Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)
The Korean Institute of Electrical and Electronic Material Engineers
- Annual
2002.11a
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To achieve the global planarization, CMP Technology has been used to the next generation semiconductor process, and the study made tremendous progress up to date. As the device demension shrinked, CMP Technology has been applied in a various way and more people interested in this field to simplify the process. To attain the goal for safer 0.13um or below 10 nano process, many of those expected task must be solved. By describing this current CMP process issue and future trend for the CMP planarization process, It personally hope that this paper would help to the people who has concerns for the next generation semiconductor manufacturing industry in common.
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Three different ZnO nanomaterials (nanobelts, nanorods, and nanowires) were synthesized at three different substrate temperatures from the thermal evaporation of ball-milled ZnO powders at
$1380^{\circ}C$ . Transmission electron microscopy (TEM) revealed that the ZnO nanobelts are single crystalline with the growth direction perpendicular to the (010) lattice planes, and that the ZnO nanorods and nanowires are single crystalline with the growth directions perpendicular to the (001) and (110) lattice planes, respectively. In photoluminescence (PL), the peak energy of near band-edge (NBE) emission was determined for nanobelts, nanorods, and nanowires. -
In this paper, We have studied the CMP (chemical mechanical polishing) characteristics of diluted slurry by adding of raw alumina abrasive and annealed alumina abrasive. As a experimental results, we obtained the comparable slurry characteristics compared with original silica slurry in the view point of high removal rate and low non-uniformity. Therefore, we can reduce the cost of consumables(COC) of CMP process for ULSI applications.
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Boron Phosphide films were deposited on the glass substrate at the low temperature,
$550^{\circ}C$ ,$480^{\circ}C$ , by the reaction of$B_{2}H_{6}$ , with$PH_{3}$ using CVD. The reactant gas rates were 50 cc/min and 20 cc/min for$B_{2}H_{6}$ , 50 cc/min and 40 cc/min for$PH_{3}$ and$1.5\ell$ /min for$N_{2}$ carrier gas. The films were annealed for 1hour, 3hours in$N_{2}$ ambient at$550^{\circ}C$ and$400^{\circ}C$ . The deposition rate was$1000{\AA}$ /min and the refractive index of film was 2.6. From results of XRD measurement the films have the preferred orientation of (1 0 1). For as deposited the film, the data of VIS spectrophotometer show 75.49%, 76.71% for 1hr-annealed and 86.4% for 3hrs-annealed. From AFM datas the surface condition of obtained films are was shown$73{\AA}$ ,$88.9{\AA}$ and$220{\AA}$ for as-deposited, for 1hr-annealed and for 3hr annealed, respectively. -
HgTe quantum dots were synthesized in aqueous solution at room temperature by colloidal method. The synthesized materials were identified to be zincblende cubic structured HgTe quantum dots by X-ray diffraction and transmission electron microscopy image revealed that these quantum dots are agglomerate of a individual particle. The colloidally prepared HgTe quantum dots have the sphere-like shape with a diameter of approximately 4 nm. The optical properties of the HgTe quantum dots were investigated with photoluminescence(PL). The PL appears in the near-infrared region, which represent a dramatic shift from bulk HgTe behavior. The analytic results revealed that HgTe quantum dots have the broad size distribution, as PL emission spectrum covers the spectral region from 900 to 1400 nm. In this study, the factors affecting PL of HgTe quantum dots and particle size distributiont are described. 會Ā᐀ 䁇?⨀ 젲岒 Ā 㰀 會Ā㰀 顇?⨀ 끩 Ā ㈀ 會Ā㈀ ?⨀ 䡪 ఀ Ā ᐀ 會Ā᐀ 䡈?⨀ Ā ᐀ 會Ā᐀ ꁈ?⨀ 硫 ᜀ Ā 저 會Ā저 ?⨀ 샟ග ऀ Ā 저 會Ā저 偉?⨀ 栰岒 ఀ Ā 저 會Ā저 ꡉ?⨀ 1岒 Ā 저 會Ā저 J?⨀ 惝ග Ā 會Ā 塊?⨀ ග 嘀 Ā 切 會Ā切 끊?⨀ ⣟ග Ā 搀 會Ā搀 ࡋ?⨀ 큭킢 Ā 저 會Ā저 恋?⨀ 桮킢 Ā 저 會Ā저 롋?⨀ ⣅沥 ࠀ Ā ࠀ 會Āࠀ ၌?⨀ 샅沥 Ā 저 會Ā저 桌?⨀ 壆沥 ሀ Ā 저 會Ā저 쁌?⨀ o킢 瀀 ꀏ 會Ā ᡍ?⨀ 棤좗 Ā Ā Ā 會ĀĀ 灍?⨀ å좗 Ā Ā Ā 會ĀĀ 졍?⨀ 飥좗 Ā Ā Ā 會ĀĀ ⁎?⨀ ?ꆟ ᤀ
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In this paper, the characteristics of channel hot electron (CHE) injection for the write operation in a NOR-type SONOS flash memory with common source line were investigated. The thicknesses of he tunnel oxide, the memory nitride, and the blocking oxide layers for the gate insulator of the fabricated SONOS devices were
$34{\AA}$ ,$73{\AA}$ , and$34{\AA}$ , respectively. The SONOS devices compared to floating gate devices have many advantages, which are a simpler cell structure, compatibility with conventional logic CMOS process and a superior scalability. For these reasons, the introduction of SONOS device has stimulated. In the conventional SONOS devices, Modified Folwer-Nordheim (MFN) tunneling and CHE injection for writing require high voltages, which are typically in the range of 9 V to 15 V. However CHE injection in our devices was achieved with the single power supply of 5 V. To demonstrate CHE injection, substrate current (Isub) and one-shot programming curve were investigated. The memory window of about 3.2 V and the write speed of$100{\mu}s$ were obtained. Also, the disturbance and drain turn-on leakage during CHE injection were not affected in the SONOS array. These results show that CHE injection can be achieved with a low voltage and single power supply, and applied for the high speed program of the SONOS memory devices. -
Recently, CMP (chemical mechanical polishing) technology has been widely used for global planarization of multi-level interconnection for ULSI applications. However, COO (cost of ownership) and COC (cost of consumables) were relatively increased because of expensive slurry. In this paper, we have studied the possibility of recycle of reused silica slurry in order to reduce the costs of CMP slurry. The post-CMP thickness and within-wafer non-uniformity(WIWNU) were measured as a function of different slurry composition. As a experimental result, the performance of reused slurry with annealed silica abrasive of 2 wt% contents was showed high removal rate and low non-uniformity. Therefore, we propose two-step CMP process as follows In the first-step CMP, we can polish the thick and rough film surface using remaked slurry, and then, in the second-step CMP, we can polish the thin film and fine pattern using original slurry. In summary, we can expect the saving of high costs of slurry.
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Ferroelectric Mg-doped SBT and Ti-doped SBT were successfully deposited on Pt/Ti/
$SiO_2/Si$ substrate by using a sol-gel solution coating method. The solutions were prepared through out adding the metal alkoxide solutions to SBT solution. The typical hysteresis loop of the films was obtained at 5V. The measured$2P_r$ value were$16.50{\mu}C/cm^2$ for SBT,$18.98{\mu}C/cm^2$ and for Mg-doped SBT, and$17.10{\mu}C/cm^2$ for Ti-doped SBT at an applied voltage of 5V, respectively. And it is found that the leakage current densities are less than$10^{-7}A/cm^2$ when applied voltage is less than 10.8MV/cm, which indicates the excellent insulating characteristics. -
ZnO nanowires were coated conformally with aluminum oxide (
$Al_{2}O_{3}$ ) material by atomic layer deposition (ALD). The ZnO nanowires were first synthesized on a Si (100) substrate at$1380^{\circ}C$ from ball-milled ZnO powders by a thermal evaporation procedure with an argon carrier gas without any catalysts; the length and diameter of these ZnO nanowires are$20\sim30{\mu}m$ and$50{\sim}200$ nm, respectively.$Al_{2}O_{3}$ films were then deposited on these ZnO nanowires by ALD at a substrate temperature of$300^{\circ}C$ using trimethylaluminum (TMA) and distilled water ($H_{2}O$ ). Transmission electron microscopy (TEM) images of the deposited ZnO nanowires revealed that 40nm-thick$Al_{2}O_{3}$ cylindrical shells surround the ZnO nanowires. -
폴리머 애자용 Shed 재료의 전기방전에 대한 열화내성과 표면발수성은 제품의 장기성능에 있어서 가장 중요한 물성들이다. 그러나 무기보강재의 첨가량이 많아 무결점 성형성을 만족하도록 하기 위해서 Process Oil의 사용이 불가피한데 사용하는 오일의 종류와 양에 따라 옥외절연물의 장기성능에 영향을 주는 표면발수성이나 방전내성은 크게 차이가 나는 것으로 밝혀져 있다. 본 논문에서는 화학적 구조와 점도가 다른 몇 종의 hydroxy silicone oil(HS 오일)을 혼련 (kneading) 하는 과정에 첨가하여 이들 오일의 종류와 양이 고무의 기본적인 물성, 발수성, 방전열화내성, 내트래킹성 등에 어떻게 영향을 주는가를 조사하였다. 코로나 처리시간에 따라서 접촉각의 저하정도와 코로나 처리 후 경과시간에 따른 발수성의 회복특성을 조사하였다. HS 오일의 접도에 따라 초기발수성, 발수성 회복특성의 차이가 많았다. 점도가 낮을수록 초기 발수성 저하는 크며 회복속도는 빠른 반면 점도가 높을수록 초기 발수성 저하는 작은 반변은 발수성 회복속도는 다소 느리게 나타났다 내트래킹성 결과는 점도가 높을수록 우수한 특성을 보였다. 결론적으로 폴리머 애자용 실리콘고무의 컴파운딩에서 실리콘오일의 선택은 성형작업성, 발수성회복특성, 열화내성 외에 가격 등을 고려하여 최적화가 필요하다.
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In this paper, the volume resistivity properties of silicone rubber investigated due to temperature dependence. And the measurement of volume resistivity is measured from 1, 5 and 10 minutes when the each applied voltage, for example, DC 100[V], 250[V], 500[V] and 1000[V], is applied. according to the step voltage application method. As a result, The volume resistivity is higher high voltage than low voltage at the room temperature, but is higher low voltage than high voltage at high temperature.
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In this study we attempted to diagnose the distribution of nitrogen plasma density generated using PECVD(plasma enhanced chemical vapor deposition). The distribution of plasma density formed in a PECVD chamber were measured by DLP2000. The experiment results showed that the plasma density is related to RF power and gas flow rate. As RF power gets higher, the plasma density linearly increased. And the experimental results revealed that a pressure in chamber affects plasma density.
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The preliminary results on the application of optical fiber sensor(OFS) for locations of ultrasonic signals in underwater are presented and analyzed. The OFS utilizing the principle of Sagnac interferometry was designed and the hollowed cylindrical mandrel wound by single mode optical fiber was used as sensing component. The ultrasonic signal source was simulated by the PZT actuator operated with function generator. It has been shown that the OFS could detect the signals less affected by ultrasonic path comparing to conventional acousto-electric sensor and accurate location of ultrasonic signal could be carried out using two OFSs.
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The electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. but Increasing awareness of electromagnetic compatibility(EMC) issues in lighting application, the problems of interference generation by electrodeless fluorescent lighting system have been highlighted. In this paper, Maxwell 2D finite element analysis program(ansoft) is used to obtain electromagnetic properties associated with the coil and nearby structures. and also evaluated Flux, B, H, by changing the input current.
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Currently small and accurate dosimeters are on the rise. In this study, the feasibility and energy dependency of the electret dosimeter that made of PET (polyethylene terephtalate) were observed by irradiating 4, 6, 15 MV photon beams from the clinical linear accelerator to develop a dosimeter for the clinical field.
$10{\times}10cm$ field size of the photon beams were irradiated to the electret dosimeter where the 2.5 cm depth in the polystylene phantom from 100 cm SSD, while 300 DCV was applied to the electret dosimeter. The result showed that the absorbed dose was proportional to the charge linearly, and the volume of a dosimeter could be reduced and the signals were high enough. According to this study, it was found that the polymer electret detector could be produced as a large quantity with a small cost and showed the feasibility of a realtime measurement. -
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In this paper, a single phase driven piezoelectric motor design was presented for linear motion. Two metal/ceramic composite actuators, a piezoelectric ring which was bonded to a metal endcap from one side, were used as the active elements of this motor. The motor was composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. Motors with 30.0[mm] and 35.0[mm] diameter were studied by finite element analysis and experiments. As results, the maximum speed of motor was obtained at resonant frequency. When the applied voltage of the motor increased, the speed was increased. Also, bidirectional motion of the motor was achieved by combining two motors which have different resonant frequency.
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In this paper,
$3^{rd}$ overtone mode energy-trapped filter using modified$PbTiO_3$ system ceramics was manufactured to apply for intermediate frequency SMD-type filter with the variations of splitted electrode size. To investigate the effects of splitted electrode size on filter characteristics of$3^{rd}$ overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size($b{\times}d$ ) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5mm, respectively. And then, SMD-type ceramic filter were fabricated with the size of$3.7{\times}3.1mm$ . With the variations of b size, insertion loss, 3dB bandwidth and 25dB stop bandwidth showed nearly constant value, but with the variations of d size, insertion loss, 3dB bandwidth, selectivity(shape factor) decreased.⨀ က ?⨀ Ⴣ?⨀ Ⴣ?⨀ ꞻꎀ ̀က ꮻꎀ ༀ 뮻ꎀ ᠀ Ȁ 햻ꎀ Ā ힻꎀ Ȁ ?ꎀ ̀ ?ꎀ Ȁ ꎀ Ā ꎀ Ā ꎀ Ā ꎀ Ā ꎀ Ѐ Ȁ ꎀ ࠀ ꎀ ഀ ڼꎀ ഀ ᒼꎀ ᮼꎀ 䈀 Ȁ Ȁ 悼ꎀ ऀ 檼ꎀ ഀ Ȁ 禼ꎀ ഀ 螼ꎀ ऀ Ȁ Ȁ 鎼ꎀ ഀ Ȁ ꊼꎀ ഀ 낼ꎀ ࠀ 즼ꎀ Ԁ 쾼ꎀ ܀ ힼꎀ -
In recent year, BLT(
$Bi_{3.25}La_{0.75}Ti_{3}O_{12}$ ) has been one of promising substitute materials at the ferroelectric random access memory applications. We manufactured$Bi_{3.25}La_{0.75}Ti_3O_{12}$ Target with a ceramic process. The BLT target was sintered at${1100^{\circ}C}$ for 4 hours. Using RF magnetron sputtering, a deposited BLT thin films were estimated about ferroelectric properly as a functions of post annealing temperatures. The BLT thin films showed a promoted ferroelectric characteristics at the post annealied sample of${700^{\circ}C}$ . This sample exhibited the (117) preferred crystal orientation, current density of$3{\times}10^{-8}A/cm^2$ , a remanent polarization of$8{\mu}C/cm^2$ and a coercive field of 42.1 KV/cm respectively. -
The conditions of zone-melting method such as a sample travel speed in a furnace, content of Nd422, control of melting temperature, and heat-treatment with/without Ar gas for
$NdBa_{2}Cu_{3}O_{7-\delta}$ superconductor was optimized, As a results, a$NdBa_{2}Cu_{3}O_{7-\delta}$ sample with a surface area of$25mm^{2}$ showed a good superconducting properties when its travel speed was 6 mm/h, The improvement of superconductivity added with 10~20 wt% of Nd422 phase increasing pinning effect was also shown. The critical current density,$J_{c}$ was remarkable affected by the condition of heat-treatment temperature of$NdBa_{2}Cu_{3}O_{7-\delta}$ superconductor with/without Ar ambient gas. -
전력선 통신 blocking filter용 자심 재료를 개발하기 위해서 MnO 24 mol%, ZnO 25 mol% and
$Fe_{2}O_{3}$ 51 mol% 의 기본조성에$MoO_{3}$ ,$SiO_{2}$ , CaO를 첨가하여$1350^{\circ}C$ 에서 대기압 상수 A를 7.8롤 고정하고 소결하여 미세구조를 제어하였으며 기본 조성에$MoO_{3}$ 400 ppm,$SiO_{2}$ 100 ppm and CaO 200 ppm을 첨가한 경우 평균 입경$25{\mu}m$ 의 균일한 결정립으로 구성된 미세구조를 얻었고 기공의 감소에 의한 치밀화로$4.98g/cm^{2}$ 의 고밀도화가 이루어 졌다. 또한 소결체의 균일한 미세구조와 고밀도화로 인해서 8221(${25^{\circ}C}$ , 1 KHz) 의 가장 높은 투자율 특성을 나타냈다. 시편의 온도가 증가함에 따라 투자율이 증가되어${110^{\circ}C}$ 에서 13904의 거대 투자융이 측정되었고, 코일의 인가주파수가 1 KHz에서 1 MHz까지 증가됨에 따라 최고${102^{\circ}C}$ 까지 시편 온도가 상승하였다. 가장 높은 투자율 특성을 나타낸 ferrite 코어를 사용하여 단상 및 3상용 블로킹 필터의 감쇄율을 측정한 결과 현재 국내의 전력선 통신용 주파수 대역으로 규정되어 있는 10 KHz ~ 450 KHz 대역에서 각각 -46.46 dB와 -73.9 dB의 최고 값을 얻었다. -
The BSCCO superconductor materials of using Self-propagating High-temperature Synthesis (SHS) were studied. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product. In this paper as an effort for fabricating the SHSed BSCCO superconductor powder SHS method was considered to application in the synthesis of superconducting materials.
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We prepared
$Co_{77}Cr_{20}Ta_{3}$ thin film with Facing Targets Sputtering Apparatus. which can deposit a high quality thin film CoCrTa magnetic layer for Perpendicular magnetic recording media. In order to obtain Good Crystal orientation of CoCrTa thin films. We prepared Thin Films on slide glass substrate. The thickness of Buffer-layer were varied from 10 to 50 nm and Magnetic layer thickness fixed 100[nm]. input current was varied from 0.2[A] to 0.5[A]. Substrate temperature was varied from room temperature to${250^{\circ}C}$ respectively. The crystal orientation of the CoCrTa film were examined with XRD. Introduce Buffer-layer thin films showed improvement of dispersion angle of c-axis orientation (${\Delta\theta}_{50}$ ). -
The electrophoretic deposition (EPD) technique have been applied to fabricating superconducting films and wires in former researches of our Lab. However, the particles of EPD films were usually deposited random1y on the metal substrate, the vertically combined a.c and d.c fields were applied to the EPD electrodes for orienting and densifying the particles of high
$T_{c}$ superconducting deposition film on the substrate metal. Therefore, the surface states of EPD films by this combined fields could be oriented and affect to the electric properties increasing of superconducting films. The proposed method modified by a.c. assisted field to the conventional electrophoresis system was suitable to obtain improved properties with particle oriented deposition and densification. -
Chung, Jong-Kab;Cho, Woo-Sung;Choi, Chang-Hun;Ju, Byeong-Keon;Park, Sun-Woo;Kim, Chul-Ju;Rho, Seung-Ryong;Kim, Young-Cho 111
To understand the discharge characteristics in AC-PDP, it is necessary to study on the wall charge behavior. But, it is difficult to measure the wall charge directly. In this paper, the V-Q Lissajous' figure is used to measure the wall charge indirectly and analyze the wall charge behavior. With the V-Q Lissajous' figure, the discharge characteristics of AC-PDP are studied according to vary driving conditions, such as the frequency, pulse duty ratio, and rising & falling time. As a result, the V-Q Lissajous' figure is used to measure the discharge characteristics of the AC-PDP. It is confirmed that firing initial voltage and firing final voltage for discharge are effected by the aboved variables. Related with the wall voltage generation, it is thought that the difference of the slope at the V-Q Lissajous' figure is caused by charged ions inside the dielectric layer. -
Khatkar, S.P.;Taxak, V.B.;Han, Sang-Do;Kim, Byeong-Kwon;Jung, Young-Ho;Park, Jo-Yong;Liang, Y.;Myung, Kwang-Shik 116
A different route to the synthesis of$Eu^{3+}$ - activated matrices such as$YAlO_{3}$ and$GdAlO_{3}$ and luminiscent properties of these compounds, were studied. The new route (Combustion method) consist of the redox reactions between the respective metal nitrates and urea in a preheated furnace at${500^{\circ}C}$ . The Phosphor thus obtained were then heated at${1000^{\circ}C}$ for 2-3 hours to get better luminiscent properties. The incorporation of$Eu^{3+}$ activator in these phosphors were checked by luminiscence investigations. Scanning electron microscopy (SEM) studies were carried out to understand surface morphological features and the particle size. X-ray energy dispersive analysis (EDAX) was also performed for the qualitative analysis of the phosphors. -
In this study it had an excellent optical characteristic, it followed in the creation rate and the refractive index regulation to the ease. Chalcogenide produced the
$As_{45}Se_{45}Te_{10}$ thin film and the$MgF_{2}$ thin film. It measured thin film plan simulation, and the thin film has a 1 -dimensional photonic band gap. The chalcogenide$As_{45}Se_{45}Te_{10}$ thin film was measured with the fact that it has a high refractive index (2.6~2.9). The$As_{45}Se_{45}Te_{10}$ and$MgF_{2}$ thin film, have a high refractive index and a low refractive index, it used a simulation and planed period 5-pairs structure, the result was from 500nm to 800nm. It will be able to confirm the characteristic which most of the incidence light reflects, the He-Ne (632.8nm) laser was irradiated in the thin film which stabilized the thin film.$As_{45}Se_{45}Te_{10}$ (high refractive index layer: H) and$MgF_{2}$ (low refractive index layer: L) results which plans the thin film with glass/LHLHLLHLHL/air structure, 632.8nm against transmitance, increased a lot. An application possibility with the filter against a specific wave length was confirmed. -
LC aligning capabilities and the variation of pretilt angles with ion beam irradiation on the a-C:H thin films, and electro-optical (EO) performances of the ion beam aligned twisted nematic (TN)-liquid crystal display (LCD) with oblique ion beam exposure on the a-C:H thin film were studied. A high pretilt angle of
$3.5{^{\circ}}$ via ion beam irradiation on the a-C:H thin film was measured. Also, the LC pretilt angle decreased due to the increase in surface roughness at over 2 min of IB exposure time. It is considered that this roughness increase due to increasing IB exposure time that generated destroy of oriented rings of atoms related to LC alignment. An excellent voltage-transmittance (V-T) curve of the ion beam aligned TN-LCD was observed with oblique ion beam exposure on the a-C:H thin film for 1 min. Also, a faster response time for the ion beam aligned TN-LCD with oblique ion beam exposure on the a-C:H thin film for 1 min can be achieved. Finally, the residual DC property of the ion beam aligned TN-LCD with ion beam exposure of 1 min on the a-C:H thin film is almost same as that of the rubbing aligned TN-LCD on a PI surface. -
In this paper, we used the V-Q Lissajous‘ figure for studying on the plasma discharge characteristics of the 42 inches AC-PDP. From the V-Q Lissajous‘ figure, we could observe exactly the driving conditions that the self-erasing discharge takes place. At the time, the total wall charges lessened by self-erasing discharge was calculated quantitatively. Beside of the just observation of self-erasing discharge and calculation of the charges lessened, we could find out the optimum driving conditions for inducing the maximum wall charges accumulated on the dielectric layer with measuring the Wall voltage from the V-Q Lissajous' figure.
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MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in the low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field(
$H_{k}$ ) as a function of a thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and$320^{\circ}C$ respectively for 2 hours. Magnetic properties of film are measured by using a MH loop tracer. Its magnetic permeability of a film is measured over the frequency range 1 MHz to 750MHz. And, it was examined on the permeability and impedance to design the MI sensor which acts at 50MHz by thickening a CoZrNb film relatively, and fabricated the MI sensor which acts at the 50MHz. -
Previous valves have initial gap problem, high voltage or high pressure problem. In this paper, various micro valves with free floating structure have been fabricated and tested to solve the initial gap and high pressure problems. The paper presents how to etch Parylene-C which is a valve cap material without A1 mask layer. The maximum flow-rate of fabricated micro valve is
$118{\mu\ell}$ /min with$370{\mu}m$ orifice size and the leakage at the initial and reverse pressure is not observed. -
In this study, we prepared ZnO/glass and
$ZnO/SiO_{2}/Si$ thin film by Facing Targets Sputtering (FTS) system for Film Bulk Acoustic Resonator (FBAR). When the ZnO thin film applied to piezoelectric thin film, it requires good c-axis preferred orientation. And c-axis orientation has a remarkable difference with preparation conditions. Therefore, c-axis orientation must be significantly evaluated according to changing deposition conditions. Moreover, in order to prepare ZnO thin film with good crystallographic properties and progressive of efficiency of product process, the ZnO thin film should have to prepared as low temperature as possible. In this work, we prepared ZnO thin films on slide glass and$SiO_{2}/Si$ substrate. And the crystallographic characteristics of ZnO thin films on sputtering conditions were investigated by alpha-step and X-ray diffraction. -
In this study, we evaluated the dilute HF Cleaning to reduce residual defects made by W CMP process. But, One point we should focus is It should not effect to metal thin film reliability. The purpose of this test is to verify barrier metal damage during HF cleaning and based on this result we get rid of slurry residue defect which is main defect of W CMP process for the better yield.
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AP/RPCVD를 이용하여
$650^{\circ}C$ 의 저온에서 실리콘-게르마늄의 선택적 단결정 성장 (Selective Epitaxy Growth: SEG) 을 수행하였다. 본 실험에서는$SiH_4$ ,$GeH_4$ 그리고 HCl 가스를 사용하여 잠입시간 동안 실리콘-게르마늄막을 성장시키고 연속해서 HCI 가스만을 주입하여 산화막 위에 형성되어진 작은 결정입자들을 식각하는 공정을 반복적으로 수행하였다. HCl 의 식각에 의해 한 주기의 잠입기 후에도 다시 잠입기가 존재함을 확인하였고, 이 성장법을 통하여 한 주기의 잠업시간 동안 증착할 수 있는 두께 이상으로 실리콘-게르마늄막의 선택적 성장이 가능하였다. 이는 저온 선택적 실리콘-게르마늄 성장 시 RPCVD에서 보이는 낮은 선택성과$SiH_4$ 의 짧은 장입시간으로 인해 원하는 두께까지 확보하기 힘든 단점을 극복한 것이다. 선택성을 향상시키기 위해 실리콘-게르마늄 증착중 주입된 HCI의 유량에 따라 잠입시간과 증착속도에 영향을 주었으며, 연속공정을 위한 식각공정은 20sccm의 HCI을 20초간 주입하여 선택성을 유지하였다. 또한 보론 불순물의 첨가가 선택적으로 성장되는 박막의 결정성에 미치는 영향도 분석되었다. -
Eu-doped lead zirconium titanate
$Pb_{1.1}(Zr_{0.3}Ti_{0.7})O_{3}$ thin films on the Pt/Ti/$SiO_2$ /Si substrates prepared by a metalorganic decomposition (MOD) method. The effect on the structural and electrical properties of the films measured according to Eu content. Eu-doping altered significantly the dielectric and ferroelectric properties. The remanent polarization and coercive field decreased with increasing the concentration of Eu content. The dielectric constant and dielectric loss of the film decreased with increasing Eu contents. The 3 mol% of Eu-doped PZT thin film showed large remanent polarization and the fatigue characteristic of the film did not change up to$10^9$ switching cycles. -
Ferroelectric
$YMnO_{3}$ thin films were etched with$Ar/Cl_{2}$ and$CF_{4}/Cl_{2}$ inductivly coupled plasma (ICP). The maximum etch rate of$YMnO_{3}$ thin film was$300{\AA}/min$ at a$Ar/Cl_{2}$ gas mixing ratio of 2/8, a RF power of 800 W, a dc bias of 200 V, a chamber pressure of 15 mTorr, and a substrate temperature of${30^{\circ}C}$ . From the X-ray photoelectron spectroscopy (XPS) analysis , yttrium not only etched by chemical reactions with Cl radicals, but also assisted by Ar ion bombardments in$Ar/Cl_{2}$ plasma. In$CF_{4}/Cl_{2}$ plasma, yttrium are remained on the etched surface of$YMnO_{3}$ and formed of nonvolatile YFx compounds Manganese etched effectively by chemical reactions with Cl and F radicals. From the X-ray diffraction (XRD) analysis, the (0004) diffraction peak intensity of the$YMnO_{3}$ thin film etched in$Ar/Cl_{2}$ plasma shows lower value than that in$CF_{4}/Cl_{2}$ plasma. It is indicates that the crystallinty of$YMnO_{3}$ thin film is more easily damaged by the Ar ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products. -
We investigated structural and electrical properties of Metal-Oxide-Semiconductor(MOS) structure using Hafnium
$oxide(HfO_{2})$ as high-k gate dielectric material.$HfO_{2}$ films are ultrathin gate dielectric material witch have a thickness less than 2.0nm, so it is spotlighted to be substituted$SiO_{2}$ as gate dielectric material. In this paper We have grown$HfO_{2}$ films with pt electrode on P-type Silicon substrate by RF magnetron sputtering system using$HfO_{2}$ target and oserved the property of semiconductor-oxide interface. Using pt electrode, it is necessary to be annealed at${300^{\circ}C}$ . This process is to increase an adhesion ratio between$HfO_{2}$ films with pt electrode. In film deposition process, the deposition time of$HfO_{2}$ films is an important parameter. Structura1 properties are invetigated by AES depth profile, and electrical properties by Capacitance-Voltage characteristic. Interface trap density are measured to observe the interface between$HfO_{2}$ with Si using High-frequency(1MHz) C-V and Quasi - static C-V characteristic. -
Ji, Hee-Hwan;Bae, Mi-Suk;Lee, Hun-Jin;Oh, Soon-Young;Yun, Jang-Gn;Park, Sung-Hyung;Wang, Jin-Suk 167
The influence of Si surface damage on Ni-silicide with TiN Capping layer and the effect of$H_2$ anneal are characterized. Si surface is intentionally damaged using Ar Sputtering. The sheet resistance of NiSi formed on damaged silicon increased rapidly as Ar sputtering time increased. However, the thermal stability of Ni-Si on the damage silicon was more stable than that on at undamaged Si, which means that damaged region retards the formation of NiSi. It was shown that$H_2$ anneal and TiN capping is highly effective in reducing NiSi sheet resistance. -
The barium strontium titannate (BST) thin films were etched in
$CF_{4}/Ar$ inductively coupled plasma (ICP). The high etch rate obtained at a$CF_{4}(20%)/Ar(80%)$ and the etch rate in pure argon was twice higher than that in pure$CF_{4}$ . This indicated that BST etching is sputter dominant process. It is impossible to avoid plasma-induced damages by the energetic particles in the plasma and the nonvolatile etch products. The plasma damages were evaluated in terms of leakage current density, residues on the etched sample, and the changes of roughness. After the BST thin films exposed in the plasma, the leakage current density and roughness increases. In addition, there are appeared a nonvolatile etch byproductsand from the result of X-ray photoelectron spectroscopy (XPS). After annealing at${600^{\circ}C}$ for 10 min in$O_{2}$ ambient, the increased leakage current density, roughness and nonvolatile etch byproducts reduced. From the this results, the plasma induced damage recovered by annealing process owing to the relaxation of lattice mismatches by Ar ions and the desorption of metal fluorides in high temperature. -
Electrical characteristics of the Si-O superlattice diode as a function of annealing conditions have been studied. The nanocrystalline silicon/adsorbed oxygen superlattice formed by molecular beam epitaxy (MBE) system. Consequently, the experimental results of superlattice diode with multilayer Si-O structure showed the stable and good insulating behavior with high breakdown voltage. This is very useful promise for Si-based optoelectronic and quantum device as well as for the replacement of silicon-on-insulator (SOI) in ultra high speed and lower power CMOS devices in the future, and it can be readily integrated with silicon ULSI processing.
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We studied the characteristics of polishing pad, which can apply W CMP process for global planarization of multilevel interconnection structure. Also we investigated the effects of different sets of polishing pad. The purpose of this experiment is the cost reduction by the increase of pad life time and decrease of cycle time and slurry usage with new pad. Especially we studied the effect of polishing pad for CMP process by this experiment of polishing pad that is consumables material during CMP process. We expecting the increase of process throughput and improvement of device manufacturing yield because we can choose optimum polishing pad through this result.
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자기정렬구조의 실리콘-게르마늄 이종접합 트랜지스터에서
$f_{max}$ 를 높이기 위한 방안으로 베이스의 저항 값을 감소시키고자 외부 베이스에 실리콘 및 실리콘-게르마늄 박막을 저온에서 선택적으로 성장할 수 있는 방법을 연구하였다. RPCVD를 이용하여$SiH_{2}Cl_{2}$ 과$GeH_{4}$ 를 소스 가스로 하고 HCI을 첨가하여 선택성을 향상시킴으로써$675\sim725^{\circ}C$ 의 저온에서도 실리콘 및 실리콘-게르마늄의 선택적 에피성장이 가능하였다. 고온 공정에 주로 이용되는$SiH_{2}Cl_{2}$ 를 이용한 실리콘 증착은$675^{\circ}C$ 에서 열분해가 잘 이루어지지 않고 HCl의 첨가에 의한 식각반응이 동시에 진행되어 실리콘 기판에서도 증착이 진행되지 않으나$700^{\circ}C$ 이상에서는 HCI을 첨가한 경우에 한해서 선택성이 유지되면서 실리콘의 성장이 이루어졌다, 반면 실리콘-게르마늄막은 실리콘에 비해 열분해 온도가 낮고 GeO를 형성하여 잠입시간을 지연하는 효과가 있는 게르마늄의 특성으로 인해 선택성이나 증착속도 모두에서 유리하였으나 실리사이드 공정시에 표면으로 게르마늄이 석출되는 현상 등의 저항성분이 크게 작용하여 실리콘-게르마늄막 만으로는 외부 베이스에의 적용은 적절하지 않았다. 그러나 실리콘막을 실리콘-게르마늄막 위에 Cap 층으로 증착하거나 실리콘막 만으로 외부 베이스에 선택적으로 증착하여 베이스의 저항을 70% 가량 감소시킬 수 있었다. -
The MFIS capacitors were fabricated using a metalorganic decomposition method. Thin layers of
$CeO_2$ were deposited as a buffer layer on Si substrate and BLT thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated. X-ray diffraction was used to determine the phase of the BLT thin films and the quality of the$CeO_2$ layer. The morphology of films and the interface structures of the BLT and the$CeO_2$ layers were investigated by scanning electron microscopy. The width of the memory window in the C-V curves for the MFIS structure is 4.78 V. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory FETs with large memory window. -
In this study, the etching of Au thin films have been performed in an inductively coupled CF4/Cl2/Ar plasma. The etch properties were measured as the CF4 adds from 0 % to 30 % to the Cl2/(Cl2 + Ar) gas mixing ratio of 0.2. Other parameters were fixed at a rf power of 700 W, a dc bias voltage of 150 V, a chamber pressure of 15 mTorr, and a substrate temperature of
$30^{\circ}C$ . The highest etch rate of the Au thin film was 370 nm/min at a 10 % additive CF4 into Cl2/(Cl2 + Ar) gas mixing ratio of 0.2. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. From x-ray photoelectron spectroscopy (XPS) analysis, the intensities of Au peaks are changed. There is a chemical reaction between Cl and Au. Au-Cl is hard to remove on the surface because of its high melting point and the etching products can be sputtered by Ar ion bombardment. We obtained the cleaned and steep profile. -
CdTe quantum dots(QDs) were synthesized in aqueous solution by colloidal method. Photoluminescence(PL) spectra of the synthesized CdTe QDs revealed the intensity of PL peaks was stronger as the condensation time was longer. This result was thought because annealing effect by thermal energy transferred during condensation eliminated defects which act as traps and recombination centers in CdTe particle. PL intensity has stron dependence of Te precursor concentration. It confirmed the ratio of Te ion to Cd ion added during synthesis affected the particle size and size distribution of the CdTe QDs. Finally, the synthesized CdTe QDs were identified to be cubic structured CdTe quantum dots by X-ray diffraction(XRD).
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Bae, Mi-Suk;Kim, Yong-Goo;Ji, Hee-Hwan;Lee, Hun-Jin;Oh, Soon-Young;Yun, Jang-Gn;Park, Sung-Hyung;Wang, Jin-Suk;Lee, Hi-Deok 198
In this paper, the dependence of Ni-silicide properties such as sheet resistance and cross-sectional profile on the dopants have been characterized. There was little dependence of sheet resistance on the used dopants such as As, P,$BF_{2}$ and$B_{11}$ just after RTP (Rapid Thermal Process). However, the silicide properties showed strong dependence on the dopants when thermal treatment was applied after formation of Ni-silicide.$BF_{2}$ implanted sample shows the best stable property, while$B_{11}$ implanted one was thermally unstable. The main reason of the excellent property of$BF_{2}$ sample is believed to be the retardation of Ni diffusion by the flourine. -
The photoluminescence (PL) characteristics of the silicon-oxygen(Si-O) superlattice formed by molecular beam epitaxy (MBE) were studied. To confirm the presence of the nanocrystalline Si structure, Raman scattering measurement was performed. The blue shift was observed in the PL peak of the oxygen-annealed sample, compared to the hydrogen-annealed sample, which is due to a contribution of smaller crystallites. Our results determine the right direction for the fabrication of silicon-based optoelectronic and quantum devices as well as for the replacement of silicon-on-insulator (SOI) in high-speed and low-power silicon MOSFET devices in the future.
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The purpose of this research was to find influence of compounding materials on electrical properties of silicone rubber such as tracking characteristic. The tracking characteristic was tested through controlling the ATH, a widely use anti-tracking agent. Regarding the particle size and coupling agent of ATH, compound silicone rubber with ATH of coupling agent and larger diameter showed better anti-tracking properties. It can be included that ATH of coupling agent use vinyl silane, dispose of tracking characteristic was achieve excellant results.
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This thesis is contents on the crystal grown by the solide phase method at
$925^{\circ}C$ with orthorhombic structure that$LiMnO_{2}$ active material synthesised with precurse$Mn_{2}O_{3}$ and$LiOH.H_{2}O$ material to get three voltage level. The porosity analysis of the grown crystal in secondary batteries$LiMnO_{2}$ thin film is$1.323E+02\AA$ of the average pore diameter of powder particles and its structure to be taken the pore diameter was prepared. Adding voltage area to get properties of charge and discharge of which experiment result of$LiMnO_{2}$ thin film area 2.2V~4.3V, current and scan speed were 0.1mAh/g and$0.2mV/cm^{2}$ respectively, and properties of the charge and discharge to be got optimum experiment condition parameter and density rate of Li for analyze that unit discharge capacity with metal properties is 87mAh/g was 96.9[ppm] at 670.784[nm] wavelength, and density rate of Mn analyzed 837[ppm] at 257.610[nm]. It can be estimated the quality of thin film that wrong cell reject from the bottle of electrolyte. The results of SEM and XRD were the same that of original researchers. -
Much quantity of anti-tracking agent, ATH is added to the silicone rubber for the protection of silicone rubber against surface discharge. Hydrophobicity recovery properties of silicone rubber could be different by the content, surface treatment state and particle size of ATH. Because hydrophobicity of silicone rubber is depend much on the surface state of ATH. In this paper, the properties of silicone rubber is investigated according to the addition of different particle size of ATH to the silicone rubber. Hydrophobicity recovery properties and arc resistance of silicone rubber were investigated according to the addition of different particle size of ATH. Hydrophobicity recovery properties of silicone rubber were evaluated by the measurement of contact angle.
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Experimental study for radiation stress properties of EPDM cable for nuclear power plant was investigated. Samples of EPDM are fabricated as hot press, then radiation rays irradiated 0~100Mrad and measured radiation properties in the voltage range of 0~10KV. Voltage-current and capacitance characteristics of linear and log curves and the relationship of current due to irradiation of radiaition rays are discussed.
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In this paper, we have investigated the physical properties and electrical conduction properties of polyethylene terephthalate film due to temperature variation, and the measurement of volume resistivity used to highmegohm meter is measured from 1 to 10 minutes when the specimen applied the voltage accroding to the step voltage appling method. From FT-IR spectrum as an analysis of physical properties, the strong absorption in wavenumbers
$1019[cm^{-1}]$ ,$1266[cm^{-1}]$ and$1752[cm^{-1}]$ observed by the C=O and benzene ring. From the analysis of DSC, the crystalline melting points of the specimen observed in the temperature$80[^{\circ}C]$ and$263[^{\circ}C]$ , respectively. -
In this paper, we estimated the insulation properties of cross-linked polyethylene (XLPE) for ultra-high voltage cable. we have studied the dielectric characteristics of XLPE due to frequency and temperature variation. The dielectric characteristics were measured in the temperature range from
$25[^{\circ}C]$ to$120[{^{\circ}C]}$ . Also we measured in the voltage range of 1[V] to 20[V] according to the step voltage application method. From FT-IR spectrum as an analysis of physical properties, a strong absorption in wavenumbers 700 to$730[cm^{-1}]$ ,$1456[cm^{-1}]$ and 2700 to$3000[cm^{-1}]$ observed by the methyl groups$(CH_{2})$ . From the analysis of DSC, the crystalline melting points of the specimen observed in the temperature$60[^{\circ}C]$ and$106.58[^{\circ}C]$ . -
Recently developed liquid silicone rubber (LSR) can be cured by platinum catalyzed additional hydrosilylation mechanism and has the advantage of no byproduct compared to traditional millable peroxide curing silicone rubber. We investigated the characteristics of dielectric breakdown of silicone rubber and adhesion properties between semi-conductive LSR and insulating LSR for high voltage application of pre-molded joint (PMJ). In order to understand the dielectric breakdown characteristics, we used the sheet samples and the paired type rogowski insert electrode system. The breakdown strength and adhesion strength of LSR (E-3) were superior to those of several silicone rubbers. Adhesion strength could be improved by curing at high temperature without post-curing process or enhanced by post-curing process. When LSR (E-3) was cured at
$(150^{\circ}C{\times}10min$ semi-conductive )${\times}$ ($175^{\circ}C{\times}10min$ insulation), it showed the high breakdown strength with low standard deviation, and good adhesion strength. In this results, we could apply this process to the fabrication of PMJ without post-curing. -
Surface states of silicone polymer treated by plasma were investigated by the analysis by x-ray photoelectron spectroscopy (XPS) and surface voltage decay. Plasma treatment causes the silica-like oxidative layer, which is confirmed with XPS, and lowers surface resistivity with increasing the plasma treatment time. Using the decay time constant of surface voltage, the calculated surface resistivity was compared with the value directly measured by a voltage-current method. A good agreement between two methods was obtained. In addition, we estimated the thermal activation energy for surface conduction, Based on our results, we could understand the relationship between surface chemical states and surface electrical properties.
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반도체 소자의 고속화, 고접적화에 따라 집적회로의 최소 선폭이 감소할수록 device 의 신호지연, 잡음 및 전력소모 등이 증가하는 문제점이 있다. 이러한 문제점을 개선하기 위해서 저유전율의 층간 절연막이 절대적으로 필요하다. 본 실험에서는 KrF laser 조사를 이용한 표면개질 방법으로 다공성 절연막의 박막특성의 향상을 시도하였다. 다공성 절연막을 층간 절연막으로 응용할 경우 반도체 공정 적용성을 향상시키기 위하여 다공성 절연막의 표면개질이 필요하다. 표면개질 전후의 유전율 변화는 박막을 MIM구조로 측정하였고 화학 구조의 변화는 time-of flight secondary ion mass spectrometry(TOF-SIMS)를 이용하여 관찰하였다. 다공성 실록샌 물질의 pore로 인해서 생긴 누설전류 및 흡습 문제를 개선시키고 유전율을 감소시킬 수 있는 것을 알 수 있었다.
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NdBaCuO thin films were prepared on
$SrTiO_{3}$ substrates by RF magnetron sputtering. These as-grown films were classified into 3type. The resistivity of the deposited films are usually lower than of the YBCO film. The Tc (onset) and Tc (R=0) in the optimized thin films are as high as 90 and 80K, respectively. These as-grown films are highly uniform and semi-trans parent and have a room temperature resistivity of$0.3m{\Omega}cm$ . -
In the electrophoresis for fabrication of a superconducting wire and film, the enough deposition and formal sustain of a film condition affect to superconducting state of samples. In this paper, a superconducting film was fabricated with various suspension solution such as acetone, buthanol, and ethanol. As a results, the best deposition condition with d.c 250 V and a.c 25 V of applied voltage, and 90 sec of applied time for BSCCO superconducting film by electrophoresis was investigated.
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BSCCO thin films are fabricated by an ion beam sputtering method, and sticking coefficients of the respective elements are evaluated. The sticking coefficient of Bi element in BSCCO film formation was observed to show a unique temperature dependence; it was almost a constant value of 0.49 below about
$730^{\circ}C$ and decreased linearly over about$730^{\circ}C$ . In contrast, Sr and Ca, displayed no such remarkable temperature dependence. This behavior of the sticking coefficient was explained consistently on the basis of the evaporation and sublimation processes of$Bi_{2}O_{3}$ . It was concluded that Bi(2212) thin film constructs from the partial melted Bi(2201) phase with the aid of the liquid phase of$Bi_{2}O_{3}$ . -
The critical currents of sintered
$YBa_{2}Cu_{3}O_{6.5+\delta}$ were measured as the variables with the corrosive time in the humid air. The corrosive process was studied by means of the current changes. Ag coating on the textured YBCO and polytetrafluoroethylene (PTFE) coating on the sintered YBCO were prepared. The critical current densities of different YBCO samples with and without coatings were compared. Both Ag coating and PTFE coating can well protect YBCO from moisture and$CO_{2}$ . -
There is great interest in developing magnetoresistance(MR) sensor, using ferromagnetic, electrically non-magnetic conducting and antiferromagnetic films, especially for the use in weak magnetic fields. Here, we report single and Wheatstone-bridge type of MR sensors made in Si(001)/NiO(
$300{\AA}$ )/NiFe bilayers. Angular dependence of MR profiles was measured in Si(001)/NiO($300{\AA}$ )/NiFe($450{\AA})$ films as a function of an angle between current and applied field direction, also, linearity was determined. AMR characteristics of single MR sensors was well explained with single domain model. Good linearity in$45^{\circ}$ Wheatstone-bridge type of MR sensors consisting of 4 single MR sensors made in Si(001)/NiO($300{\AA}$ )/NiFe($450{\AA})$ was shown in the range of about${\leq}{\pm}5$ Oe. -
An ozone condensation system is evaluated from the viewpoint of an ozone supplier for oxide thin film growth. Ozone is condensed by the adsorption method and its concentration is analyzed by three methods; ultraviolet absorption, thermal decomposition and Q-mass analyzing methods. Thermal decomposition method is found to be available to the concentration evaluation from dilution to highly condensed ozone. The highest ozone concentration condensed by the adsorption method is evaluated to be 97 mol%
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The goal of the research is to study and describe a new stressed state of High Temperature Superconducting (High-Tc) YBCO Films, to create of SQUIDs (Superconducting Quantum Interference Device) on the bases of these Films with maximal sensitivity. The experimental investigation of the stressed films grown by laser ablation method and its properties, the fabrication of the dc-SQUIDs with maximal sensitivity on the bases of the stressed YBCO films were carried out. The stressed film having the value of the critical current density
$J_{c}=3{\cdot}10^{5}A/cm^{2}$ was the more stable than others. -
An ozone condensation system is evaluated in the viewpoint of an ozone supplier for oxide thin film growth. Ozone is condensed by the adsorption and distillation method. Then their concentrations are analyzed by three methods; ultraviolet absorption, thermal decomposition and Q-mass analyzing methods. Thermal decomposition method is found to be available to the concentration evaluation from dilution to highly condensed ozone. The highest ozone concentration condensed by the adsorption method is evaluated to be 96 mol%. The ozone is supplied for a sufficiently long time to grow oxide thin films.
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$Bi_{2}Sr_{2}CaCu_{2}O_{x}$ was prepared by the conventional method of solid state reaction and SHS method. The samples were annealed in different atmosphere in order to examine the influence of atmospheres on the carbon contents in the$Bi_{2}Sr_{2}CaCu_{2}O_{x}$ compound. The lowest carbon content in$Bi_{2}Sr_{2}CaCu_{2}O_{x}$ could be attended when the sample was annealed in$O_{2}$ at$800^{\circ}C$ for 100 hours. The$CO_{2}$ in air pollute the samples and increase the carbon content in the sintering process. The critical current density of the$Bi_{2}Sr_{2}CaCu_{2}O_{x}$ samples will decrease with the increasing carbon contents in the samples. The impurity carbon will deposit in the grain boundary, which makes critical current density lower. -
In this study, the effects of
$Nb_{2}O_{5}$ addition on microstructure and piezoelectric characteristics of PNW-PMN-PZT ceramics were investigated. As$Nb_{2}O_{5}$ addition amount is increased, grain size is gradully decreased. At 0.3wt%$Nb_{2}O_{5}$ addition composition ceramics, maximum density, tetragonality and piezoelectric characteristics were obtained. -
The
$BaTi_{4}O_{9}$ ceramics with CoO(0.5wt%) were prepared by the conventional mixed oxide method. The sintering temperature and time were$1350^{\circ}C$ , 3hr., respectively. The structural properties were investigated with sintering temperature by XRD. Also the microwave dielectric properties of the$BaTi_{4}O_{9}$ ceramics were studied. According to the X -ray diffraction patte구 of the$BaTi_{4}O_{9}$ ceramics with CoO(0.5wt%), the orthorhombic$BaTi_{4}O_{9}$ structure was appeared. In the case of$BaTi_{4}O_{9}$ ceramics with CoO(0.5wt%), dielectric constant$(\varepsilon_{r})$ , quality factor$(Q{\times}f_r)$ and temperature coefficient of resonant frequency$(\tau_{f})$ were 40.8, 43,270 and$2.5ppm/^{\circ}C$ , respectively. ࠀ ࠀ Ѐ 耀 Āࠀ 耀 耀 ࠀ က @ Ā Ā Ȁ Ѐ Ā က Ѐ က ࠀ 耀 Ȁ @ ࠀ Ѐ Ѐ Ȁ耀 @ 䀀 က 䀀 Ѐ 耀 Ȁ @ ࠀ Ѐ Ѐ က Ȁ ȀЀ Ā က 蠀 -
An alkoxide-based sol-gel method was used to fabricate
$(Pb_{x},Sr_{1-x})$ TiO3 (PST) thin films on a Pt/Ti/SiO2/Si substrate, and the dielectric properties of the PST thin films were investigated as a function of the Pb/Sr composition for use in tunable microwave device applications. The dielectric properties of the PST films were strongly dependent on the Pb/Sr ratio. The dielectric constant and dielectric loss of the PST films increased with increasing Pb content, and the figure of merit (FOM) reached a maximum value of 27.5 at a Pb/Sr ratio of 4:6. The tunability increased with increasing Pb content. The dielectric constant, loss factor, and tunability of PST (50/50) thin films were 404, 0.023, and 51.73%, respectively. From the result, the PST films with good dielectric properties are useful candidates for tunable microwave device. -
Transducer for linear ultrasonic motor with symmetric and anti-symmetric modes was studied. The transducer was composed of two Langevin-type vibrators that cross at right angles with each other at tip. In order to excite two vibration modes, two Langevin-type vibrators must have 90-degree phase difference with each other. As a result, tip of transducers moves in elliptical motion. In this paper, elliptical trajectory of transducer was analyzed by employing the finite element method.
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In this paper, a hexagon-type piezoelectric transformer was investigated to increase the output power. The length of its side was 14mm and 17.5mm, respectively. The piezoelectric ceramics was composed to PZT-PMN-PSN. This composition showed the characteristics which had an about 1500 of the mechanical Q-factor, 0.55 of the electromechanical coupling coefficient,
$320{\times}10^{-12}C/N$ of the piezoelectric constant$d_{31}$ , 0.3 % of the dissipation factor, etc. The voltage step-up ratio increased with increasing the load resistance,$R_{L}$ , so it reached 80 with$R_{L}$ of$1M{\Omega}$ and was proportion to the length of side of the hexagon-type piezoelectric transformer. Also, the output power increased with increasing the size of the hexagon-type piezoelectric transformer. -
The effects of Mo doping on Electrical Properties of
$BiNbO_{4}$ Ceramic Thick Film Monopole AntennaWe fabricated thick film monopole antennas using Mo-doped$BiNbO_{4}$ ceramics and investigated their electrical properties as a function of the Mo-doping concentration. Compared with undoped$BiNbO_{4}$ ceramics, 10 at.% Mo-doping improved microwave dielectric properties of ceramics by increased sintered density as well as decreased space charge density. Further increase in the Mo-doping concentration caused formation of$Bi_{2}MoO_{6}$ phases, resulting in deterioration of the microwave characteristics. The gain and bandwidth of the ceramic monopole antenna were also greatly affected by the Mo-doping concentration. When Mo-doping concentration was 10 at%, highest gain of ~0.7dBi with lowest bandwidth of 30% at 2.3GHz was obtained. -
This paper presents design and analysis of stator which is vibration source of ring-type ultrasonic motor. The stator were designed for 9th flexural vibration mode. Designed stator was simulated by FEA for changing its materials. As results, the resonance frequencies of stators were changed by Poisson's ratio and density. And higher displacement were obtained by using the materials of low Young's modulus. Using the results, can easily design and manufacture the stator of ring type ultrasonic motor. And we suppose that it can save the time and finances.
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Ferroelectric
$Sr_{0.3}Ba_{0.7}Nb_{2}O_{6}$ (SBN30) thin films were deposited on Pt/Ti/$SiO_{2}$ /Si(100) substrates by ion beam sputtering. During annealing treatment at$750^{\circ}C$ , poling was attempted by applying dc voltage bias across polished surfaces. Phase relation, microstructure and crystallization behavior were examined using XRD and FE-SEM. Ferroelectric hysteresis characteristics were also determined where both remanent polarization and coercive values decreased with the increase of bias voltage. The measured remanent polarization and coercive field values at 5 V and 10 V bias were$36{\mu}C/cm^2$ ,$10{\mu}C/cm^2$ and 100kV /cm, 80kV /cm, respectively. -
비철금속 습식 제련용 고효율 장수명의 양극을 개발하기 위해서 산소 과전압이 낮은
$MnO_{2}$ 를 촉매로 사용하여 반도체 산화물계의 산소선택성 전극을 제조하고 산화물 coating층의 미세구조와 전기화학적 특성을 분석하였다. PVDF :$MnO_{2}$ 의 함량비플 1 : 1 에서 1 : 40까지 정량적으로 변화시켰고, 용제의 점도에 지배적인 영향을 미치는 DMF의 함량을 각각의 고정된 PVDF :$MnO_{2}$ 의 함량비에서 변화시켜 용제를 제조하였으며 4%$HNO_{3}$ 용액에 세척된 Pb전극을 1.5 mm/sec 의 속도로 5회 dipping 하였다. PVDF :$MnO_{2}$ = 1 : 6인 경우 PVDF의 양이 증가하고 DMF의 양이 감소할수록 피막층이 두꺼워지고 PVDF : DMF = 4 : 96인 경우 pb 전극의 피막층이 얇기 때문에 박리현상이 일어났으며 이는 산화물 용제의 낮은 점도 때문인 것으로 판단된다. 또한 PVDF : DMF = 10 : 90의 경우는 5회 dipping 하여 약$150{\mu}m$ 의 피막층을 형성하였다. PVDF : Mn02의 함량비가 1:1에서 1:6 까지는 DMF의 함량에 무관하게 전극 특성이 나타나지 않았지만$MnO_{2}$ 의 양이 상대적으로 증가하면 cycle 이 증가하더라도 거의 일정한 전류 값을 갖고$MnO_2$ 와 PVDF의 비가 20:1 이상의 조성에서는 균일한 CV 특성을 나타냈다 이는$MnO_{2}$ 가 효과적으로 촉매 작용을 한 것으로 판단되며 anodic polarization에 의한 산소 발생 과전압도 약 1.4V 정도로 감소되었다. -
Choi, Hae-Yun;Kwon, Jeong-Ho;Lee, Dae-Su;Kim, Il-Won;Song, Jae-Sung;Jeong, Soon-Jong;Lee, Jae-Shin 317
Piezoelectric properties of$(Pb_{1-x}Y_x)[(Ni_{1/3}Nb_{2/3})_{0.15}(Zr_{1/2}Ti_{1/2)})_{0.85}]O_{3}$ (x=0~0.05) ceramics were investigated, The stoichiometric PNN-PZT ceramics required the sintering temperature above$1100^{\circ}C$ , but the addition of$Y_{2}O_{3}$ in the PNN-PZT ceramic lowered the sintering temperature down to$1000^{\circ}C$ . In case of x=0.005, the electro-mechanical coupling$factor(K_p)$ , the piezoelectric$constant(d_{33})$ , and the maximum strain ratio of PNN-PZT ceramics sintered at$1000^{\circ}C$ were 53.1%, 395pC/N, and$2200{\times}10^{-6}$ respectively, A 30-layer piezoelectric actuator$(10{\times}10{\times}1.7mm)$ fabricated with the above material showed the maximum strain of$2.09{\mu}m$ under 100V DC bias. -
In this study, dielectric and piezoelectric properties of PSN-PZT Ceramic were investigated as a function of PNW substitution. With the increase of PNW substitution, teragonality, Curie temperature and mechanical quality factor were decreased but grain size and electromechanical coupling factor(kp) was gradully increased. At 4 mol [%] PNW substitution. maximum kp of 0.567 was shown.
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In this study, to develop the low temperature sintering ceramics for multilayer piezoelectric transformer,
$0.02Pb(Sb_{1/2}Nb_{1/2})O_{3}-0.13Pb(Ni_{1/3}Nb_{2/3}O_3-0.85Pb(Zr,Ti)O_{3}$ system ceramics were manufactured with the variations of sintering temperature between 1,090 and$1240^{\circ}C$ and its dielectric and piezoelectric characteristics were investigated. With increasing the sintering temperature, electromechanical coupling factor (kp) and mechanical quality factor(Qm) were decreased. At$1,180^{\circ}C$ sintered specimen showed maximum value of 0.535 electromechanical coupling factor (kp). On the other hand,. The specimen sintered at$1,180^{\circ}C$ showed the maximum value of${\varepsilon}r$ =1,571, Qm=1,181 respectively. -
The stability against DC accelerated aging stress of
$Dy_{2}O_{3}-doped$ $ZnO-Pr_{6}O_{11}-based$ varistor ceramics was investigated. The calculated nonlinear exponent$(\alpha)$ in varistor ceramics without$Dy_{2}O_{3}$ was only 4.9, whereas the$\alpha$ value of the varistors with$Dy_{2}O_{3}$ was abruptly increased in the range of 48.8 to 58.6. The varistor ceramics with$Dy_{2}O_{3}$ content of 1.0 mol% exhibited maximum${\alpha}$ , reaching 58.6, whereas they exhibited very poor stability. While, The varistor ceramics doped with 0.5 mol%$Dy_{2}O_{3}$ exhibited not only the high nonlinearity, which the${\alpha}$ is 55.3 and the leakage current is$0.1{\mu}A$ , but also the highest stability, which the variation rates of varistor voltage and nonlinear exponent are -0.8% and -14.3%, respectively, under DC accelerated aging stress,$0.95 V_{1mA}/150^{\circ}C/24h$ . -
Kwon, Jeong-Ho;Choi, Hae-Yun;Jeong, Yeon-Hak;Kim, Il-Won;Song, Jae-Sung;Jeong, Soon-Jong;Lee, Jae-Shin 334
In this study, the microstructure, dielectric and piezoelectric properties of$0.15Pb(Ni_{1/3}Nb_{2/3})O_3-0.85(PbZr_{0.5}Ti_{0.5})O_3$ (0.15PNN-0.85PZT) ceramics having compositions near the morphotropic phase boundary(MPB) was investigated with respect to the variation of$Y_2O_3$ and$Ga_2O_3$ addition amount. The dielectric properties increased and piezoelectric properties decreased with increasing the amount of$Ga_2O_3$ . The solubility limit of$Y_2O_3$ is 0.5mol% in this system. The electro-mechanical coupling factor$(K_p)$ and dielectric constant(${\varepsilon}_r$ ) were 58.6% and 1755 when the amount of$Y_2O_3$ are 0.5mol%. -
$(Ba_{1-x}Sr_{0.4}Ca_x)TiO_{3}$ (x=0.10, 0.15, 0.20) powders were prepared by the sol-gel method and BSCT thick films were fabricated by the screen-printing method. Their structural and dielectric properties were investigated with variation of composition ratio and$Al_{2}O_{3}$ doping contents. As results of the X-ray diffraction and microstructure analysis, the grain size of BSCT thick films was decreased with increasing$Al_{2}O_{3}$ amount. The thickness of BSCT thick films by 4-coating/drying is about$110{\sim}120{\mu}m$ . The tunability increased with decreasing Ca content, and the BSCT(50/40/10) specimen doped with 1.0wt%$Al_{2}O_{3}$ showed the highest value of 12.94% at 5kV /cm. -
As the size of chip components and module decreases, new patteming method for fine line and geometry is needed. So far, in LTCC(Low Temperature Cofired Ceramic) process, screen printing method has been used generally. But screen printing method has some disadvantages as follows. First, the geometry including line, vias, etc. smaller than
$100{\mu}m$ can't be evaluated easily. Second, the patterned dimension is different from designed value, which makes distortion in charactersitics of not only chip components but also modules. Thick film lithography has advantages of thick film screen printing process, low cost and thin film process, fine line feasibility. Using this method, the line with$30{\mu}m$ width and the geometry with expected dimension can be evaluated. In this study, the fine line with$35{\mu}m$ line/space is formed and the embedded capacitor with very small tolerance is developed using thick film lithography. -
Ferroelectric
$Bi_{4-x}Nd_{x}Ti_{3}O_{12}(BNdT)$ thin films with the composition(x=0.75) were prepared on$Pt/Ti/SiO_{2}/Si(100)$ substrate by metal-organic deposition. The films were annealed by various temperatures from 550 to$650^{\circ}C$ and then the electrical and structural characteristics of BNdT films were investigated for the application of FRAM. Electrical properties such as dielectirc constant, 2Pr and capacitance were quite dependent on the thermal heat treatment. The measured 2Pr value on the BNdT capacitor annealed at$650^{\circ}C$ was$56{\mu}C/cm^{2}$ at an applied voltage of 5V. In fatigue characteristics value remained costant up to$8{\times}10^{10}$ read/write switching cycles at a frequency of 1Mhz regardless of annealing temperatures. -
The microwave dielectric properties and the microstructures on
$Bi_{0.97}Nb_{0.03}O_{4}$ doped with$V_{2}O_{5}$ were systematically investigated.$Bi_{0.97}Tm_{0.03}Nb_{0.03}O_{4}$ ceramics sintered at$920-960^{\circ}C$ were mainly consisted of orthorhombic and triclinic phases after addition of$V_{2}O_{5}$ . The apparent density increased slightly with increasing the$V_{2}O_{5}$ addition. The dielectric$constants(\varepsilon_r)$ also increased with$V_{2}O_{5}$ addition(30-45). The$Q{\times}f_0$ values measured on$Bi_{0.97}Tm_{0.03}NbO_4$ ceramics doped with$V_{2}O_{5}$ were between 2,000 and 12,000[GHz] when the sintering temperatures are in the range of$920-960[^{\circ}C]$ . It was confirmed the temperature coefficient of the resonant$frequency(\tau_f)$ can be adjusted from a positive value of$+10[ppm/^{\circ}C]$ to a negative value of$-15ppm/^{\circ}C$ by increasing the amount of$V_{2}O_{5}$ . Based on our experimental results, the Bi0.97Tm0.03NbO4(added V2O5) ceramics can be applied to multilayer microwave devices at low sintering temperatures. -
박막과 후막을 구분하고 현재에는 막의 형성 구분에 따라 박막에는 진공증착 후막에는 Screen Printing, Dipping, Brashing, Rolling으로 구분한다. 기술에는 여러 가져가 있는데, 금속 분말 제조기술, 유리분말제조기술, 유기바인더제조기술, 첨가제배합기술, 전자측정기술, 분체제어기술이 있다. 본 연구의 목표는 용도에 알맞은 최적화된 새로운 제조기술을 제시하고자 한다.
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체적파 박막형 공진기 (FBAR: Film Bulk Acoustic wave Resonator)소자를 제조하여, 박막의 c축 우선 배향성을 조절하는 것이 FBAR 소자 특성을 확인하였다. 본 연구에서는 MEMS 공정에 의해 Membrane 구조의 FBAR(Film Bulk Acoustic wave Resonator) 소자를 구현하고자 하였다. 이를 위해 Si 기판을 Back-etching 하여 membrane 구조를 제작하였고 압전층으로 ZnO을 Sputtering 공정에 의해 증착 후, 공정 조건에 따른 우선 배향성을 관찰하였다.
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This paper, experiment manufactures device of Metal/Poly-
${\gamma}$ Benzyl$_D$ -GlutamateOrganic Films/Metal structure using PBDG and I-V properties and C-F properties. The I-V characteristic is measured that approve voltage from 0 to +2[V] of device and the distance between electrode is larger, could know that small current flow and thin film could know that had insulation property. C-F characteristic has each other affinity between the polarization amount and frequency. Permittivity of MIM device could know by dipole that is voluntary polarization of LB film that polarization is happened. The capacitor properties of a thin film is better as the distance between electrodes is smaller. -
At present, the study of direct digital X-ray detector and indirect digital X-ray detector proceed actively. But it needs high thickness and high voltage in selenium for high ionization rate. Therefore, we carried out the study of electric characteristics of a-Se with additive ratio of Iodine in drafting study for developing Hybrid X -ray Sensor for complementing direct digital X -ray detector and indirect digital X-ray detector in this paper. On this, there are formed Amorphous selenium multi-layers by sticking phosphor layer
$(Gd_{2}O_{2}S(Eu^{2+}))$ using optical adhesives of EFIRON Co. Amorphous selenium multi-layers having dielectric layer(parylene) has characteristics of low dark-current, high X-ray sensitivity. So we can acquired a enhanced signal to noise ratio. We make Amorphous selenium multi-layers with$30{\mu}m$ thickness on glass. -
Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposistion because In and Sb has been very different feature of vapor pressure (
$10^{-4}$ times) When In and Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering and we study properties of magneto-resistance by annealing. -
There has recently been a great deal of interest in amorphous selenium for application of digital x-ray image sensor. The initial number of the electron-hole induced by interaction a-Se with x-ray photons and the collection efficiency to surface of generated charges are important parameters for x-ray sensitivity of the a-Se. Therefore, in this paper, we analyzed that thickness of a-Se film and electric field is affected on the initial number of electron-hole and the collection efficiency. The experimental value of x-ray induced charge about the various thickness and the electric field is compared with estimated absorbed energy through MCNP 4C code to analyze the mechanism x-ray induced signal of a-Se. The experimental results showed that the electric field depends on initial escape coefficient and the thickness depends on collection coefficient than escape efficient.
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Lately, intensifying screen of the
$CaWO_4$ is used to medical treatment and diagnosis of the image. In this paper, we investigated transmission fraction and mass attenuation coefficient of$CaWO_4$ screen about diagnostic x-ray of low energy using MCNP 4C code. Experimentally, for 0.9 mm-$CaWO_4$ screen, the absorbable rate of diagnostic x-ray is more than 95%. according to kVp, the experimental value of mass attenuation coefficient is in a1most agreement with an corrected estimate value of MCNP and the deviation of experimental values is less than${\pm}7%$ . Using the MCNP code through this paper, we can make an estimate of signal and design for construction of the CaWO4/a-Se based digital x-ray image detector and make a good use of the foundation data for development of other materials. -
This paper reports on the fluid flow simulation results of an active microvalve. The mechanical and fluidic analysis are done by finite element method. The designed structure is normally closed microvalve using buckling effect, which is consist of three separate structures; a valve seat die, an actuator die and a small piezoelectric actuator. It is confirmed that the complete laminar flow and the lowest flow leakage are strongly depend on the valve seat geometry. In addition, turbulent flow was occurs in valve outlet according to increase seat dimension, height and inlet pressure. From this, we was deducts the optimum geometry of the valve seat and diaphragm deflection that have an great influence fluid flow in microvalve. Thus, it is expected that our simulation results would be apply for constructing integrated chemical analyzing system or drug delivery system.
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SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS(micro electro mechanical system) fields because of its application possibility in harsh environments. This paper presents pre-bonding techniques with variation of HF pre-treatment conditions for 2 inch SiC wafer direct bonding using PECVD(plasma enhanced chemical vapor deposition) oxide. The PECVD oxide was characterized by XPS(X-ray photoelectron spectrometer) and AFM(atomic force microscopy). The characteristics of the bonded sample were measured under different bonding conditions of HF concentration and an applied pressure. The bonding strength was evaluated by the tensile strength method. The bonded interface was analyzed by using IR camera and SEM(scanning electron microscope). Components existed in the interlayer were analyzed by using FT-IR(fourier transform infrared spectroscopy). The bonding strength was varied with HF pre-treatment conditions before the pre-bonding in the range of
$5.3 kgf/cm^2$ to$15.5 kgf/cm^2$ -
There has recently been much interest and research in developing digital x-ray systems based on using amorphous selenium(a-Se) photoconductors as the image receptor. The amorphous selenium layer that is currently being studied for use as an x-ray photoconductor is not pure a-Se but rather amorphous selenium alloyed with arsenic. We fabricated samples using the selenium and arsenic alloy with various concentrations of the arsenic. In this work, x-ray photoconductor using amorphous selenium alloyed with arsenic were fabricated with different concentrations of the arsenic (0.1 wt.%, 0.3wt.%, 0.5wt.%, 1wt.%, 1.5wt.%, 3wt.%, 5wt.%). The seven kind of samples was fabricated with a-Se alloyed with arsenic through vacuum thermal evaporation. We also investigate the arsenic concentration dependence on the device performance in radiation detector. The electric characteristics of radiation detector devices with changing additive ratio of the arsenic is performed by measuring the x-ray induced photocurrent and integrating it over time to find the total charge. The thickness of a-Se is
$100{\mu}m$ . Bias voltages$3V/{\mu}m$ ,$6V/{\mu}m$ ,$9V/{\mu}m$ are applied at the samples. As results, the net charge of a-Se 0.3% As sample is$526.0pC/mR/cm^2$ at$9V/{\mu}m$ bias. The net charge is decreased as with the increasing additive ratio of arsenic. -
Many research group started study to develope x-ray detector using thin film transistor from 1970. But realization of TFT based x-ray detector development was caused by progress of thin film transistor liquid crystal display(TFTLCD) device technology in 1990. The main current of TFT technology is display device. Research results expend TFT technology field from display device to sensor manufacture technology. These days many research group in the world realize various digital x-ray detector. In this study, We compare discharge erasing method to visible light erasing method in a-Se based digital x-ray detector. Visible light erasing method is known reset process in direct conversion x-ray detector. Digital x-ray detector using visible light erasing method is not adaptive for conventional x-ray device, because of its thickness. And it is not avaliable for real-time imaging for digital fluoroscopy, because of its long reset time. In this study we overcome these limitations and show new idea for real-time imaging method.
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This paper is researched that electric characteristic of Digital x-ray radiography technique with changing composition ratio of Iodine. Dopant material, Iodine is evaporated with amorphous selenium. Thorugh the old papers say, doponted Iodine will be down the created trap level because of Arsenic dopant material in amorphous selenium. Arsenic material of Composition ratio in amorphous selenium is fixed with 0.3% and test sample is deposited composition of 30, 100, 300, 500, 700ppm with thermal evaporate system. Experimental measurement is performed by dark current and x-ray sensitivity in amorphous selenium based radition detector sensor. Fabricated test sample thickness is
$30{\mu}m$ and injected voltage is$3{\mu}m$ ,$6{\mu}m$ ,$9{\mu}m$ to both electrode. Experimental results showed that the net charge of composition rate of 30ppm is 398.88 pc/mR/$cm^2$ very high. And increase of the Iodine composition ratio is tendency to the decrease of net charge. Doping changing composition of Iodine in amorphous selenium detector offered to basical information of amorphous selenium material. -
Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electroeds as well as micellar assemblies. which can be profitably utilized for display devices. photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator[1-3]. Fromherz et al studied the se1f-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface[4]. In this study, the electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency
$({\Delta}F)$ and resonant resistance(R). The redox process of viologen was observed with resonant frequency$({\Delta}F)$ . -
Thermal oxidations of 3C-SiC thin-films grown on Si(100) by APCVD(atmospheric pressure chemical vapor deposition) were carried out. The oxidations of 3C-SiC were performed at
$1100^{\circ}C$ for 1~6 hr in wet and dry$O_2$ ambient, respectively. Ellipsometry was used to determine the thickness and index of refraction of oxide films. The oxide thickness vs. the oxidation time follows the general relationship used for the thermal oxidation of Si. The surface roughness was analyzed by using AFM(atomic force microscopy). The surface roughness of oxidized 3C-SiC was rougher than before oxidation. The thermal oxide was found to be$SiO_2$ by XPS(X-ray photoelectron spectroscopy) analysis. Auger analysis showed them to be homogeneous with near stoichiometric composition. -
Precision resistors were prepared by controlling the concentration of Ni and Cr deposited on cylindrical alumina substrates (diameter: 1.7mm, length: 5.5mm). Deposited films were analyzed with FESEM, AES, and AFM. As the amount of Cr in the film increases, the TCR was shifted to negative direction.
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There are being two prominent studying for Digital Radiography. Direct and Indirect method of Digital Radiography are announced for producing high quality digital image. The one is using amorphous selenium as photoconductor and the other is using phosphor layer as a light conversion. But each two systems have strength and weakness such as high voltage and blurring effect. In this study, we investigated the electrical characteristic of
$multi-layer\left(CaWO_{4}+a-Se \right)$ as a photoconductor according to the changing arsenic composition ratio. This is a basic research for developing of Hybrid digital radiography which is a new type X-ray detector. The arsenic composition ratio of a-Se compound is classified into 7 different kinds which have 0.1%, 0.3%, 0.5%, 1%, 1.5%, 5%, 10% and were made test sample throught thermo-evaporation. The phosphor layer of$CaWO_4$ was overlapped on a-Se using EFIRON optical adhesives. We measured the dark and photo current about the test sample and compared the electrical characteristic of the net charge and signal-to-noise ratio. Among other things, test sample of compound material of 0.3% arsenic showed good characteristic of$2.45nA/cm^2$ dark current and$357.19pC/cm^2/mR$ net charge at$3V/{\mu}m$ . -
In recent years, there has been keen interest in developing f1at panel detectors for all modalities of radiology, including gerneral radiology, fluoroscopy(angiography and cardiology), electronic portal imaging, and mammography. In this paper, we report the new hybrid x-ray detector consisted of CsI(Tl) photoemission layer and a-Se photoconductor layer to resolve conventional x-ray detector such as the direct detector using a-Se and the indirect detector using CsI(Tl)/a-Si. To design the structure of CsI(Tl)/a-Se detector, the penetrated energy spectrum and absorption fraction was estimated using MCNP 4C code. Experimental results showed that the absorption fraction of
$500{\mu}m-Se$ film and$150{\mu}m-CsI\left(Tl \right)/a-Se\left( 30{\mu}m \right)$ film is 70% at 70 kVp. The absorption energy is 90% at$350{\mu}m-CsI(Tl)$ . -
In this papaer, there is a basic research for the development of the Hybrid digital radiation detector with a new system, make up for existing digital radiation detector of direct/indirect method with a weak point. for enhance the efficiency characteristics of signal response from X-ray detector using the a-Se, We make sample with various kinds of layer, through the ratio of As(0.l%,0.3%,0.5%,1%,1.5%,5%,10%). We measure net charge with a leakage current and photo current for electric charateristics. Ratio of As in a-Se consist of 7 stage, It made of using the thermal deposition system, In the made of samples, we made multi layer using the EFIRON optical adhesives from phosphor layer consist of Oxybromide
$(BrO_2)$ . As a result of X-ray measurement, the best result is ; leakage current(0.30nA/cm2), net charge(610.13pC/cm2/mR) when the condition is voltage(9V/um), 0.3% ratio of As in multi layer(BrO2 + a-Se) -
Recently, the study on development of electrical and electronic device is done to get miniature, high degrees of integration and efficiency by using inorganic materials. the study of Langmuir-Boldgett(LB) method that uses organic materials because of the limitation for the ultrasmall size. The structure of MIM(Metal-Insulator-Metal) device is Cr-Au/ PBLG/ Al. the number of accumulated layers are 1, 3, 5, 7, 9. The I-V characteristic of the device is measured from 0[V] to 2[V] and the characteristic of current-time of the devices. We have investigated the capacitance because PBLG system have a accumulated layers the maximum value of measured current is increased as the number of accumulated layers are decreased. The capacitor properties of a thin film is better as the distance between electrodes is smaller. The results have shown the insulating materials and could control the conductivity by accumulated layers.
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Choe, Jang-Yong;Lee, Dong-Gil;Sin, Jeong-Uk;Kim, Jae-Hyeong;Nam, Sang-Hee;Park, Ji-Koon;Kang, Sang-Sik;Jang, Gi-Won;Lee, Hung-Won 432
The ultimate study of this research is to improve the properties of digital X-ray receptor based on amorphous selenium. There are being two prominent studying for Digital Radiography. Direct and Indirect method of Digital Radiography are announced for producing high quality digital image. But each two systems have strength and weakness. This is a basic research for developing of Hybrid digital radiography which is a new type X-ray detector. ln this study, we investigated the electrical characteristic of multi-layer$(CaWO_4+a-Se)$ as a photoconductor according to the changing iodine composition ratio. The iodine composition ratio of a-Se compound is classified into 5 different kinds which have 30ppm, 100ppm, 300ppm, 500ppm, 700ppm and were made test sample throught thermo-evaporation. The phosphor layer of$CaWO_4$ was overlapped on a-Se using EFIRON optical adhesives. We measured the dark and photo current about the test sample and compared the electrical characteristic of the net charge and signal-to-noise ratio. Among other things, test sample of compound material of 700ppm iodine showed good characteristic of$2.53nA/cm^2$ dark current and$479nC/cm^2{\cdot}mR$ net charge at$3V/{\mu}m$ . -
Recently, It has performed that the basic research of the photoconductive material and the development and application of the digital radiograph detector which is divided into the direct and indirect method. The objective of this study investigate the effect of the electric characteristic about changing the composition of Arsenic in hybrid detector system for compensating a defect of conventional. We fabricated samples using the amorphous Selenium and Arsenic alloy with various concentrations of the Arsenic{seven step 0.1%, 0.3%, 0.5%, 1%, 1.5%, 3%, 5%). And using EFIRON optical adhesives the formed multi-layer
$(Gd_{2}O_{2}S(Eu^{2+}))$ composed phosphor layer. X-ray and light sensitivity was measured to study x-ray response characteritics. As results, highest value was measured as output net charge and SNR were$315.7pC/cm^2/mR$ and 99.4 at 0.3%As doping ratio. -
Present1y the X-Ray diagnosis system is a real condition that is changing by digital ways in it's existent analog ways. This digital radiation detector is divided by the direct method and the indirect method. The indirect method of applied voltage has special qualities that the resolution is low than direct method by diffusion effect that happens. The conversion process ( radiation
${\rightarrow}$ visible ray${\rightarrow}$ electrical signal of two times, has shortcomings that the energy conversion efficiency of electrical signal is low. The direct method has shortcomings that need strong electric fie1d to detect electrical signal efficiently. This research achieved to develop digital detector of the Hybrid method that have form that mixes two ways to supplement shortcoming of direct. indirect method. A studied electrical characteristic by Iodine's Mixture ratio change is added to selenium in the detector which has a multi-layer structure (Oxybromide + a-Se). There are 8 kinds of Manufactured compositions to amorphous selenium Iodine each 30ppm, 100ppm, 200 ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm by a doped photoconductor through a vacuum thermal evaporation method. The phosphor layer is consisted of Oxybromide ($BrO_2$ ) which uses optical adhesives multi-layer structure. The manufactured compositions calculates and compares Net Charge and signal to noise ratio measuring Photocurrent about Darkcurrent and X-ray. When doped Iodine Mixture ratio is 500ppm to the multi-layer structure (Oxybromide + a-Se), applied voltage of$3V/{\mu}m$ , leakage current of compositions$2.61nA/cm^2$ and net charge value by 764pC/$cm^2$ /mR then the best result appeared. -
The Jig cells are fabricated in the drying room, and consisted of elemental sulfur used as a cathode active material, lithium metal used as a anode material and 1M
$LiCF_{3}SO_{3}$ dissolved in TG (Tetraglyme)/DIOX (1,3-Dioxolane) used as a electrolyte. The four kinds of electrolytes with different content of TG and DIOX are prepared. The electrochemical properties of the foregoing electrolytes-based lithium sulfur batteries are analyzed by AC impedance experiments. The conductivity of four different electrolytes is investigated. The conductivity of electrolyte [1M$LiCF_3SO_3$ dissolved in TG/DIOX (50:50, vol.)] is higher than that of other three kinds of electrolytes with different volume ratio (70:30, 30:70) and single solvent (TG). -
The possibility of using polypyrrole as a drug delivery system(DDS) has been studied using indicate (Phenol red) and substance with therapeutic activity(Sodium salicylate). In aqueous solution, negative potential is applied to polypyrrole then anion(with therapeutic activity) of sodium salicylate is released by redox processes of polypyrrole. The release amount of anionic drugs from polypyrrole is measured by UV-visible spectrometer which can measure UV-absorbance of materials. Electrode area that use for release amount measurement is
$50mm^{2}(5{\times}10mm)$ ,and thickness of polypyrrole membrane is$15{\mu}m$ . DC 1V applied in saline solution, the release amount according to time increased gradually. In various electrode area, release amount of anionic drug is directly to electrode area. -
Single crystal 3C-SiC(cubic silicon carbide) thin-films were deposited on Si(100) substrate up to a thickness of
$4.3{\mu}m$ by APCVD method using HMDS(hexamethyildisilane) at$1350^{\circ}C$ . The HMDS flow rate was 0.5 sccm and the carrier gas flow rate was 2.5 slm. The HMDS flow rate was important to get a mirror-like crystal surface. The growth rate of the 3C-SiC films was$4.3{\mu}m/hr$ . The 3C-SiC epitaxical films grown on Si(100) were characterized by XRD, AFM, RHEED, XPS and raman scattering, respectively. The 3C-SiC distinct phonons of TO(transverse optical) near$796cm^{-1}$ and LO(longitudinal optical) near$974{\pm}1cm^{-1}$ were recorded by raman scattering measurement. The heteroepitaxially grown films were identified as the single crystal 3C-SiC phase by XRD spectra$(2{\theta}=41.5^{\circ})$ . -
This paper describes fabrication and characteristics of ceramic pressure sensor for working at high temperature. The proposed pressure sensor consists of a Ta-N thin-film, patterned on a Wheatstone bridge configuration, sputter deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097~1.21mV/
$V{\cdot}kgf/cm^2$ in the temperature range of$25{\sim}200^{\circ}C$ and the maximum non-linearity is 0.43 %FS. -
$MoO_3$ thin films were deposited on electrode and heater screen-printed alumina substrates in$O_2$ atmosphere by RF reactive sputtering using Molybdenum metal target. The deposition was performed at$300^{\circ}C$ with 350W of a forward power in an$Ar-O_2$ atmosphere. The working pressure was maintained at$3{\times}10^{-2}mtorr$ and all deposited films were annealed at$500^{\circ}C$ for 5hours. To investigate gas sensing characteristics of the addition doped$MoO_3$ thin film, Co, Ni and Pt were used as adding dopants. The sensing properties were investigated in tenn of gas concentration under exposure of reducing gases such as$H_2$ ,$NH_3$ and CO at optimum working temperature. Co-doped$MoO_3$ thin film shows the maximum 46.8% of sensitivity in$NH_3$ and Ni-doped$MoO_3$ thin film exhibits 49.7% of sensitivity in$H_2$ . -
$TiO_{2}-Co_{3}O_{4}$ humidity sensors were fabricated by conventional ceramic process and their humid sensing characteristics were investigated. The sample which was added 10wt%$Co_{3}O_{4}$ and heat-treated$1200^{\circ}C$ showed the highest sensitivity to humidity changes and improved a linearity. As$Co_{3}O_{4}$ content was increasing, the sensor consists a uniform pore distribution and grain in the surface. This was analyzed by SEM photographs. -
A strong need to improve the quality of electric power is increased because of increasing use of the sensitive and small-sized electronic devices. The surges on the low-voltage ac power lines are induced by nearby lightning return strokes, and the facilities for HA, OA, FA, ME as well as computer are easily damaged by high-voltage transients. The behaviors of lightning surge characteristics transferred from the primary winding to the secondary winding in distribution transformers using a Marx generator were experimentally investigated. The transfer characteristics of lightning surge associated with a custom service ground of secondary side were also examined.
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A Rogowski coil can measure alternating currents from a few amps to over 1 million amps in a frequency range from less than 0.1 Hz to about lMhz. A Rogowski coil provides an induced output voltage which is proportional to the rate of change of the primary current enclosed by the flexible or the rigid coil-loop. Therefore, it is necessary to integrate the output voltage in order to produce a voltage proportional to the current. Also. it can reproduce the current waveform on an oscilloscope or any type of data acquisition device. This paper describes the practical design of the combination of a Rogowski coil and an integrator which provides a versatile current measuring system to accommodate a wide range of frequencies, current levels and conductor sizes.
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The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied the effect of cement displacement resulting environmental ageing parameters on porcelain insulator mechanical properties for transmission line by simulation (ANSYS/NASTRAN program) and test methods. These simulation analysis and experimental results show that cement volume growth affects severely to be mechanical failure ageing.
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This paper through shift norm of insulator and research by accident prevention countermeasure special skill authoritativeness verification of insulator and Long Term aging factor for power transmission analysis and evaluate and prove quality of insulator wish to. Assessment technique by aging of own porcelain insulator observes ageing factor for reciprocity comparison through several examinations. Through cool and heat accelerated Aging test, can measure the leakage current change amount that ensue to each Cycle. Can confirm own blazing fire factor as distribution freshness that ensue in HRB Test's hardness value.
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The mold transformers have been widely used in underground substations in large building and have some advantages in comparison to oil-transformer, that is low fire risk, excellent environmental compatibility, compact size and high reliability. In addition, the application of mold transformer for outdoor is possible due to development of epoxy resin. The mold transformer generally has cooling duct between low voltage coil and high voltage coil. A mold transformer made by one body molding method has been developed for small size and low loss. In this paper, the proto type mold transformer of 50kVA class is investigated by routine, type, special test. The outdoor energized aging test is investigated by back-to-back method to verify the long time performance of pole mold transformer. The aging process of transformer is analyzed by various diagnosis method such as DC voltage-current test,
$tan{\delta}$ , Meggar measurement, winding temperature and etc. -
We report the observation of line shapes in the optogalvanic spectrum, which are different from those of absorption, for transitions origination from the
$3P_2$ ($1s_5$ in Paschen notation) metastable level of argon. The OG line shapes resemble those of absorption and be used to diagnose the characteristics of the discharge plasma. The measured plasma temperatures of Ar hollow cathode discharge for several metal cathodes are about 620~780K at discharge current of 7~10mA. -
The fundamental principles of the operation of microwave discharges that are used to convert microwave energy to broad spectrum visual light are known. In this paper, emission dependance of microwave discharges in mixture content of sulfur with noble gases was studied. It is shown that the excitation of this gaseous mixture is carried out in two phases: (1) ionization of noble gas atoms by a microwave field and (2) the consequent maintenance of slightly ionized nonequilibrium plasma by the field. These two processes have essentially various thresholds for the microwave pump. The purpose of this work is to investigate spectral properties of the high frequency discharges in a mixture sulfur vapors with noble gases.
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This paper describes the results the problem of stress calculation and optimization into a FRP(Fiber-glass Reinforced Plastic) tube crimped into a metal end-fitting. This type of assembly is used mainly is used mainly for suspension and line post insulators. Fitting strength of FRP and flange of this study is required greatly from composite insulator to important special quality. Therefore, wish to seek analysis and mechanical strength performance that follow to FRP tube and flange of top and bottom mechanical fitting.
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본 연구에서는 ETL층으로 널리 알려져 있는 PBD(2-(4-biphenyl)-5-(4-tert-butylphenyl) -1.3,4oxadiazole)를 HBL(Hole-blocking layer) 물질로 이용 하고 Nile red를 사용하여 적색 발광의 EL(electroluminescence) 소자를 제작 평가하였다. 일반적인 유기 EL 소자의 구조인 Anode/HTL(Hole Transport Layer)/ETL(Electron Transport Layer)/Cathode로 이루어져 있다. 여기에 HTL과 ETL사이에 HBL를 추가하여 EL 소자의 성능을 향상 시킬 수 있으면, 이러한 구조의 최종 소자를 제작 EML(emitting layer; Nile red)의 두께 및 임계전압을 달리 하여 소자 의 특성을 평가 연구 하였다.
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본 논문에서는 냉음극 형광램프의 구조 및 동작원리를 파악하고 램프의 특성을 알아본다. 램프의 특성에 영향을 주는 요소인 관경, 관길이, 가스압, 전극등을 최적화 하여야 하고 CCFL(cold cathode fluorescent lamp) 의 휘도가 관선류, 주파수, 가스압력, 주위온도에 의한 영향에 따른 전기적 및 광학적인 특성을 분석하고자 한다.
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In this paper. we give pressure stimulation into organic ultra thin films and detected the induced displacement current proper ties, and then manufacture a device under the accumulation condition. In processing of a device manufacture. And electroluminescence(EL) from conjugated polymers has recently received great attention because polymer light-emitting diodes(LEDs) clealy have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the elextrodes. followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material. In this paper, we fabricated the single layer EL device using
$Alq_3$ as emitting material. According as turn on voltage could know about 5.5V in voltage-current characteristics and voltage rise, current could see that increase as non-linear, Current and ruminance can see that express similar relativity in voltage, and could know that ruminance is expressing current relativity. -
Ryu, Seong-Ryong;Lee, Tae-Dong;Kim, Yong-Gil;Byun, Chang-Woo;Park, J.W.;Ko, S.W.;Chun, H.T.;Ko, N.J. 510
띠모양의 에미터와 에미터와 정렬된 띠모양의 케이트 구멍을 가진 탄소나노튜브(CNT) 삼극 구조에 대하여 전계방출 시뮬레이션을 수행하였다. 전자방출은 주로 가장자리에서 발생하였으며 에미터와 게이트사이의 간격이 가까워지면 급격히 증가하였다. 전자방출 특성도 상당히 우수하였다. 한쪽 가장자리만을 사용한 삼극구조의 경우에는 방출된 전자의 궤적이 좁은 띠모양으로 형성되어 방향성이 매우 우수하게 나타났다. 띠모양의 에미터 및 게이트로 이어진 삼극구조는 제작이 용이하고 조립할 때 정렬이 쉬운 장점이 있다. -
We investigated response characteristics of twisted nematic (TN) cell with different nematic liquid crystals (NLCs) and cell gap d on a rubbed polyimide (PI) surface. High transmittance and fast response time of the TN cell on the rubbed PI surface were achieved by using high birefringence (
${\Delta}n$ ) and low cell gap d. The response time of TN cell on the rubbed PI surface was measured 5.1 ms. The transmittance and response time of the TN cell on the rubbed PI surface decreased with decreasing${\Delta}nd$ . -
New luminescent material, 6,11-Dihydroxy-5,12-naphthacenedione
$(Alq_2-Ncd)$ was synthesized. And extended efforts have been made to obtain high-performance electro-luminescent(EL) devices, since the first report of organic light-emitting diodes(OLEDs) based on tris-(8-hydroxy-quinoline)aluminum$(Alq_3)$ Current-voltage characteristics, brightness-voltage characteristics, luminous efficiency and quantum efficiency were measured at room temperature. The maximum wavelength of the EL is at around 504nm and the brightness is up to$2702[cd/m^2]$ with the maximum efficiency up to 3.91 [1m/W]. This study indicates not only the sterical effect but also some other effect would be responsible for the change of the emission wavelength. -
본 논문에서는 고휘도 LCD 백라이트 유닛에 사용되는 직하방식 백라이트 제조 방법을 이용하여 저전력, 고휘도, 경박 단소의 광고용 사인보드를 설계 제작하였다. 광학 시뮬레이션을 이용하여 램프의 배치 등 을 설계하였으며. 최고 16개의 냉음극관 램프를 구동할 수 있는 인버터를 설계 제작하였다. 크기
$500mm{\times}400mm$ 의 광고판의 경우 두께는 35mm 이었으며 휘도는 15,000lux이었다. -
We studied the nematic liquid crystal (NLC) aligning capabilities by the UV alignment method on a diamond like carbon (DLC) thin film surface. A good LC alignment by UV exposure on the DLC thin film surface at
$200\AA$ of layer thickness was achieved. Also, a good LC alignment by the UV alignment method on the DLC thin film surface was observed at annealing temperature of$180^{\circ}C$ . However, the alignment defect of the NLC was observed above annealing temperature of$200^{\circ}C$ . Consequently, the good thermal stability of LC alignment by the UV alignment method on the DLC thin film surface can be achieved. -
EO Characteristics in the Advanced Vertical Alignment VA-
$\pi$ Cell on a Homeotropic Blended PolymerBlending effects for generating a pretilt angle in nematic liquid crystal (NLC) with negative dielectric anisotropy on the blended polyimide (PI) of homeotropic and homogeneous alignment surface were studied. Also, we investigated the EO performances for the advanced VA-$\pi$ cell using this homeotropic blended PI surface. A many decrease of tilt angle on the polymer surface to blend homeotropic PI and homogeneous PI with side chain type was measured, and the tilt angle decreased as blended ratio and rubbing strength increase. The blended effects for generating a pretilt angle were clearly observed, and the many decrease of tilt angle can be achieved by using the blended PI surface. The electro-optical (EO) characteristics using the advanced VA-$\pi$ cell using the homeotropic blended PI surface than that of conventional VA cell can be improved. We suggest that the developed advanced VA-$\pi$ cell on a homeotropic blended PI surface is a promising technique for the achievement of a fast response time, and a high contrast ratio. -
We have studied conduction mechanism that is interpreted in terms of space charge limited current (SCLC) region and tunneling region. The OLEDs are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris (8- hydroxyquinolinoline) aluminum(III)
$(Alq_3)$ as an electron injection and transport and emitting later, copper phthalocyanine (CuPc) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and poly(vinylcarbazole) (PVK) as a buffer layer respectively. Al was used as cathode. We manufactured reference structure that has in ITO/TPD/$Alq_3$ /Al. Buffer layer effects were compared to reference structure. And we have analyzed out luminance efficiency-voltage characteristics in ITO/Buffer layer/TPD/$Alq_3$ /Al with buffer-layer materials. -
Lee, Tae-Dong;Ryu, Seong-Ryong;Byun, Chang-Woo;Kim, Young-Kil;Ko, N.J.;Chun, H.T.;Park, J.W.;Ko, S.W. 538
탄소나노튜브 (CNT)가 도포된 평면형 에미터와 원형 개구의 게이트 전극을 가지는 삼전극 전계방출 소자의 전계방출 특성을 시뮬레이션하였다. 체계적인 시뮬레이션을 위해 소자 내 전위의 공간적 분포 특정을 결정하는 전계형상인자$\gamma$ 를 정의하고 이 값에 따른 전위분포의 특성과 방출 전자의 궤적을 계산하였다. 계산 결과$\gamma$ > 1 인 전압조건에서는 에미터의 가운데를 중심으로 강한 전자방출이 발생하고 전자빔이 구조의 축 방향으로 자체 집속됨을 알 수 있었다. 이렇게 되면 에미터와 게이트의 정렬이 전혀 필요하지 않게 되며 또한 별도의 전자집속회로 없이도 에미터와 양극에 있는 형광체가 1:1 로 대응하는 획기적인 디스플레이 구조를 가능하게 해 준다 적정 전압조건에서 CNT의 전계강화인자$\beta$ 의 변화에 따른 총 전류를 계산한 결과,$\beta$ >3000인 CNT를 사용할 경우 실제 소자로서 구현이 가능함을 확인하였다. -
High performance organic electroluminescnet(EL) devices which are composed of organic thin multilayer films are fabricated. The basic structure is ITO/Emitting layer/LiF/Al in which have a blended emitting layer. The emitting layer is consisted of a host material(N,N' diphenyl-N,N' (3-methyl phenyl)-l,l'-biphenyl-4,4'diamine)(TPD)) and a guest emitting material(poly(3-hexylthiophehe)(P3HT)). We think that the energy transfer in blending layer occurred from TPD to P3HT. Red emitting multilayer EL devices were fabricated using tris(8-hydroxyqunolinate) aluminum
$(Alq_3)$ as electron transport material. The device structure of ITO/blending layer(TPD+P3HT)$/Alq_3$ /LiF/Al was employed. In the Voltage-current-luminance characteristics of multilayer device, the device tum on at the 2V and the luminance of$10{\mu}W/cm^2$ obtain at l0V. Red emission peak at 640nm was observed with this device structure. We have presented evidence that the excitation energy migration between a polymeric host and guest has to be explained. And by using multilayer, the red light emitting EL device enhances not only Voltage-current-luminance characteristic but also stability of device. -
Ni thin film on the PMN-PT crystal wafer were deposited by using E-beam evaporator technique. Deposited film was patterned by UV-lithography and etching and was in-diffused at 300~600C. Diffusion profile of Ni ions in PMN-PT was measured by secondary ion mass spectroscopy (SIMS).
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본 장치는 다층막 스퍼터링 증착장치로써 박막을 증착시키는데 용이하게 설계하는 것이 목적이며, 박막두께가 균일하게 증착되고 진공조 내부의 압력을 일정하게 제어가 가능하고 배기시스템은 스퍼터실과 증착실의 진공배기를 공용으로 구조를 설계하여 장치의 스퍼터링 증착조건에 적합하도록 연구실험용으로 설계되어졌다.
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The microstructure and electrical characteristics of A~C's ZnO varistors fabricated according to variable sintering condition, which sintering temperature is
$1130^{\circ}C$ and speeds of pusher are A: 2mm/min, B: 4mm/min, C: 6mm/min, respectively, were investigated. In the microstructure, A~C's ZnO varist-ors fabricated variable sintering condition was consisted of ZnO grain(ZnO), spinel phase$(Zn_{2.33}Sb_{0.67}O_4)$ Bi-rich$phase(Bi_{2}O_{3})$ , wholly. Varistor voltage of A~C's ZnO varistors sintered at$1130^{\circ}C$ increased in order A < B < C's ZnO varistors. C's ZnO varistor exhibited good characteristics that nonlinear exponent is 31.70. Leakage current of A~C's ZnO varistors exhibited below 2mA at rated voltage. Lightning impulse residual voltage of A's ZnO varistor suited standard characteristics, which is 3.85kV at 2.5kA, 4.4kV at 5kA and 5.16kV at 10kA. After multi lightning impulse residual voltage test of A's ZnO varistor exhibited good discharge characteristics which ZnO varistor reveals no evidence of puncture, flashover, cracking in visual examination. After high current impulse test of A's ZnO varistor exhibited good discharge characteristics, which variation rate of residual voltage is 0.4% before and after test, and revealed no evidence. -
본 논문에서는 전자식 형광등의 직류구동과 AM 변조시 빛의 주파수 특성에 관하여 다루고 있다. 전자식 형광등을 구동하는 안정기 회로는 상용전원을 직류로 정류시켜 고주파로 변환하여 형광등을 구동시킨다. 형광동의 구동에 사용되는 안정기 회로의 내부 평활 컨덴서의 유.무와 각각 공급되는 전원을 상용전원인 경우, 상용전원을 정류한 경우, 상용전원을 정류하고 정현파를 AM 변조한 경우에 대해서 측정하였으며, 변조하여 입력되어진 정현파가 빛을 통해서 송신되는 것을 확인할 수가 있었다.
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In recent years, environments of our globe has been getting worse as a result of rapid growth of socioeconomic activities. The global environmental issues of acid rain, green house effect and ozone depletion are caused by various chemical pollutants, emitted from industries, automobiles and home. Most of these pollutants are produced by combustion processes. CO2 as a chief criminal of the greenhouse effect is a main combustion product of fossil fuels. Development of solid-state electrochemical devices for detecting CO2 is demonstrated based on various combination of solid electrolytes and auxiliary sensing materials. The object of this research is to develop various sensor performance for solid electrolyte gas sensor, and to test gas sensor performance manufactured. So we try to present a guidance for developing potential type gas sensor. We concentrated on development of manufacturing process and performance test.
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The value of charge current, discharge current,
$\varepsilon_r$ '$\varepsilon_r"$ , residual voltage was measured inorder to investigate electric properties in Ethylene Prophylene Rubber for is irradiated$CO^{60}\gamma$ ray 0-38.1 Mrad. The value of charge current and the discharging current of the EPR is influenced by$CO^{60}-{\gamma}$ -irradiation dose The charging current and the discharging current of EPR increase, depending on the ratio of degradation. As the irradiation dose is increased, the peak of residual voltage moves to the slorter time. The properties specific electric constant due to time variation was appeared dispersion by plentiful$CO^{60}-{\gamma}$ -irradiation dose. The increase of peak in$\varepsilon_r"$ is attrib uted to the irratiation dose almost proportionally. -
The reduction method of harmonic currents is very important, when harmonic influences of the systems connections of AC power lines with dispersed generations like solar energy and wind power generation etc, increase more and more. Which the influences of harmonic currents bring not only the drop of power quality but also many trouble occurrences of various systems. Recently, the necessity about application development of new substitute energy has gone up, and the development and practical use of dispersed power lines are proceeding now. Henceforth, a counterplan against harmonic influences must be devised for more practical use of new substitute energy. In this paper, we studied the harmonic influences and new devices for that connections and defined the calculating methods for hamonic currents of those systems.
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A new estimated neural networks are proposed in order to measure nonlinear road environments in realtime. This new neural networks is Error Estimated Neural Networks. The structure of it is similar to recurrent neural networks; a delayed output as the input and a delayed error between the output of plant and neural networks as a bias input. In addition, we compute the desired value of hidden layer by an optimal method instead of transfering desired values by backpropagation and each weights are updated by RLS(Recursive Least Square). Consequently, this neural networks are not sensitive to initial weights and a learning rate, and have a faster convergence rate than conventional neural networks. We can estimate nonlinear models in realtime by the proposed networks and control nonlinear models. To show the performance of this one, we control 7 degree simulation, this controller and driver were proved to be effective to drive a car in the environments of nonlinear road systems.
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Liang, Yujun;Zhang, Hongjie;Kim, Beung-Kwon;Jung, Young-Ho;Park, Jo-Yong;Myung, Kwang-Shik;Khatkar, S.P.;Han, Sang-Do 578
A bright and highly monochromatic red organic electroluminescent device based on a poly(N-vinylcarbazole) host was made. The device structure consists of poly(N-vinylcarbazole) dispersed with a europium complex as an emitting layer and a hole blocking layer of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The EL cell exhibited just characteristic emission of europium ion. -
Jung, Young-Ho;Park, Jin-Won;Park, Jo-Yong;Khatkar, S.P.;Taxak, V.B.;Myung, Kwang-Shik;Han, Sang-Do 581
A new method for the preparation of lanthanide ions activated strontium aluminates phosphor by combustion method has been proposed. Combustion method consist of the redox reactions between the respective metal nitrates and urea in a preheated funace at$500^{\circ}C$ . The luminescence behavior of the phosphor was studied and compared with corresponding phosphor prepared by conventional method. Effect of$Mg^{2+}$ ion concentration in strontium aluminate phosphor was investigated and the maximum luminescence of about$100cd/m^2$ was obtained. This method gave better brightness and small size to the phosphor than made by conventional method. -
The materials showing high structure dispersity are developed on the quartz base and they are obtained by mechano-chemical technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, contain a dielectric material as a canγing nucleus, particularly the quartz on that surface one or more layers of different compounds are synthesized having thickness up to 10~50 nm and showing magnetic, electrical and other properties.
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Soh, Dae-Wha;Kovtunets, V.A.;Kupchishin, A.I.;Mun, G.A.;Nurkeeva, Z.S.;Akhmetkalieva, G.T.;Khutoryanskiy, V.V. 588
Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. The effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on poly(vinyl ether of ethyleneglycol : PVEEG) have been studied for investigating mechanical and electric property of polymer composites applications. -
New polymeric hydrogels based on vinyl ethers have been synthesized by the
${\gamma}$ -initiated polymerization method. Their physical chemistry and physical mechanical properities have been studied. It has been shown that structure and swelling behavior of the hydrogels can be regulated by the changing of synthesis conditions nature of monomers. Novel stimuli-sensitive polymers have been synthesized by the varying of macrochains hydrophilic-hydrophobic balance. The some biomedical aspects of application of hydrogels in capacity of drain aging polymeric materials in ophthalmology surgery, implants in plastic surgery as well as drug delivery systems have been investigated. -
An easy elevator for learning originated is opened to compare the existed learning equipment, and it had a high studying efficient that the sequence control circuit can opens and closes with the wire. The structure of equipment to be controlled from the first floor to the fifth floors is demonstrated a constructive apparatus by a lamp atc to express the function of the open-close of the door according to the cage moving with a mechanical actuation of the forward-reverse breaker and the motor of load and a mechanical actuation of hand-operation control components of push-button S/W and L/S and relay etc. These components let connects each other in order to control of the elevator function with the auto program and the designed sequence control circuit. Consequent1y the process of these functions of 1~5steps could operates the cage with an auto program of the elevator and the sequence control circuit. The sequence control circuit is controlled by the step of forward and reverse to follow as that the sensor function of the L/S1~L/S5 let posit with the control switchs of S/W1~S/W5 of PLC testing panel and switchs of S/W1~S/W5 installed on the transparent acryl plate of the frame. In here, improved apparatus is a hand-auto operation combined learning equipment to study the principle and a technique of the originated sequence control circuit and the auto program of PLC.