display), PDP(plasma display panel), ECD(electrocromic display), the higher quality in the low temperature process has been asked to reduce the production cost and to have a good uniformity on a large substrate. In this study, we prepared indium tin oxide(ITO) by a cylindrical DC magnetron sputtering with Indium-tin (9:1) alloy target instead of indium-tin oxide target. To reduce the defact in ITO, the effect on ITO by varing the magnetic field intensity and the applied voltage ares studied. the resistivity of the film deposited in oxygen partial pressure of 5% and substrate temperature of 140
$^{\circ}C$ . is 1.6${\times}$ 10$\^$ -1/$\Omega$ $.$ cm with 85% optical transmission in viaible ray. -
This paper describes the dielectric characteristics of
$SF_{6}$ gas in a non-uniform electric field under overvoltages. The breakdown voltage-time characteristics and the breakdown voltage-gas pressure characteristics are measured within a gas pressure range extending from 0.1 to 0.5 [Mpa] for the plane electrode system with a needle-shaped protrusion. The curvature radius of the needle protrusion is 0.5[mm]. Also, the growth process of the predischarge are simultaneously observed. As a result, it is found that the breakdown mechanism and predischarge phenomena are closely associated with the polarity and waveforms of the testing voltage. -
In order to evaluate insulating reliability in epoxy composites, breakdown data were experimented in the temperature range of 20[
$^{\circ}C$ ]∼160[$^{\circ}C$ ]. From these data, various parameters which are used in Weibull distribution could be derived, and using them, the reliability on a breakdown probability was calculated. -
In this study, in case the lead sheath of XLPE cable (radius : 15cm, inner conductor radius : 5cm, insulation paper raidius : 6cm, dc voltage : 1MV) is harmed, so that breakdown process by inhomogeneous eletric field is simulated with Finite Element Method. The result of simulation showed that defect of lead sheath layer caused breakdown.
-
In this Study, The Electrostatic Coutour Distribution in Polymer Electret Acoustic Sensor is calcuated using Finite Element Method. As a result the Electrostatic Countour Distribution is visualized and the design modification could be processed.
-
In this paper, in order to improve withstand voltage properties of epoxy resin, IPN(interpenetrating polymer network) method was introduced and the influence was investigated. The sing1e network structure specimen(E series), simultaneous interpenetrating polymer network specimen(EMF series) and pseudo interpenetrating polymer network(EMP series) specimen were manufactured. In order to understand the internal structure properties, scanning electron microscopy method was utilized, rind glass transition temperature was measured. Also, AC voltage dielectric strength, tensile strength and impact strength were measured to investigate influence upon electrical and mechanical properties. As a result, it was confirmed that simultaneous interpenetrating polymer network specimen was the most execellent.
-
In this research, FEM solution to analysis near field of high Tc superconductor microstrip antenna is presented. This method uses the interpolation function with vector edge triangular element. The advantage of this element is elimination of spurious solutions which are attributed to the lack of enforcement of the divergence condition. The solutions of this method will be used to have a good fundamental data for next reaserch about analysis of HTS microstrip array antenna etc.
-
TiO
$_2$ thin films for humidity sensors have been deposited by RF magnetron sputter and hygroscopic characteristics were investigated. Grain diameter of thin films were increased and hygroscopic characteristics were good as discharge power. Hygroscopic characteristics of thin films heated for 15 min at 500$^{\circ}C$ were better and more linear than that at 400$^{\circ}C$ and were unchanged as Ar flow rate. -
Electrification pipe modeled on the oil path of the high power transformer is designed and manufactured. Distributions of oil flow velocity are simulated as spacer form in the electrification pipe. Streaming currents are investigated as each electrification pipe. The surface oil velocity of spacer is small the streaming current.
-
There has been considerable interest in electrochromic devices because of its potential application in automobiles including mirrors and windows. The electrochromic(EC) mirror can automatically control the amount of glare produced by headlights or other light source on either inside or outside mirrors. Therefore, the EC mirror can be a better alternative to todays day-night mirrors for automobiles. In this paper we have fabricated all solid state EC mirrors with glass-ITO / a-WO
$_3$ / polymer electrolyte / a-V$_2$ O$\sub$ 5/ / ITO-glass / Al structure and investigated their spectral reflectance as a function of applied voltage. -
We prepared
$LiCo_{1-x}Ni_{x}O_2$ by reacting stoichiometric mixture of LiOH.$H_2O$ ,$CoCO_3$ .$xH_2O$ and$Ni(OH)_2$ (mole ratio respectively) and heating at$850^{\circ}C$ for 5n. In the result of X-ray diffraction analysis, along fluctuation of the function of x in$LiCo_{1-x}Ni_{x}O_2$ (003) peak and (104) peak indensities and ratio were varied. We awared through XRD that from 0 to 0.5 at x in$LiCo_{1-x}Ni_{x}O_2$ is well formed for hexagonal structure at one step heat treatment($850^{\circ}C$ ), but if Ni involve at$LiCo_{1-x}Ni_{x}O_2$ hexagonal structure is not well formed. In the result of charge/discharge tests charge/discharge capacity and effiency is different about various cathode. Therefore, the appropriate charge/discharge method must be selected for good characteristics. -
Effect of
$M_{2}CO_{3}$ (M=Li, Na) Addition on the Humidity Sensitivity of$V_{2}O_{5}$ -doped$TiO_2$ In this paper, the effect of alkaline oxides on the humidity sensitivity of$V_2O_{5}$ (2mol%)-doped$TiO_2$ (98mol%) was investigated as functions of$Li_{2}Co_{3}$ ,$Na_{2}Co_{3}$ . III-1. Measurement of Density. When the mole% of$Li_2$ O is varied 0,1,2,5mol%, the more the mole% of additives is increased, the more difference of bulk and apparent density is largely narrowed. The difference of two densities of sample containing 2mol%$Na_2O$ was large all the moat. The sample containing 1mol%$Na_2O$ was small most. III-2. Observation of porosity. The porosity and total intrusion volume according to various amounts of$Li_2O$ was reduced and those of sample containing 2mol%$Na_2O$ as 31.13%, 0.1155mL/g was the highest and 1mol%$Na_2O$ was lowed most and 5, 10mol%$Na_2O$ was more high compare with sample without alkaline oxides. III-3. Characteristic of humidity sensitivity. 1. Impedance of samples containing$Li_2O$ was high compare with sample without alkaline oxides, so we thought it showed Poor sensitivity because it have no impedance changing rapidly as function of relative humidity. 2. When the humidity was increasing from 30RH% to 90RH%, the impedance of sample containing 2mol%$Na_2O$ at 120HZ changed exponential rapidly from 6${\times}$ $10^{7}$ $\Omega$ ) to 1.25${\times}$ $10^4$ $\Omega$ . At under 50RH% and over 50RH%, the humidity sensitivity of samples containing 2mol%$Na_2O$ was best especially in the range of the low humidity. III-4. Characteristic of TG curves. When algal me oxide$M_{2}CO_{3}$ (M=Li, Na) were added into$V_{2}O_{5}$ -doped$TiO_2$ , the stability of humidity sensitivity of samples containing amounts of$Li_2O$ was unstable. The samples containing 1mol%$Na_2O$ was unstable. -
In this paper, we fabricated fuel shortage detecting sensor, utilizing NTC thermistor concerned with Mn-Ni-Co system. We would be obtained B constant value of 1930∼2080 and resistivity 387∼430(ohm-cm) additive Bi
$_2$ O$_3$ 0∼0.5 wt% to Mn$_3$ O$_4$ :9wt%, Co$_3$ O$_4$ :61wt%, NiO:28wt% under 1150∼1250$^{\circ}C$ of sintering temperature. In sensor, we obtained characteristics, which we want, in resistance range 850∼l150$\Omega$ , B constant 2000${\pm}$ 5%. we can see 15 multiplied differences between gasoline and heat dissipation coefficient of air condition. -
A optical switch which on the LiNbO
$_3$ substrate is fabricated by using proton exchange method and self-alignet method. The annealing at 400[$^{\circ}C$ ] was carried out to control waveguide width and depth. A self-aligned method, which doesn\`t need the additional mask precesses, was applied to simplify the fabrication processes and to maximize efficiency of electric field application. The depths of the two annealed optical waveguides, which were measured by using${\alpha}$ -step, ware 1.435[K${\AA}$ ] and 1,380[K${\AA}$ ]. Using${\alpha}$ -step facility, we examined that the width of waveguides is increased from 5[$\mu\textrm{m}$ ] to 6.45[$\mu\textrm{m}$ ] and 6.3[$\mu\textrm{m}$ ] due to the annealing effects. The process of proton exchange was done at 400[$^{\circ}C$ ] for 60[min] and annealing process was done at 400[$^{\circ}C$ ] for 60[min]. The high speed optical modulator has very good figures of merits: the measured voltage of the input waveguide power is 3.5[V], the voltage of the coupling waveguide power is 3.9[mV], and -29.5[dB] crosstalk and 8[V] switching voltage were achieved. -
Since the streaming electrification phenomena of transformer were made clear on 1970s, many researches have been continued on the improvement of the transformer. This paper describes the effect of additive (BTA, DBPC) and temperature on the streaming electrification of the various materials. The streaming current in the various materials decreases in proportion to the concentration of BTA, results in the inverse electrification. We believe that these results will contribute to the optimal design of HV large-capacity transformer.
-
The static charges are generated by streaming electrification phenomena when insulating oil flowing by force for the purpose of cooling at the internal of Ultra-high power transformer. In this thesis, their elimination method was studied. The falter represents a greet much electrification characteristics because falter has large interfaces with liquid. In this paper, the streaming-electrification phenomena of insulating oil by metal filter were measured by mesh number, oil flow rate, oil temperature and a kind of mesh and The effect of charge elimination by metal filter generated minus ion was measured.
-
Charge decay, thermally stimulated current (TSC), charging and discharging currents(I) are measured for corona-charged composite insulating materials. In this study, We will make an experiment in charge decay on composite material surface, TSC, polarity effect and the others in order to analysis its mechanism. Especially, Fiber glass Reinforced Plastics(FRP) is the best composite material which has been so far. Therefore, Its worthy of notice to investigate its characteristic. And then some other materials will be focused on. This experiment measured characteristic of charge decay, dependence of discharging-time and other electrostatic characteristics on FRP.
-
Na, Y.kamura 5.1
Electron swarm studies to derive electron collision cross sections of atoms and molecules from measurements of electron swarm data are reviewed. Stress is placed on those using molecular gas-rare gas mixtures. -
박인길;류기원;배선기;이영희 5.2
0.15($Ba_{1-x}Sr_{x}$ )O-$0.15Sm_2O_3$ -$0.7TiO_2$ (x=0∼9[m/o]ceramics were fabricated by mixed-oxide method. Microwave dielectric properties were investigated with sintering conditions aid Sr addictive. In the specimen with x=0[m/o] sintered at 1350∼1470[$^{\circ}C$ ], dielectric constant, quality factor and temperature coefficient of resonant frequency were 70∼74, 2800∼3300(at 3[GHz]), -1.33∼+l.66[ppm/$^{\circ}C$ , respectively. Increasing the Sr additive from 0 to 5[m/o], dielectric constant and temperature coefficient of resonant frequency were increased and quality factor was decreased. In the specimen with x=r[m/o] sintered at 1375[$^{\circ}C$ ], 6[hr], dielectric constant, quality factor and temperature coefficient resonant frequency were 75.62, 2785(at 3[GHz]), +8.39[ppm/$^{\circ}C$ ], respectively.