• Title/Summary/Keyword: Thermal capacitance

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Characteristic of sub-cooled nitrogen cryogenic system for 6.6kV/200A Inductive Superconducting Fault Current Limiter (6.6kV/200A급 유도형 한류기용 과냉질소 냉각시스템의 특성)

  • 박동근;강형구;윤경용;주민석;김태중;고태국
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.234-236
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    • 2003
  • The cryogenic system for inductive superconducting fault current limiter (SFCL) has been investigated recently. In this investigation, the sub-cooled nitrogen cryogenic system was adopted to enhance the performance of DC reactor for 6.6㎸/200A inductive SFCL. In sub-cooled nitrogen state at 64K, the critical current value and the thermal conductivity are larger than those of saturated nitrogen state at 77K and the electrical insulation capacitance should be remarkably enhanced. The solenoid type of 84mH superconducting DC reactor was fabricated and cooled down to 64K by using sub-cooled cooling method with GM-cryocooler and rotary pump. The fabrication techniques of cryogenic system and some experimental results such as cooling down characteristic are introduced in this study. Moreover, the sub-cooled nitrogen cryogenic system was detailedly introduced in this paper.

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A Study on the Complex Accelerating Degradation and Condition Diagnosis of Traction Motor for Electric Railway (전기철도용 견인전동기의 복합가속열화 상태진단에 관한 연구)

  • 왕종배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.1
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    • pp.93-101
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    • 2002
  • In this study, the stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the C-Class(200$\^{C}$ ) insulation system of traction motors. The complex accelerative degradation was periodically performed during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, the condition diagnosis test such as insulation resistance '||'&'||' polarization index, capacitance '||'&'||' dielectric loss and partial discharge properties were investigated in the temperature range of 20 ∼ 160$\^{C}$. Relationship among condition diagnosis tests was analyzed to find a dominative degradation factor and an insulation state at end-life point.

Permittivity Characteristics of SiO/TiN Thin Film according to Coating Thickness (SiO/TiN 박막의 증착두께에 따른 유전율 특성)

  • 김창석;이우선;정천옥;김병인
    • Electrical & Electronic Materials
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    • v.10 no.6
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    • pp.570-575
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    • 1997
  • In this days, the thinner film of dielectric materials is required while its capacitance is required to be still large at the VLSI process. Most of such VLSI have MOS structures. For the research on this requirement, MOS capacitors were fabricated on the silicon wafer in four different thickness groups by RF sputtering method. SiO of the SiO/TiN film is used as the insulating layer and TiN is chosen as the barrier against the diffusion of Al which is the terminal connected by ohmic contact because TiN has the advantageous properties such as good thermal stability and very low diffusion rate in spite of its relatively low specific resistance. In this study their electrical and optical characteristics are investigated to find refractive index, absorption coefficient and Permittivity.

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A Study on the Electrical Properties of Polyimide Langmuir-Blodgett Films (폴리이미드 랭뮤어-블로젯막의 전기적 특성에 관한 연구)

  • 정순욱;임현성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.480-483
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    • 2000
  • Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electrical properties of PI LB films were investigated at room temperature. At low electric field, ohmic conduction(I∝V) was observed and the calculated electrical conductivity was about 9.7$\times$10$^{-15}$ S/cm. At high electric field, conduction(I∝V$^2$) was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of LB film was about 7.5.

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Fault Prediction & Reliability Estimation of the Traction Motor by the Complex Accelerating Degradation and Condition Diagnosis (견인전동기의 복합가속열화 상태진단에 의한 고장예측 및 신뢰성 평가)

  • 왕종배;김명룡
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.763-766
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    • 2000
  • In this paper, stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the 200 Class insulation system of traction motors. The complex accelerative degradation was performed by periods during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, condition diagnosis test such as insulation resistance & polarization index, capacitance & dielectric loss and partial discharge properties were investigated in the temperature range of 20∼160$^{\circ}C$. Relationship among condition diagnosis test was analyzed to find an dominative degradation factor and an insulation state at end-life point.

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Thickness dependence of the piezoelectric characteristic for PZT films using by rf magnetron sputtering (RF 마그네트론 스퍼터링으로 증착한 두께에 따른 PZT 박막의 강유전 특성에 관한 연구)

  • Lee, Tae-Yong;Park, Young;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.313-316
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    • 2003
  • The lead zirconate titanate, $Pb(Zr_{0:52}Ti_{0:48})O_3$, films of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$ thickness were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the rf magnetron sputtering method. The PZT films were annealed using by a rapid thermal annealing (RTA) method. The thickness dependence of the film structure, dielectric properties, Polarization-electric field hysteresis loops and capacitance-voltage characteristics were investigated over the thickness range of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$. According to the XRD patterns of the films, (110) peak intensity increases with film thickness increased. The increase of PZT films thickness leads to the decrease of the remanent polarization and the dielectric constant.

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Characterization of low-k dielectric SiOCH film deposited by PECVD for interlayer dielectric (PEDCVD로 증착된 ILD용 저유전 상수 SiOCH 필름의 특성)

  • Choi, Yong-Ho;Kim, Jee-Gyun;Lee, Heon-Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.144-147
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    • 2003
  • Cu+ ions drift diffusion in formal oxide film and SiOCH film for interlayer dielectric is evaluated. The diffusion is investigated by measuring shift in the flatband voltage of capacitance/voltage measurements on Cu gate capacitors after bias temperature stressing. At a field of 0.2MV/cm and temperature $200^{\circ}C,\;300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C$ for 10min, 30min, 60min. The Cu+ ions drift rate of $SiOCH(k=2.85{\pm}0.03)$ film is considerable lower than termal oxide. As a result of the experiment, SiOCH film is higher than Thermal oxide film for Cu+ drift diffusion resistance. The important conclusion is that SiOCH film will solve a causing reliability problems aganist Cu+ drift diffuion in dielectric materials.

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Photo and Electrical Properties of SiNx for Nano Floating Gate Memory (나노 부유 게이트 메모리 소자 응용을 위한 SiNx의 광 특성 및 전기적 특성에 대한 연구)

  • Jung, Sung-Wook;Hwang, Sung-Hyun;Yi, Jun-Sin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.130-131
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    • 2006
  • 차세대 반도체 정보기억장치로서 활발하게 연구되고 있는 나노 부유 게이트 메모리 (Nano Floating Gate Memory) 소자를 위해 필수적인 요소인 나노 크리스탈의 형성을 위하여 다양한 굴절률을 가진 실리콘 질화막 (SiNx)을 형성하고 고온 열처리 (rapid thermal annealing)를 실시하여 나노 크리스탈의 형성과 특성에 대한 연구를 진행하였다. 다양한 굴절률을 가진 실리콘 질화막을 형성한 후 나노 크리스탈의 형성을 위하여 열처리를 수행하였고, photoluminescence (PL)를 통하여 굴절률이 높은 Si-rich SiNx 박막의 고온 열처리를 수행한 실리콘 질화막으로부터 나노 크리스탈의 형성을 확인할 수 있었다. 또한 열처리한 실리콘 질화막 위에 Al을 증착하여 MIS 구조를 형성한 후 Capacitance-Voltage (C-V) 특성을 측정하였으며, $900^{\circ}C$에서 열처리한 박막에서 나노 크리스탈에 의한 메모리 효과를 확인할 수 있었다.

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Dielectric relaxation properties in the lead scandium niobate

  • Yeon Jung Kim
    • Journal of Surface Science and Engineering
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    • v.56 no.4
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    • pp.227-232
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    • 2023
  • In this study, complex admittance as a function of temperature and frequency was measured to analyze the important relaxation properties of lead scandium niobate, which is physically important, although it is not an environmentally friendly electrical and electronic material, including lead. Lead scandium niobate was synthesized by heat treating the solid oxide, and the conductance, susceptance and capacitance were measured as a function of temperature and frequency from the temperature dependence of the RLC circuit. The relaxation characteristics of lead scandium niobate were found to be affected by contributions such as grain size, grain boundary characteristics, space charge, and dipole arrangement. As the temperature rises, the maximum admittance and susceptance increase in one direction, but the resonance frequency decreases below the transition temperature but increases after the phase transition.

Microwave와 Solution ZrO2를 이용한 Metal-Oxide-Semiconductor-Capacitor 제작

  • Lee, Seong-Yeong;Kim, Seung-Tae;Jo, Won-Ju
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.206.1-206.1
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    • 2015
  • 최근에 금속산화물을 증착하는 방법으로 용액공정이 주목 받고 있다. 용액 공정은 대기압에서 매우 간단한 방법으로 복잡한 공정과정을 요구하지 않기 때문에 박막을 경제적으로 간단하게 형성할 수 있다. 하지만 용액공정을 통해 형성한 박막에는 소자의 특성을 열화 시키는 solvent와 탄소계열의 불순물을 많이 포함하고 있어 고온의 열처리가 필수적이다. 박막의 품질을 향상시키기 위해서 다양한 열처리 방법들이 이용되고 있으며, 일반적인 열처리 방법으로는 furnace를 이용한 conventional thermal annealing (CTA)이 많이 이용되고 있다. 하지만, 최근에는 microwave를 이용한 공정이 주목 받고 있다. Microwave energy는 CTA보다 효과적으로 비교적 낮은 온도에서 높은 열처리 효과를 나타낸다. 본 실험은 n-type Silicon 기판에 solution-ZrO2 산화막을 형성 후, oven baking을 한 뒤, CTA와 microwave를 이용하여 solvent와 불순물을 제거 하였다. 전기적 특성을 확인하기 위해 solution ZrO2 산화막 위에 E-beam evaporator를 이용해 Ti 금속 전극을 증착하여 Metal-Oxide-Semiconductor (MOS) capacitor를 제작하였다. 다음으로, PRECISION SEMICONDUCTOR PARAMETER ANALYZER (4156B)를 이용하여, capacitance-voltage (C-V) 특성 및 current-voltage (I-V) 특성을 비교하였다. 다음으로, CTA를 통하여 제작한 소자와 전기적 특성을 비교하였다. 그 결과, Microwave irradiation으로 열처리한 MOS capacitor 소자에서 capacitance 값과 flat band voltage, hysteresis 등이 개선되는 효과를 확인하였다. Microwave irradiation 열처리는 100oC 미만의 온도에서 공정이 이루어짐에도 불구하고 시료 내에서의 microwave 에너지의 흡수가 CTA 공정에서의 열에너지 흡수보다 훨씬 효율적으로 이루어지며, 결과적으로 ZrO2 용액의 불순물과 solvent를 낮은 온도에서 제거하여 고품질 박막 형성에 매우 효과적이라는 것을 나타낸다. 따라서, microwave irradiation 열처리 방법은 비정질 산화막이 포함되는 박막 transistor 소자 제작에 대하여 결정적인 열처리 방법이 될 것으로 기대한다.

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