• Title/Summary/Keyword: conductor

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The Study of Formation of Ti-silicide deposited with composite target(I) (Composite target으로 증착된 Ti-silicide의 형성에 관한 연구(I))

  • Choe, Jin-Seok;Gang, Seong-Geon;Hwang, Yu-Sang;Baek, Su-Hyeon;Kim, Yeong-Nam;Jeong, Jae-Gyeong;Mun, Hwan-Gu;Sim, Tae-Eon;Lee, Jong-Gil
    • Korean Journal of Materials Research
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    • v.1 no.3
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    • pp.168-174
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    • 1991
  • Ti-silicide was deposited by sputtering the composite target($TiSi_{2.6}$) on single-Si wafers and oxide on them. The heat treatment temperatures by rapid thermal annealing(RTA) have been varied in the range of $600-850^{\circ}C$ for 20seconds. It was not until RTA temperature was $800^{\circ}C$ that a stable $TiSi_2$ was formed, and the value of resistivity of that phase was $27~29{\mu}{\Omega}-cm$, which seems a little higher than that formed by the reactive method. The result of x-ray diffraction peals showed that till $750^{\circ}C$, C49 $TiSi_2$ phase was dominant, but at $800^{\circ}C$, at last, the phase was transformed into a stable C54 $TiSi_2$ phase. And, the result of x-ray photoeletron spectroscopy(XPS) measurements showed that the composition ratio of Ti and Si was 2 1 in the case of specimens treated at $800^{\circ}C$, The surface roughness of $TiSi_2$, which was condidered a weak point, was improved to a superior value of $17{\pm}1nm$, therefore increasing the possibility of applying $TiSi_2$ to semiconductor devices.

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Electrical Property of the Li2O-2SiO2 Glass Sintered by Spark Plasma Sintering (Spark Plasma Sintering으로 제조한 Li2O-2SiO2 유리 소결체의 전기적 특성)

  • Yoon, Hae-Won;Song, Chul-Ho;Yang, Yong-Seok;Yoon, Su-Jong
    • Korean Journal of Materials Research
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    • v.22 no.2
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    • pp.61-65
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    • 2012
  • A $Li_2O-2SiO_2$ ($LS_2$) glass was investigated as a lithium-ion conducting oxide glass, which is applicable to a fast ionic conductor even at low temperature due to its high mechanical strength and chemical stability. The $Li_2O-2SiO_2$ glass is likely to be broken into small pieces when quenched; thus, it is difficult to fabricate a specifically sized sample. The production of properly sized glass samples is necessary for device applications. In this study, we applied spark plasma sintering (SPS) to fabricate $LS_2$ glass samples which have a particular size as well as high transparency. The sintered samples, $15mm\phi{\times}2mmT$ in size, ($LS_2$-s) were produced by SPS between $480^{\circ}C$ and $500^{\circ}C$ at 45MPa for 3~5mim, after which the thermal and dielectric properties of the $LS_2$-s samples were compared with those of quenched glass ($LS_2$-q) samples. Thermal behavior, crystalline structure, and electrical conductivity of both samples were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and an impedance/gain-phase analyzer, respectively. The results showed that the $LS_2$-s had an amorphous structure, like the $LS_2$-q sample, and that both samples took on the lithium disilicate structure after the heat treatment at $800^{\circ}C$. We observed similar dielectric peaks in both of the samples between room temperature and $700^{\circ}C$. The DC activation energies of the $LS_2$-q and $LS_2$-s samples were $0.48{\pm}0.05eV$ and $0.66{\pm}0.04eV$, while the AC activation energies were $0.48{\pm}0.05eV$ and $0.68{\pm}0.04eV$, respectively.

Characterization Method for Testing Circuit Patterns on MCM/PCB Modules with Electron Beams of a Scanning Electron Microscope (MCM/PCB 회로패턴 검사에서 SEM의 전자빔을 이용한 측정방법)

  • Kim, Joon-Il;Shin, Joon-Kyun;Jee, Yong
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.9
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    • pp.26-34
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    • 1998
  • This paper presents a characterization method for faults of circuit patterns on MCM(Multichip Module) or PCB(Printed Circuit Board) substrates with electron beams of a SEM(Scanning Electron Microscope) by inducing voltage contrast on the signal line. The experimentation employes dual potential electron beams for the fault characterization of circuit patterns with a commercial SEM without modifying its structure. The testing procedure utilizes only one electron gun for the generation of dual potential electron beams by two different accelerating voltages, one for charging electron beam which introduces the yield of secondary electron $\delta$ < 1 and the other for reading beam which introduces $\delta$ > 1. Reading beam can read open's/short's of a specific net among many test nets, simultaneously discharging during the reading process for the next step, by removing its voltage contrast. The experimental results of testing the copper signal lines on glass-epoxy substrates showed that the state of open's/short's had generated the brightness contrast due to the voltage contrast on the surface of copper conductor line, when the net had charged with charging electron beams of 7KV accelerating voltages and then read with scanning reading electron beams of 2KV accelerating voltages in 10 seconds. The experimental results with Au pads of a IC die and Au plated Cu pads of BGA substrates provided the simple test method of circuit lines with 7KV charging electron beam and 2KV reading beam. Thus the characterization method showed that we can test open and short circuits of the net nondestructively by using dual potential electron beams with one SEM gun.

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Characteristics of amorphous IZTO-based transparent thin film transistors (비정질 IZTO기반의 투명 박막 트렌지스터 특성)

  • Shin, Han-Jae;Lee, Keun-Young;Han, Dong-Cheul;Lee, Do-Kyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.151-151
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    • 2009
  • Recently, there has been increasing interest in amorphous oxide semiconductors to find alternative materials for an amorphous silicon or organic semiconductor layer as a channel in thin film transistors(TFTs) for transparent electronic devices owing to their high mobility and low photo-sensitivity. The fabriction of amorphous oxide-based TFTs at room temperature on plastic substrates is a key technology to realize transparent flexible electronics. Amorphous oxides allows for controllable conductivity, which permits it to be used both as a transparent semiconductor or conductor, and so to be used both as active and source/drain layers in TFTs. One of the materials that is being responsible for this revolution in the electronics is indium-zinc-tin oxide(IZTO). Since this is relatively new material, it is important to study the properties of room-temperature deposited IZTO thin films and exploration in a possible integration of the material in flexible TFT devices. In this research, we deposited IZTO thin films on polyethylene naphthalate substrate at room temperature by using magnetron sputtering system and investigated their properties. Furthermore, we revealed the fabrication and characteristics of top-gate-type transparent TFTs with IZTO layers, seen in Fig. 1. The experimental results show that by varying the oxygen flow rate during deposition, it can be prepared the IZTO thin films of two-types; One a conductive film that exhibits a resistivity of $2\times10^{-4}$ ohm${\cdot}$cm; the other, semiconductor film with a resistivity of 9 ohm${\cdot}$cm. The TFT devices with IZTO layers are optically transparent in visible region and operate in enhancement mode. The threshold voltage, field effect mobility, on-off current ratio, and sub-threshold slope of the TFT are -0.5 V, $7.2\;cm^2/Vs$, $\sim10^7$ and 0.2 V/decade, respectively. These results will contribute to applications of select TFT to transparent flexible electronics.

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An Analysis in Optimum Coupling Method of Cylindrical Dielectric Resonator Filter Designed by Non-decaying Mode Analysis (Non-decaying 모드 해석을 이용해서 설계한 원통형 유전체 공진기 여파기의 최적 결합 방법에 대한 분석)

  • Lee, Won-Hui;Park, Chang-Won;Kim, Tai-Shin;Hur, Jung;Lee, Sang-Young
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.7
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    • pp.14-21
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    • 2001
  • In this paper, we designed and fabricated C-band bandpass filter using dielectric resonators. From waveguide cutoff frequency which applied the region between adjacent dielectric resonators, the height of cavity is determined. The cavity's diameter is determined to the twice of dielectric resonator? diameter considering the conductor loss. The resonant frequency of the DR cavity is calculated with non decaying mode analysis. Conventionally, cylindrical dielectric resonator is analysed by Cohn's model which use the decaying mode in the region between dielectric resonator wall and circular cavity wall, which is an approximated method. The external quality factor, $Q_{ex}$ has found with simulation result using Ansoft's Maxwell simulation tool. The designed filter using dielectric resonators with dielectric constant of 45 has the passband center at 5.065GHz. The bandpass filter using dielectric resonators has about 1dB insertion loss, 20MHz bandwidth and more than 30dB attenuation at $f_0+15MHz$.

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Oxygen Permeation and Mechanical Properties of La0.6Sr0.4Co0.2Fe0.8O3-δ Membrane with Different Microstructures (미세구조에 따른 La0.6Sr0.4Co0.2Fe0.8O3-δ 분리막의 산소투과 및 기계적 특성)

  • Lee, Shi-Woo;Lee, Seung-Young;Lee, Kee-Sung;Woo, Sang-Kuk;Kim, Do-Kyung
    • Journal of the Korean Ceramic Society
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    • v.39 no.10
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    • pp.994-1000
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    • 2002
  • Oxygen permeability and the mechanical properties of mixed ionic-electronic conductive $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ perovskite-type membrane, fabricated by solid state reaction, were investigated with regard to microstructure. The microstructure of the membrane was controlled by changing the sintering temperature and holding time. The average grain size and relative density were evaluated as a function of sintering conditions. As the fraction of grain boundary decreased, oxygen permeability showed a tendency to increase. Especially the maximum oxygen flux of 0.37 ml/$cm^2$${\cdot}$min was measured for the specimen sintered at 1300${\circ}C$ for 10 h, which has high density and relatively large grain size. Fracture strength was dependent on the relative density of sintered body, while fracture toughness increased with average grain size.

Students' Responses on the Supporting or Conflicting Evidences on Thier Preconception (학생 선개념을 지지하는 증거와 반증하는 증거에 대한 학생의 반응)

  • Park, Jong-Won;Kim, Ik-Gyun;Lee, Moo;Kim, Myung-Whan
    • Journal of The Korean Association For Science Education
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    • v.18 no.3
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    • pp.283-296
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    • 1998
  • This study was to identify middle school and college of education students' preconceptions about dielectric polarization and explore the students' reponses on the supporting or conflictual evidences on their preconceptions by letting them observe the demonstrations using electroscope, charged material, six conductor rods and six insulator rods. Letting students select the demonstrations to be observed by themselves, students' evidence selection types were classified as two : to select the evidences to testify their uncertain preconceptions, and to obtain the confirmation evidences about their preconceptions. And each evidence selection types, again, could be subclassified as three and two respectively. When students observed the conflictual observations, all accepted the observation itself. For supporting observational evidences, almost of all students showed the error of 'acceptance of antecedent' in the syllogism, that is, they did not required the succeeding supporting observations. Students' reponses on the conflictual observational evidences were classified as two: to reject the hard core of preconceptions, and to modify the students' auxiliary ideas related to the hard core with preserving the hard core. The first type reponses were, again, could be classified as three subtypes but, in all cases, students introduced new concept to explain the conflictual evidences. This responses indicated that Lakatosian rather than Popperian view is more acceptable to understand the students' reponses on the conflictual evidences. The second type reponses also were classified as three subtypes, and it was found that more middle school students than college education students were involved in this second type. That is, students who did not have perfect understanding of auxiliary ideas related with the hard core of preconceptions were more apt to change or modify theses auxiliary ideas rather than reject the hard core, this means that the quality of understanding of auxiliary ideas also take an important role in the change of hard core concept.

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Prediction of Impedance Characteristics of Multi-Layer Ceramic Capacitor Based on Coupled Transmission Line Theory (결합 전송선로 이론을 이용한 적층 세라믹 커패시터의 임피던스 특성 예측)

  • Jeon, Jiwoon;Kim, Jonghyeon;Pu, Bo;Zhang, Nan;Song, Seungjae;Nah, Wansoo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.2
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    • pp.135-147
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    • 2015
  • With the miniaturization and digitalization of electronics industry, demand for Multi-Layer Ceramic Capacitor(MLCC) has increased steadily because of its various applications such as DC Blocking, Decoupling and Filtering etc. The modeling techniques of MLCC has been studied for a long time but most of these modeling method can only be applied after measurement and this has some losses of material, time in both production stage and measurement stage. This paper proposes the modeling method which can predict the frequency characteristics of MLCC from structure data and material data in design stage. The impedance of N-Layer Capacitor can be expressed in differential mathematical form based on coupled transmission line equations. By using this formula, we can predict the impedance of MLCC. As a result, proposed modeling is correspond with simulation, and it takes much less time to obtain the result than the simulation.

Determination of Crystal Size and Microstrain of $CeO_2$ by Rietveld Structure Refinement (리트벨트 구조분석법에 의한 $CeO_2$의 결정크기 및 미세응력 결정)

  • Hwang, Gil-Chan;Choi, Jin-Beom
    • Journal of the Mineralogical Society of Korea
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    • v.21 no.2
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    • pp.201-208
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    • 2008
  • Ceria ($CeO_2$) becomes one of important functional nanomaterials and a key abrasive material for chemical-mechanical planarization (CMP) of advanced integrated circuits in silicon semi-conductor technology. Two synthetic crystalline ceria (RT735, RT835) are studied by the Rietveld structural refinement to determine crystallite size and microstrain. Rietveld indices of RT735 and RT835 indicate good fitting with $R_p(%)=8.50$, 8.34; $R_{wp}(%)=13.4$, 13.5; $R_{exp}(%)=11.3$, 11.5; $R_B(%)=2.21$, 2.36; S(GofF: Goodness of fit)=1.2, 1.2, respectively. $CeO_2$ with space group Fm3m show a=5.41074(2), 5.41130(6) ${\AA}$, V=158.406(1), 158.455(3)${\AA}^3$ in dimension. Detailed Rietveld refinement reveals that crystallite size and microstrain are 37.42(1) nm, 0.0026 (RT735) and 72.80(2) nm, 0.0013 (RT835), respectively. It also shows that crystallite size and microstrain of ceria are inversely proportional to each other.

Nanomaterials Research Using Quantum Beam Technology

  • Kishimoto, Naoki;Kitazawa, Hideaki;Takeda, Yoshihiko
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.10a
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    • pp.7-7
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    • 2011
  • Quantum beam technology has been expected to develop breakthroughs for nanotechnology during the third basic plan of science and technology (2006~2010). Recently, Green- or Life Innovations has taken over the national interests in the fourth basic science and technology plan (2011~2015). The NIMS (National Institute for Materials Science) has been conducting the corresponding mid-term research plans, as well as other national projects, such as nano-Green project (Global Research for Environment and Energy based on Nanomaterials science). In this lecture, the research trends in Japan and NIMS are firstly reviewed, and the typical achievements are highlighted over key nanotechnology fields. As one of the key nanotechnologies, the quantum beam research in NIMS focused on synchrotron radiation, neutron beams and ion/atom beams, having complementary attributes. The facilities used are SPring-8, nuclear reactor JRR-3, pulsed neutron source J-PARC and ion-laser-combined beams as well as excited atomic beams. Materials studied are typically fuel cell materials, superconducting/magnetic/multi-ferroic materials, quasicrystals, thermoelectric materials, precipitation-hardened steels, nanoparticle-dispersed materials. Here, we introduce a few topics of neutron scattering and ion beam nanofabrication. For neutron powder diffraction, the NIMS has developed multi-purpose pattern fitting software, post RIETAN2000. An ionic conductor, doped Pr2NiO4, which is a candidate for fuel-cell material, was analyzed by neutron powder diffraction with the software developed. The nuclear-density distribution derived revealed the two-dimensional network of the diffusion paths of oxygen ions at high temperatures. Using the high sensitivity of neutron beams for light elements, hydrogen states in a precipitation-strengthened steel were successfully evaluated. The small-angle neutron scattering (SANS) demonstrated the sensitive detection of hydrogen atoms trapped at the interfaces of nano-sized NbC. This result provides evidence for hydrogen embrittlement due to trapped hydrogen at precipitates. The ion beam technology can give novel functionality on a nano-scale and is targeting applications in plasmonics, ultra-fast optical communications, high-density recording and bio-patterning. The technologies developed are an ion-and-laser combined irradiation method for spatial control of nanoparticles, and a nano-masked ion irradiation method for patterning. Furthermore, we succeeded in implanting a wide-area nanopattern using nano-masks of anodic porous alumina. The patterning of ion implantation will be further applied for controlling protein adhesivity of biopolymers. It has thus been demonstrated that the quantum beam-based nanotechnology will lead the innovations both for nano-characterization and nano-fabrication.

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