Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)
The Korean Institute of Electrical and Electronic Material Engineers
- Annual
1996.05a
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The dependence of microstructural and optical properties of Ag-In-Sb-Te thin films on annealing heat-treatments was studied. It was found from the present work that the increase of reflectance after annealing heat-treatment is related with phase change of Ag-In-Sb-Te thin film from amorphous state to crystalline phases which involve Sb crystalline phase and AgInTe
$_2$ stoichiometric phase. On the other hand, the reflectance is decreased after high temperature annealing (above 450$^{\circ}C$ ), due to the morphology .mange of film surface. For the purpose of practical application(erasable optical disk), we fabricated quadrilayered Ag-In-Sb-Te alloy disk, and annealed it with continuous laser beam. As result of this laser\ulcorner annealing treatment, we found that the increment of reflectance is 9.3% at 780nm wavelength. It might be considered that Ag-In-Sb-Te alloy optical disk is the big promising candidate for the erasable optical memory medium. -
The elemental segregation in the sputter-deposited AgInSbTe recording thin films was studied by means of Auger electron spectroscopy and ESCA for the specimens of as-deposited and as heat-treated conditions. Auger electron spectroscopy and ESCA revealed an extremely thin layer of elemental inhomogeneity, especially for the silver, even in as-deposited condition. The chemical analysis results obtained in this alloy system are discussed in terms of process parameters and target microstructure.
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GaN films were prepared on Al
$_2$ O$_3$ (1120) substrates by hydride vapor phase epitaxy (HVPE) with HCl-NH$_3$ -N$_2$ gas system. The growth rate was increased with increasing the substrate temperature below 1050$^{\circ}C$ and decreased over the temperature, increased with growth time. The X-ray diffraction patterns showed only (0002) GaN peak. The UV-Visible Spectrophotometer showed a good optical absorption and fundamental absorption occurred at 3700${\AA}$ . -
고주파 스퍼터링 방법에 의하여 상온에서 Si(100)기판 위에 AIN막을 형성하였다. 기판의 온도, 고주파 출력, 스퍼터링 시간, 질소의 비율을 변화인자로 해서 각 조건하에서 제작된 AIN의 결정질을 X선 회절법, 적외선 분광법, 전자현미경으로 상호비교 하였다. 자외선 투과법에 의해, 제작된 AIN 막의 금지대 폭은 4.27eV 이었다. 질소 비율에 따른 AIN 막두께의 변화는 질소비율 40∼60%에서 급격하게 일어났다.
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In this paper, we prove through the experiments the possibility that Co-amorphous magnetic films can be used as high sensibility materials. We fabricate amorphous film of Fe
$\sub$ 4.7/Co$\sub$ 74.3/Si$_2$ B$\sub$ 19/ by using sputtering method at high frequency. Then, we not only measure the magnetic Properties of the annealed samples, but also observe the magnetic domain by using an Kerr effect optical-microscope. As the result, we find that the samples have high sensibility -
In this paper, the rheological chances in sensitive materials was investigated by using QCA(Quartz Chemical Analyzer). Langmuir-Blodgett method was used to transfer sensitive material to the quartz crystals because of its facility to control that amount, and deposited sensitive material has uniformity to compare with other methods respectively. For the gas sensor using mass loading effect of quartz crystal microbalance, generally the Sauberary equation has been believed to represent the only mass loading effect. But when the organic gas is adsorpted into sensitive material, the rheological changes are occurred with different pattern as to the kinds of gases. Thus, much simpler method to identify the organic or hazard gas will be obtained by the consideration of resonant frequency changes and resonant admittance changes simultaneously.
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In this Paper, optical absorption were performed on LB films of binary mixtures of three kinds of merocranine dyes DO, DS, and 6Me-BS, where DS and 6Me-DS form J-like aggregates but not DO in single component films. The observed optical absorption spectra of mixed films were markedly defendent on the combination of dyes. [6Me-DS]
$\sub$ 1-x/[DOl]$\sub$ x/ LB films show a sharp red shifted J-like band peak in the whole concentration range. We found the formation of f aggregates in a mixed merocyanine dyes containing a non J-aggregate forming dye DO, in a single component case. Farther investigations on the present and other mixed-dye films will be needed to clarify these points. -
The pressure-area isotherm of monolayer at the air-water interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystal by conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) film on quartz slides and spectrum of monolayer formed on quartz crystal have been measured. The photoisomerization of the long-chain fatty avid containing azobenzene were obtained by the application of UV and visible light. The reversibility of photoisomerization were more clear difference when the number of C
$\_$ n/ increased. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of C$\_$ n/ increased, A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were also obtained by application of UV and visible light. So the LB film of long-chain fatty acid containing azobenzene has possibility to being applies to functional molecular devices such as photomemory and light switching. -
In this paper, xPb(Zn
$\_$ 1/3/Nb$\_$ 2/3/)O$_3$ -yPbTiO$_3$ -zPbZrO$_3$ -zPbZrO$_3$ (0.5wt%)MnO$_2$ ceramics were fabricated by the mixed oxide method sintered at 1250$^{\circ}C$ for 2[hrs] and then the dielectric and pyroelectric properties were investigated. In 0.10PZN-0.45PT-0.47PZ sample, dielectric constant was 829 and in the case of 01.5PZN-0.45PT-0.40PZ sample, pyroelectric current and pyroelectric coefficient were 0.95 x 10$\^$ -7/ [A] and 7.6 x 10$\^$ -1/ [C/$\textrm{cm}^2$ $.$ $^{\circ}C$ ]. Figure of merits of pyroelectric current and voltage and detectivity, in same sample, has shown good properties, that were 2.4 x 10$\^$ -8/[C$.$ cm/J], 5.5 x 10$\^$ -11/[C$.$ cm/J], 1.6 x 10$\^$ -8/ [C$.$ cm/J]. -
This paper reports the studies of the inversion layer mobility in p-channel Si MOSFET's under hot-carrier degradated condition. The validity of relationship of hot carrier degradations between the surface effective mobility and field effect mobility and are examined. The effective mobility(
${\mu}$ $\_$ eff/) is derived from the channel conductances, while the field-effect mobility(${\mu}$ $\_$ FE/) is obtained from the transconductance. The characteristics of mobility curves can be divided into the 3 parts of curves. It was reported that the mobility degradation is due to phonon scattering, coulombic scattering and surface roughness. We are measured the mobility slope in curves with DC-stress [V$\_$ g/=-3.1v]. It was found that the mobility(${\mu}$ $\_$ eff/ and${\mu}$ $\_$ FE/) of p-MOSFET's was increased by increasing stress time and decreasing channel length. Because of the increasing stress time and increasing V$\_$ g/ is changed oxide reliability and increased vertical field. -
A new type CuN/Cu/CuN thin film electrode material with high adhesion to glass was developed by the dc reactive planar magnetron sputtering system for the PDP(Plasma Display Panel). The adhesive force of the CuxN thin film was in the range of 20∼40(N) under the conditions of the N
$_2$ partial pressure of 15%, discharge current of 70mA, discharge voltage of 450v and substrate bias voltage of -100V. The adhesive force was depended on the N$_2$ partial Pressure, discharge current and substrate bias voltage. -
Plasma displays (PDP) as a large area wall-hanging display device are rabidly developed with flat CRT, TPT LCD and etc. Especially, AC Plasma Display Panels(AC PDPs) have the inherent memory function which is effective for large area displays. The memory function in AC PDPs is caused by the accumulation of the electrical charge on the protecting layer formed on the dielectric layer. This MgO protective layer prevents the dielectric layer from sputtering by ion in discharge plasma and also has the additional important roll in lowering the firing voltage due to the large secondary electron emission coefficient). Until now, the MgO Protective layer is mainly formed by E-Beam evaporation. With increasing the panel size, this process is difficult to attain cost reduction, and are not suitable for large quantity of production. To the contrary, the methode of shuttering are easy to apply on mass production and to enlarge the size of the panel and shows the superior adhesion and uniformity of thin film. In this study, we have prepared MgO protective layer on AC PDP Cell by reactive magnetron sputtering and studied the effect of MgO layer on the surface discharge characteristics of ac PDP.
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In this paper, effect of MnO
$_2$ addition(0, 0.1, 0.2, 0.3, 0.5wt%) on the microstructure, dielectric and piezoelectric properties of [xPMW - (0.15-x) PNN] - [yPT-(0.85-y)PZ] (x=0, 0.01, 0.02, 0.03, 0.05, y = 0.35, 0.40, ().425, 0.45, 0.5) were investigated. When Ti/Zr ratio was 1.0, dielectric and piezoelectric properties were highest value. With PMW 2mol%, dielectric constant, dielectric constant (d$\_$ 33/, d$\_$ 31/) and electromechanical coupling factor (kp, k$\_$ 31/) were highest values of 1995, 479, 186(x10$\^$ -12/C/N), 0.61, 0.36, respectively. With the addition of MnO$_2$ , dielectric constant, electromechanical coupling factor (kp, k$\_$ 31/) were decreased, but with 0.3wt% MnO$_2$ , eletromechanical coupling factor was highest value of 0.63. With the addition of MnO$_2$ , mechanical quality(Q$\_$ m/ was increased. -
In the study, the thermal and optical properties of SiO
$_2$ -PbO-K$_2$ O-Al$_2$ O$_3$ g1asses were investigated. According to Ga$_2$ O$_3$ addictions, the properties of bulk glass, transition temperature and softening temperature were increased, whereas thermal expansion coefficient was decreased; In the optical properties, refractive index was increased, and IR cut-off wavelength was enlarged from 4.64$\mu\textrm{m}$ to 5.22$\mu\textrm{m}$ . But, the optical loss of fiber was decreased. -
A hydride vapor phase epitaxy (HVPE) method is performed to prepare the GaN thin films on c-plane sapphire substrate. The full-width at half maximum of double crystal X-ray rocking curves from 20
$\mu\textrm{m}$ -thick GaN was 576 arcsecond. The photoluminescence spectrum measured 10 K shows the hallow bound exciton (I$_2$ ) line and weak donor-acceptor peak, however, there was not observed deep donor-acceptor pair recombination indicate the GaN crystals prepared in this study are of high purity and high crystalline quality. The GaN layer is n-type conducting with electron mobility of 72$\textrm{cm}^2$ /V$.$ sec and with carrier concentration of 6 x 10$\^$ 18/cm/sup-3/. -
Polypyrrole films were electrochemically synthesized under a constant current condition ranging from 50
${\mu}$ A/$\textrm{cm}^2$ to 2 mA/$\textrm{cm}^2$ with resultant high electrical conductivity about 100 S/cm. Specific energy of 70 Wh/kg and Ah efficiency of 97% were achieved during the cycling using liquid electrolyte system. On the other hand, consequences of the cycling were 51 Wh/kg and 95% using PEO$\sub$ 8/LiClO$_4$ PC$\sub$ 5/EC$\sub$ 5/ solid electrolyte system. Polypyrrole film can be cycled stable and Ah efficiency is excellent, so it can be applicable to the cathode of Lithium secondary batteries. -
Among the fuel cell system, solid oxide fuel eels is constructed of ceramics, so stack construction is simple , power density is very high, and there is no corrosion problems. The purpose of this research is investigate the characteristics of unit cell for SOFC .
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The nucleation and growth of microporosities was observed during the course of annealing treatment of sputter-deposited AgInSbTe thin films. There was a close correlation between the density of microporosity and the sputtering gas pressure in annealed thin films. The void density for a given composition decreased with sputtering gas pressure. It was shown from the present study that the number of porosities decreased while the average porosity size increased as the annealing temperature and holding time increased. The mechanism of porosity formation in the sputter-deposited AgInSbTe thin flus containing Ar-impurity trapped from the Ar-plasma is discussed in the present article.
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The conduction mechanisms of the off-current in low temperature (
$\leq$ 600$^{\circ}C$ ) processed polycrystalline silicon thin film transistors (LTP poly-Si TFT's) has been systematically studied. Especially, the temperature and bias dependence of the off-current between unpassivated and passivated poly-Si TFT's was investigated and compared. The off-current of unpassivated poly-Si TFT's is due to a resistive current at low gate and drain voltage, thermal emission current at high gate, low drain voltage, and field enhanced thermal emission current in the depletion region near the drain at high gate and drain voltage. After hydrogenation, it was observed that the off-currents were remarkably reduced by plasma-hydrogenation. It was also observed that the off-currents of the passivated poly-Si TFT's are more critically dependent on temperature rather than electric field. -
The x-ray diffraction experiments were carried out to investigate the phase transformation of the sputter-deposited Ag-In-Sb-Te optical thin films after rapid thermal annealing and while being annealed with high-temperature x-ray attachment. The formation mechanism of the reported mixed phase, with both amorphous phase and fine crystalline AgSbTe2 phase, of Ag-In-Sb-Te system in its ordered state was explained. Moreover the characteristics of the other phases which appear during the annealing processes were also discussed in the present article.
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This paper is concerned with the fabrication of (Fe,Co)-Si-B amorphous magneto-strictive wire which attracts strong attention as a new sensor material. First, we put the ingot of (Fe
$\sub$ 1-x/Co$\sub$ x/)$\sub$ 77/Si$\sub$ 8/B$\sub$ 15/ composition into quartz tube. Then, under the condition of 400MHz and 8kW, we melt and mix the in-got in the high frequency induction furnance. After that, we obtain the magnetostrictive wire of 100∼150$\mu\textrm{m}$ in diameter by injection and rapid quenching within the high rotating water. Finally, we find that the wire is under the amorphous state. -
정운조;조재철;박계춘;정해덕 1.1
Structural characteristics in Se thin film fabricated by EBE method had been studied. Se thin film was deposited with noncrystalline until substrate temperature of 100$^{\circ}C$ . But Se film was grown with monoclinic at substrate temperature of over 150$^{\circ}C$ . Lattice constants of it were as follow: a=12.76[${\AA}$ ], b=9.15[${\AA}$ ], c=10.4[${\AA}$ ]. Finally, after heat-treatment at 150$^{\circ}C$ for 15 min with substrate temperature of 100$^{\circ}C$ , noncrystalline Se was proved to be hexagonal. Lattice constants of it were as follow: a=4.27[${\AA}$ ], c=4.83[${\AA}$ ]. -
Kim, Myong R. 1.2
Recent progress in disk media based on the phase-change optical recording technology are reviewed. Some technical issues underlying phase-change optical storage with an emphasis on the media cyclability and compatibility will be also described in the present article. -
The fabrication and analytical expression for the temperature dependent capacitance characteristics of inverted staggered hydrogenerated amorphous silicon thin film transistors(a-si :H TFT) from 303k to 363k were presented. The results show that the experimental capacitance-voltage characteristics at several temperatures are easily measured. Capacitance increased exponentially by gate voltage increase and decreased by temperature increase. C/C(max) ratio decreased at higher temperature, C/C(min) ratio increased at higher temperature.
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We have studied the anisotropic dispersion force effects for surfaces alignment of liquid crystals (LCs) on rubbed polystyrene (PS) surfaces by unidirection. In microphotographs of the textures, we obtained the nematic (N) LCs are shown to align in both direction parallel and Perpendicular to the rubbing for region up to medium rubbing, however to align in the direction perpendicular to the rubbing for strong rubbing legion. We suggest that the anisotropic dispersion force is very important rather than macro-surface groove effect to uniform alignment of LCs. We also measured the temperature dependence of extrapolation length of 5CB on rubbed PS surfaces for strong rubbing. It is shown that the polar anchoring strength of 5CB is very weak on rubbed PS surface compared to the rubbed polyimide (Pl) surface.
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In this work, a scaling methodology to scale down to or below 0.1
$\mu\textrm{m}$ is presented, considering a current process technology. 0.12$\mu\textrm{m}$ nMOSFET's with both good performance and reliability is designed by this methodology -
The wavelength selectivity in grating-assisted optical waveguide couplers is studied using a matrix method to analyse optical filter characteristics. The matrix method is extended to both 2-system modes and all guided system modes. The influence of fundamental design parameters on the performances of the optical filters by waveguide couplers is discussed.
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1wt% Pt/MoO
$_3$ gas sensors for detecting H$_2$ gas were fabricated by the pressed pellet method and surface structures of Pt/MoO$_2$ were investigated by TEM and XRD. It was observed that as the calcination temperature is increased, the overlayers of MoO$_3$ on Pt are produced, but the Cl content in PtCl$\_$ x/ are decreased. H$_2$ gas sensing properties in N$_2$ ambient and in air ambient were investigated, respectively, and Pt/MoO$_3$ had high sensitivity at low working temp ; 7.8% at 50$^{\circ}C$ , 97.7% at 100$^{\circ}C$ , 97.1% at 150$^{\circ}C$ when the specimens are treated at 400$^{\circ}C$ , and 99.6% at 150$^{\circ}C$ when they are treated at 200$^{\circ}C$ . It shows the development of a low-power type sensor is possible by using Pt/MoO$_3$ . -
As electrode materials like as Cu-Pb, Cu-Bi, WC-Ag, W-Ag for vacuum circuit breaker have high chopping current or bad insulation-recovery characteristics, it can affect induction machinery like as transformer and motor. To produce low surge electrode material, it have been suggested Co-Ag-Te electrode which were infiltrated with Ag-Te intermetallic compound into sintered Co matrix in vacuum. In this paper, we would like to represent that production method and microstructure of Co-Ag-Te electrode material in each condition. The microstructure and characteristics of Ag-Te intermetallic compound and Co-(Ag-Te) electrode were investigated by using optical microscope, SEM, XRD, EPMA.
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Surface modification like cone formation on Pulsed laser deposition (PLD) occurs in YBCO target surface irradiated by laser beam. Cone formation results in a reduction of deposition rate, so that it is significant obstacles to an efficient deposition process. With the change of various conditions such as the number of laser shot, target density, direction of incoming laser beam, we have systematically analyzed the modification of target surface. Because cones formed by beam-target interactions grow in direction of incoming laser beam, we have used the method of rotating the target position by 180
$^{\circ}$ with the same number and position of laser shot. Experimental results of losing the directionality and changing the shape of cones formed on laser irradiated YBCO target surface is obtained by the SEM image. Also, we have observed that the size of cones formed on target by pulsed laser became larger with increasing the number of laser shots. -
This paper deals with the prebreakdown phenomena of
$SF_{6}$ gap stressed by non-oscillating and oscillating impulse voltages in a strong inhomogeneous field disturbed by a fred needle shaped-protrusion on the earth-side electrode. The breakdown voltage-time characteristics were measured for both positive and negative polarities and over the gas pressure range of 0.1∼0.5 MPa, and the temporal developments of the 77breakdown were observed by a shunt of 50 n. The dependence of the leader stopping time on the gas pressure were obtained. The local field enhancement due to the space charges, which is produced by the streamer corona, has influence with the electrical breakdown of the test gap. The test streamer corona is oxy a necessary condition for the electrical breakdown and the subsequent ionization activities launch the leader at the local field region. -
In this study, dielectric and piezoelectric properties of 0.5PNN-(0.5-x)PZN-xPZT system ceramics with PZT mole ratio were investigated. As the amount of PZT increases, curie temperature was increased. The maximum of dielectric and piezoelectric constant was shoun at 0.3 mole of PZT amount. As a results, we have found that the structure of ceramics with PZT 0.3 mole was morphotropic phase boundary.
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Polymerization rate, transmittance, refractive index, and extinction coefficient of plasma polymerized tetramethydisiloxane (TMD) have been investigated. The rate of polymerization of TMD films increased nonlinearly with the discharge lower. The refractive indices of thin films varied from 1.40 to 1.43 and they also increased with increasing discharge power. Also, the extinction coefficient was about 0.2 and is independent of photon energy.
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Polyvinylidene fluoride(PVDF) thin films are fabricated by vapor deposition method and their dielectric characteristics are investigated. At electric field near 4MV/m, a phase transition occur with polar
${\alpha}$ . In accordance to increasing temperature, the dielectric relaxation of PVOF thin films show from 70Hz to 104Hz. This result correspond to Debye's theory[1]. Activation energy of PVDP thin film is 21Kca1/mo1. -
The thin films are fabricated by VDPM and its heat resistant characteristics are investigated using Thermogravimetry. About polyimide, there is a wide difference between 5% weight loss temperature of TG curve and 20,000hr. of life time by methode of ASTM D2307. Therefore, TGI can be obtained by thermogravimetric analysis of NEMA std. pub. NOREI-1974. The TGI was got 670, 674 and 585 at 20
$^{\circ}C$ , 40$^{\circ}C$ and 70$^{\circ}C$ , respectively. -
The static charges are generated by streaming electrification phenomena in 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. In this paper the effect of Additive on the electric conductivity of Insulating oil is studied. The variation of electric conductivity disappear when Additive is molten in insulating oil BTA(Benzotriazole) appear more variation of electric conductivity than that of SP-S10(Sorbitan mono-stearate). But the variation is not enough to decrease streaming electrification of insulating oil(
$\sigma$ >10$\^$ -12/[S/cm]). -
It is well shown that the metallophthalocyanine (MPcs) are sensitive to tonic gaseous molecules such as NO
$_2$ and also chemically and thermally stable. Therefore, lots of MPcs are studied for the potential chemical sensor for NO$_2$ gas using quartz crystal microbalance(QCM) or electrical conductivity. In this study, thin films of octa(2-ethylhexyloxy) copper-phthalocyaninc ware prepared by Langmuir-Blodgett method and characterized by using UV-VIS spectrascopy and cllipsometry. Transfer condition, film characterization, and preliminary results of current-voltage(I-V) characteristics of these films exposed to NO$_2$ gas as a function of film thickness will be discusscd. -
It is well known that the metallo-phthalocyanines (MPcs) are sensitive to toxic gaseous molecules such as NO
$_2$ and also chemically and thermally stable and it is recently reported that SnO$_2$ thin films have a selective sensitivity to NO$_2$ and SO$_2$ gas. Therefore, it is interesting to prepare phthalo-cyanine Langmuir-Boldgett(LB) films containing tin as a chemical sensor for NO$_2$ and SO$_2$ gas and test the selectivity with these tin containing LB films. First, in this study, ultra thin films of Octa (2-ethylhexyloxy) tin-phthalocyanine were prepared on various substrates by LB method.$\pi$ -A isotherm and transfer characteristics of these films were investigated. The formation of these films was determined by ellipsometry. Intrinsic current-voltage(I-V) characteristics of these films were also measured. -
The optical and the electrical properties of octadecylviologen-(TCNQ
$\^$ -/)$_2$ LB(Langmuir-Blodgett) films have been studied. The films were made at 25mN/m with Y-type formation using kuhn type apparatus. According to a study of UV/visible absorption spectra, DS C, ESR, and I-V characteristics depending on temperatures, there is an internal change in OV-(TCNQ$\^$ -/)$_2$ LB films near 350K. We have observed a status of Langmuir films using Brewster angle microscope at room temperature. -
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Electrical properties such as surface flashover discharge and discharge degradations of insulating materials for superconducting cable have been investigated. It is found that the surface voltage is proportional to /
$\^$ 0.7/(/: discharge length) in LHe(Liquid Helium). V-t characteristic LHe were a n=5.5 that was less than liquid N$_2$ . After applied AC voltage, the surface condition of polymer films were observed non-eroded area and eroded area. The eroded area is depending on the applied voltage. In case of LHe, the crack was observed. -
The doped n-type
$Al_{x}Ga_{1-x}Sb$ crystals were grown by the vertical Bridgman method at composition ratio x=0, x=0.1, x=02 respectively. The lattice constants of the$Al_{x}Ga_{1-x}Sb$ crystals were 6.096${\AA}$ , 6.097${\AA}$ , 6.106${\AA}$ at composition ratio respectively. The carrier concentration, the resistivity, and the carrier mobility measured by the Van der Pauw method at x-0 were n≡1 x$10^{17}$ $cm^{-3}$ ,$\rho$ ≡0.15${\Omega}$ -cm,${\mu}$ $_{n}$ ≡500$\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ at 300K. The carrier concentration, the resistivity, and the carrier mobility measured by the Van der Pauw method at x=0.1 were n≡2.96 x$10^{15}$ $cm^{-3}$ ,$\rho$ ≡103$\textrm{cm}^2$ $V^{-1}$ $sec^{-1}$ at 300K. -
In this paper ZnO Piezoelectric transducers were fabricated as follows, counter electrode (pt 99.9%) was deposited on the sapphire substrates by DC sputter method, and then piezoelectric layer (ZnO 99.999%) was deposited on the counter electrode according to the sputtering parameters, and then top electrode (pt 99.9%) was deposited on the piezoelectric layer by Electron Beam Gun Evaporator. Structural characteristic of deposited ZnO thin film was measured by XRD, SEM. Also, Frequency characteristic of ZnO transducer was analyzed theoretically and practically for input frequencies.
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BaTiO
$_3$ films in pure Ar atmosphere were prepared by RF sputtering method at low substrate temperature(100$^{\circ}C$ ). The structural and crystallographic properties were studied with deposition conditions and annealing methodes. Deposition rates and structural properties of BaTiO$_3$ thin filles were investigated by the SEM and X-ray diffraction. The chemical composition of BaTiO$_3$ thin films grown on Si(100) wafer was studied by tole EDS and EPHA. The optimised Ar pressure and RF power were 8[mtorr] and 180[W], respectively. The thickness of BaTiO$_3$ thin films deposited at optimised conditions was ∼3400[${\AA}$ ], and the dielectric constant of the thin films heat-treated at 750[$^{\circ}C$ ] for 1[hr] was 259. -
In order to investigate control factors to critical current density, Ag sheathed Bi2223 superconducting tapes were fabricated using PIT process. Optimizing the reduction ratio of rolling, critical current density 7f rolled Bi2223 tape could be improved with the value of 15,000 A/
$\textrm{cm}^2$ (77 K, zero field). The correlation between J$\_$ c/ and work inhomogeneity was revealed as a dependence of COV of measured oxide layer thickness. -
A Study on The Dielectric Characteristics in EPOXY Composites due to Variation of Network StructuresIn this paper it is researched a relation between network structures and electrical properties - especially dielectric characteristics with changing of network structure. It is resulted that the specimens which have single network structures have smaller dielectric loss than SIN specimens but have relatively larger dependency to variation of temperature and frequency. For that reason formation of structures is attained by introducing of SIN to insulating materials. therefore it is counted that introduction of multiple structure including SIN is necessary to improve heat proof and electrical properties.
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In order to investigate the electrical properties for transformer oils which contains a Pure sodium chloride, the dielectric properties is made researches. To measure the dielectric loss of specimen, a coaxial cylindrical liquid electrode is used, and its geometric capacitance is confirmed to 16[pF]. And the dielectric dissipation factor, tan
$\delta$ , is measured by using the Video Bridge 2150. The thermal static oven with an automatically static temperature controller is used so as to support specific temperature to the specimen. This experiments for measuring the dielectric lass is performed at 20-120[$^{\circ}C$ ] in the temperature range, 30∼1.5x10$\^$ 5/[Hz] in the frequency range and 300∼1500[mV] in the voltage range. The result of experiment for the movement of carrier and the physical constants to contribute dielectric properties of specimen with a pure sodium chloride. -
In this paper, the volume resistivity of transformer oil is made researches so that the electrical properties for transformer oil is investigated. The specimen is produced by the irradiation of electron beam classified into the low dose, such as 0.5[Mrad], 1[Mrad], 2[Mrad]. The effect of electron team irradiation is studied by investigating the electrical properties of dielectric liquid due to the difference of electron beam dose. To measure the physical properties of transformer oil, courier Transform-Infrared Spectroscopy is investigated. And the study far the electrical properties is made by measuring the volume resistivity of each specimen. By means of the result from this experiments, it is introduced that the movement of carrier to contribute to the volume resistivity on the electrical properties.
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Polytetrafluoroethylene is very suitable for insulation materials because of it's high thermal and chemical stability, high electrical resistance and low loss factor. But almost all kinds of pure fluoroplastic cannot endure long time in the high temperature arc environment breaking high voltage and current In this study, inorganic materials such as BN, TiO
$_2$ and Al$_2$ O$_3$ were filled in the polytetrafluoroethylene to improve arc resistance. The electrical properties, arc resistant properties and light reflectance of the composites were investigated. -
Mechanical properties of Plasma-Enhanced Chemical Vapor Deposited (PECVD) silicon nitride thin film was studied to determine the feasibility of the film as a passivation layer over the aluminum bonding areas of integrated circuit chips. Ultimate strain of the films in thicknesses of about 5 k
${\AA}$ was measured using four-point bending method. The ultimate strain of these films was constant at about 0.2% regardless of residual stress. Intrinsic and residual stresses of these films were measured and compared with thermal shock and cycling test results. Comparison of the results showed that more tensile films were more susceptible to crack- induced failure. -
Platinum thin films were deposited on Si-wafer by DC magnetron sputtering for RTD (Resistance Thermometer Devices). We investigated the physical and electrical characteristics of these films under various conditions, the input power, working vacuum, temperature of substrate and also after annealing these films. The deposition rate was increased with increasing the input power but decreased with increasing Ar gas pressure. The resistivity were decreased wish increasing the temperature of substrate and the annealing time at 1000
$^{\circ}C$ . At substrate temperature 300$^{\circ}C$ , input power 7(w/$\textrm{cm}^2$ ), working vacuum 5mtorr and annealing conditions 1000$^{\circ}C$ , 240 min we obtained 10.65${\mu}$ Ω$.$ cm, resistivity of Pt thin film closed to the bulk value. -
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 5h. 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, but the more$LiCo_{1-x}Ni_{x}O_2$ involve NI, the more hexagonal structure is not well formed. In the result of charge/discharge test, charge/discharge characteristic of$LiCo_{1-x}Ni_{x}O_2$ is similar to that of$LiCoO_2$ . Therefore,$LiCo_{1-x}Ni_{x}O_2$ is superior to$LiCoO_2$ for Li secondary battery -
We have investigated the effect of molecular structure of polymer of rubbed polyimide (PI) films for surface liquid crystal alignment. To obtain surface alignment effect of Polymer molecular structure, we measured the polar (out of plane-tilt) anchoring strength and surface ordering of 5CB on rubbed PI surfaces. We have found that the polar anchoring strength of 5CB is depend on the polymer molecular structure of these unidirectionally rubbed PI surfaces.
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In this paper, We intended to evaluate the characteristics of XLPE/EPDM interface which exists in the cable joint. The fault was mainly occurred in this interface. Thus we looked into the electrical characteristics through the conduction current and the breakdown test. Through from the experiment, we obtained the result that the conduction current in this interface flowed less than other dielectric materials, that the breakdown strength was higher and that the pressure dependance ㅐf the breakdown strength was higher.
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In this paper, we have tried to focus on the optimum conditions of crystal structure parameters on YBCO high Tc oxide-superconductor as an excel lent electronic parts. When we verify the characteristic improvement of superconductance and accurate reproduction and so forth, we have made use of RIETAN. We have varied the lattice constant with oxygen content from 6.0 to 7.0 as for transition of orthogonal structure and tetragonal structure for the superconductor. As the result of above, we have preyed that transition from orthogonal structure to tetragonal structure is made at the point of 6.6(oxygen content) by using the simulation.
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We had experiment using LB method that can fabricate molecular order ultra-thin film below 100
${\AA}$ . LB method has known as main technology of information society in 21C, because it is not only free orientation and alignment of molecular but also ability of thickness control as molecular order. In this paper, the fabricated condition and physical properties 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 analyzing and measuring electrical properties. Polyimide ultra-thin LB film capacitor was fabricated, ensured theoretically and experimentally its possibility in range of 10Hz∼lMHz through its frequency characteristics. -
Langmuir-Biodgett(LB) method is known as a unique method for preparing organic thin films, which can control thickness of the films in molecular level, and many kinds of ultra thin films of functional molecules have been prepared using this method. In this study, The organization of phospholipid monolayers on a water surface was investigated by means of displacement current measurement technique.
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Superconducting current lead is one of the promising applications of the oxide high-Tc superconductors, because they have the advantage of decreasing heat conduction to low temperature region, comparing with a conventional cooper alloy lead. High critical current density is a key factor for the applications such as current lead. (Bi,Pb)
$_2$ Sr$_2$ Ca$_2$ Cu$_3$ O$\_$ x/ high Tc superconductor haute been investigated in terms of critical current density. Bi-2223 superconducting current lead made by CIP and solid state sintering process. Bi-2223 current lead that heat treated at 836$^{\circ}C$ for 240 h in 1/13 P$\_$ O$_2$ / had over 150 A/$\textrm{cm}^2$ of critical current density at 77K. We knew that the superconducting properties of tube type current leads were better than rods type of them. And we investigated the relation of Bi-2223 formation and heat treatment condition by XRD and SEM analysis. -
In this paper, We studied polyethylene thin film to evaluate the effects of crystal structure on breakdown properties and the dielectric strength on the condition of impurity free. Bielectric strength of the finn obtained with self healing method that is able to test repeatedly on the same sample is about 3.58 MV/cm at 0.73
$\mu\textrm{m}$ . The film shows outstanding crystal domain an\ulcorner crystal structure. The size of spherulites obtained reach 150-200$\mu\textrm{m}$ in diameter. -
The thermally stimulated currents(TSC) are measured to know the behaviour of charging particles of epoxy composites at the temperature range of -160∼200[
$^{\circ}C$ ] and to prove the variation according to curing time in this study. It is confirmed that the peak amplitude is inversely proportional to the curing time, and TSC are reduced is and T$\sub$ m/ is moved to high temperature side according to the curing time because carboxyl radical is formed by thermal oxidation and motility becomes lack. -
Directional coupling optical switch which on the LiNbO
$_3$ substrate is fabricated by using proton exchange method and self-aligned method. Proton exchange of proton diffusion method was applied to pattern a waveguide on LiNbO$_3$ substrate. The annealing at 400[$^{\circ}C$ ] was caroled out to control waveguide width and depth. The process of proton exchange was done at 150[$^{\circ}C$ ] for 120[min], 200[$^{\circ}C$ ] for 60[min] and annealing process was done at 400[$^{\circ}C$ ] for 90[min], 400[$^{\circ}C$ ] for 60[min]. The high speed directional coupling optical switch has very good figures of merits:the measured high frequency power were achieved. -
The electrochemical behavior of Ru complex and PD complex monolayer, deposited on conductive substrate by the Langmuir-Blodgett(LB) technique as monolayer and multilayer, has been studied by cyclic voltammetry. Monolayer films show stable reversible state. Atomic resolution imaging of LB highly-conductive, environmently stable organic films has been obtained by atomic force microscopy (AFM) showing their closely packed structure,
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Polyphenylenediamine(PPD) film was prepared with dimethylsulfoxide after the synthesis of PPD by chemical polymerization. The molecular structure of conductive polymer synthesized were discussed by using SEM, FT-IR, NMR. The electrical conductivity measurements were carried out at room temperature. The electrical conductivity which was obtained from electrical instrument was 1.98
${\times}$ 10$\^$ -2/ S/cm at ambient temperature. -
A.C. and D.C. characteristic of TiO
$_2$ added SnO$_2$ are investigated to study the electrical properties. The electrical inductivity increases as TiO$_2$ content increase. The doer effect of TiO$_2$ is crucial role for the increase of electrical conductivity. The frequency-dependent ac inductivity increases with the increase of TiO$_2$ contents at low frequency region. However, at high frequency region, the difference of ac conductivity is very small. Impedance spectrums are consist of the one semicircle. Therefore, the sizes of semicircle decreases with increasing the TiO$_2$ contents. -
The electrical inductivity decreases when the content of NiO is used within 1 at% and increases when it's used more than that. Impedance spectrum seems to be one semicircle. The size of semicircle increases when the content of NiO is sued within 1 at% and decreases when it's used mor than that.
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In this paper, we investigated the optical coupling characteristics for
$K^{+}$ ion-exchanged diffused channel waveguide by using coupled-mode equations. In this case, the optical-power-dividing was observed at the waveguide-type optical coupler with 3[$\mu\textrm{m}$ ] line-width and, 6[$\mu\textrm{m}$ ] separation between channel waveguides in which interaction lengths were 1 and 3[mm], respectively, On the basis of that we deformed simulation for$Ag^{+}$ ion-exchanged diffused channel waveguide. As a result of simulation, the optical-power-dividing was shown at the waveguide-type optical coupler wish 3[$\mu\textrm{m}$ ] line-width, 6[$\mu\textrm{m}$ ] separation between channel waveguides and 0.11[mm] interaction length. -
The surface properties after plasma etching of TiW solutions using the chemistries of BCl
$_3$ and SF$\_$ 6/ gases with varying mixing ratio have been investigated using X-ray photoelectron spectroscopy. The elements of C, Cl, F, O and S are observed on the etched TiW films. After plasma etching with SF$\_$ 6/ gas, Ti-S bond are detected on the samples and Ti-S bond makes a role of passivation layer that surpresses Ti-O formation. After plasma etching wish BCl$_3$ gas, Ti are easily removed but W are hardly etched. As a results, W/Ti are increased on the etched sample. -
Dielectric properties were investigated at Mn doped 0.17(
$Ba_{0.53}$ ,$Pb_{0.47}$ )0-$0.16Nd_2O_3$ -$0.67TiO_2$ system in microwave frequency. It was observed that dielectric constant of 90.1, quality factor of 1320 (at 3.8GHz) and temperature coefficient of resonance frequency 2.3 ppm/$^{\circ}C$ for 0.5wt% Mn doped 0.17($Ba_{0.53}$ ,$Pb_{0.47}$ )0-$0.16Nd_2O_3$ -$0.67TiO_2$ system in sintering condition$1290^{\circ}C$ /2hr. The quality factor increase due to the compensation effect of Mn ions yp to 0.5wt% and the decrease due to the interface relaxation effect. The temperature coefficient of resonance frequency increases to negative direction with increasing the amounts of Mn. -
In this study, we have fabricated all solid state electrochromic devices using WO
$_3$ film as the working electrode, V$_2$ O$\_$ 5/ film as the counter electrode and PEO-LiClO$_4$ -PC film as the solid electrolyte. The WO$_3$ thin films for working electrode and V$_2$ O$\_$ 5/ thin films for counter electrode were deposited onto ITO glass by vacuum evaporation and were shown good electrochromic and state properties after 1x10$\^$ 5/ cycles. PEO-LiClO$_4$ -PC polymer electrolyte can easily be formed into thin films, do not absorb in the visible region of the light. Therefore, such electrolyte have electrochromic properties suitable for large-scale all solid-state electrochromic devices. All solid-staeelectrochromic devices fabricated in this polymer electrolyte have optical modulation of 20%∼30% at 1.5 V. -
In this Study, the capacitance-voltage properties of the (Sr
$\_$ 1-x/$.$ Ca$\_$ x/)$\_$ m/TiO$_3$ (0.05$\leq$ x$\leq$ 0.2, m=0.996, 1, 1.004) ceramics were investigated. The results of the capacitance-voltage measurements indicated that the grain boundary was composed of the continuous insulating layers. The capacitance is almost unchanged below about 20[V] but it decreases slowly about 20[V]. The thick of the effective depleation layer was calculated by using the average grain size, it was in the range of 760∼3400[${\AA}$ ]. -
Mitsumasa Iwamoto;Wu, Chen-Xu 6.1
Starting from the Debye theory of rotational Brownian motion equation, we derive an expression for explaining the generation of Maxwell displacement current (MDC) across single monolayers on a material surface. The orientational order parameter and the dielectric relaxation the of monolayers are derived. Based on fille analyses developed here, we examine the MDC across phospholipid monolayers with thermal stimulation due to the change in the spontaneous polarization, and the generation of MDC from 4-cyano-4\`-5-alkayl-biphenyl(5CB) Langmuir-film at the onset of transition by monolayer compression -
이창희;구자룡;김태완;김정수 6.2
The NO$_2$ GAS-detection characteristic of CuTBT (Copper-tetra-tert-butylphtha1ocyanine) LB films were investigated through a study of current-voltage (I-V) characteristics with a variation of number N of interdigital electrodes (N=1∼25). A concentration of 200ppm NO$_2$ gas was used. It was found that a conductance G increases monotonically as the number of interdigital electrode increases, and a sensitivity$\Delta$ G ($\Delta$ G=G$\_$ gas//G$\_$ air/) is at least higher than 50 and stable. As far as a sensitivity is concerned, the sensitivity when N=26 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrodes affects the currents, sensitivity and stability.