• Title/Summary/Keyword: Cheongju-si

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Improved Magnetic Properties of Silicon-Iron Alloy Powder Core

  • Lee, Tae-Kyung;Kim, Gu-Hyun;Choi, Gwang-Bo;Jeong, In-Bum;Kim, Kwang-Youn;Jang, Pyung-Woo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1191-1192
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    • 2006
  • Eventhough Fe-6.5 wt.% Si alloy shows excellent magnetic properties, magnetic components made of the alloy are not totally because of its extremely low ductility. In order to overcome this demerit of alloy, 6.7 wt.% Si alloy powders were produced by gas atomization and then post-processed to form magnetic cores. By doing so, the total core loss could be minimized by reducing both hysteresis and eddy current loss. From our experiments, we were able to achive a core loss of $390mW/cm^3$ at 0.1 T and 50 kHz through proper processes and a permeability $\mu_{eff}$ of 68 at low frequency.

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Study on Availability about the Dielectric Constant of SiOC Thin Film (SiOC 박막의 허용 가능한 유전상수 설정에 대한 연구)

  • Oh, Teresa
    • Journal of the Korean Vacuum Society
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    • v.19 no.5
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    • pp.347-352
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    • 2010
  • To research the reduction of the dielectric constant depending on the ionic and electronic effects, the dielectric constant of SiOC film was obtained by C-V measurement using the structure of metal/SiOC film/Si, and $n^2$ calculated by the refractive index. The dielectric constant of SiOC film consists with dipole, ions and electrons. However, the dipole moment is ignored in the effect of dielectric constant in SiOC film. THe SiOC film was deposited by the plasma energy, and the gas precursor was dissociated and recombined. Therefore, the dielectric constant of the deposited film consisted of the polarity with ions. THe dielectric constant decreased after annealing process, because of the evaporation of OH hydroxyl group with polarity. The ideal SiOC film as low-k materials was annealed film with lowering the polarity, which is suitable for physical-chemical and electrical properties as an inter layer dielectric materials.

Effects of the Bonding Structure and Thickness on the Leakage Current of Semiconductors as Insulators (반도체 절연박막의 두께변화와 결정성에 대한 누설전류의 의존성)

  • Oh, Teresa
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.12
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    • pp.7283-7286
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    • 2014
  • SiOC films were prepared as insulators for displays by sputtering at low temperatures, and the relationship with the electrical properties waaas examined. The electrical properties of SiOC films were affected by the annealing process, and SiOC films annealed at 100oC showed a significant increase in thickness and a decrease in the reflective index. XRD revealed an increase in the degree of the amorphous structure. Moreover, the capacitance and leakage current of the SiOC films annealed at 100oC decreased. These characteristics of SiOC films highlight their potential as ideal insulators. Amorphous SiOC films by the reduction of polarization are dependent on the elongation effect of the bonding lengths in the structure and the thickness. The properties of these SiOC films are suitable for low temperature displays.

Fabrication and Properties of Silicon Solar Cells using Al2O3/Si/Al2O3 Structures (Al2O3/Si/Al2O3구조를 이용한 실리콘태양전지 제작 및 특성)

  • Kim, Kwang-Ho
    • Journal of the Semiconductor & Display Technology
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    • v.14 no.4
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    • pp.45-49
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    • 2015
  • Using a combined CVD and ALD equipment system, multi-layer quantum well structures of $Al_2O_3/a-Si/Al_2O_3$ were fabricated on silicon Schottky junction devices and implemented to quantum well solar cells, in which the 1~1.5 nm thicknesses of the aluminum oxide films and the a-Si thin film layers were deposited at $300^{\circ}C$ and $450^{\circ}C$, respectively. Fabricated solar cell was operated by tunneling phenomena through the inserted quantum well structure being generated electrons on the silicon surface. Efficiency of the fabricated solar cell inserted with multi-quantum well of 41 layers has been increased by about 10 times that of the solar cell of pure Schottky junction solar cell.

Study on the Compensation of Dielectric Constant in Dielectric Materials (절연박막에서 유전상수의 보상에 관한 연구)

  • Oh, Teresa
    • Journal of the Korean Vacuum Society
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    • v.18 no.6
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    • pp.435-439
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    • 2009
  • The reason of lowering the dielectric constant of SiOC film was studied using parameters obtained from C-V measurement and refractive index. SiOC film was formed by the force of ionic bonding during the recombination of dissociated gases. Generally, the dielectric constant was obtained from the square of the refractive index or C-V measurement using the metal/insulator/Si structure. The dielectric constant consists of the ionic and electronic elements. It was researched about the dielectric constant of SiOC film using the average of the ionic and electronic elements. The dielectric constant decreased after annealing process. As deposited films trended toward the dielectric constant consisted of most ionic elements, on the other hand, annealed films mostly consisted of electronic elements. Because the effect of ionic elements reduced after annealing. Consequently, it was found that the electronic effect of SiOC film increased and the ionic effect of SiOC film decreased by the after-annealing.

Study on the Variation of Dielectronic Constant for an Organic Insulator Film (유기물 절연 박막에 대한 유전상수의 변화에 대한 연구)

  • Oh, Teresa
    • Journal of the Korean Vacuum Society
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    • v.17 no.4
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    • pp.341-345
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    • 2008
  • The SiOC film of carbon centered system was prepared using bistrimethylsilylmethane and oxygen mixed precursor by the chemical vapor deposition. The chemical properties of the SiOC film were analyzed by the contact anlge and FTIR spectra. The dielectric constant of the deposited films decreased after annealing process, and the correlation between the increasing the BTMSM/$O_2$ flow rate ratio and the dielectric constant did not exist. However, the trend of increasing or decreasing of the dielectric constant repeated and there is the correlation ship between the dielectric constant and the Si-O-C bond in the range of $950{\sim}1200\;cm^{-1}$. The dielectric constant decreased between samples with the chemical shift. The lowest dielectric constant was 1.65 at the sample, which was observed the chemical shift.

The various bonding structure of SiOC thin films attributed to the carbon density (탄소밀도의 변화가 SiOC 박막의 결합구조에 미치는 영향)

  • Oh Teresa
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.5 s.347
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    • pp.11-16
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    • 2006
  • This paper reports the correlation between dielectric constant and degree of amorphism of the hybrid type SiOC thin films. SiOC thin films were deposited by high density plasma chemical vapor deposition using bistrimethyl- silylmethane(BTMSM,$H_{9}C_{3}-Si-CH_{2}-Si-C_{3}H_{9}$) and oxygen precursors with various flow rate ratio. As-deposited film and annealed films at $400^{\circ}C$ were analyzed by XRD. The SiOC thin films were amorphous from XRD patterns. For quantitative analysis, the diffraction pattern of the samples was transformed to radial distribution function by Fourier analysis, and then compared with each other. The degree of amorphism of annealed films was higher than that of as-deposited ones. The dielectric constant varied in accordance with flow rate ratio of precursors. The lowest dielectric constant was obtained from the as-deposited film which has the highest degree of amorphism after annealing.

Advances in Absorbers and Reflectors of Amorphous Silicon Oxide Thin Film Solar Cells for Tandem Devices (적층형 태양전지를 위한 비정질실리콘계 산화막 박막태양전지의 광흡수층 및 반사체 성능 향상 기술)

  • Kang, Dong-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.2
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    • pp.115-118
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    • 2017
  • Highly photosensitive and wide bandgap amorphous silicon oxide (a-$SiO_x$:H) films were developed at low temperature ranges ($100{\sim}150^{\circ}C$) with employing plasma-enhanced chemical vapor deposition by optimizing $H_2/SiH_4$ gas ratio and $CO_2$ flow. Photosensitivity more than $10^5$ and wide bandgap (1.81~1.85 eV) properties were used for making the a-$SiO_x$:H thin film solar cells, which exhibited a high open circuit voltage of 0.987 V at the substrate temperature of $100^{\circ}C$. In addition, a power conversion efficiency of 6.87% for the cell could be improved up to 7.77% by employing a new n-type nc-$SiO_x$:H/ZnO:Al/Ag triple back-reflector that offers better short circuit currents in the thin film photovoltaic devices.

The Mediating Roles of Trust and System Quality in Achieving System Success: A System Integrator Perspective

  • JUN, Jongkun;LEE, Won-Jun;JUNG, Jongki
    • The Journal of Asian Finance, Economics and Business
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    • v.6 no.2
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    • pp.203-212
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    • 2019
  • A system Integrator (SI) makes a consortium with multiple providers of hardware and software solutions to sell an information system. The success of information systems (IS) mainly depends on establishing a trustful relationship between SI supplier and client, and delivering high-quality system. However, the determinants of trust and system quality have been investigated mostly from the perspective of s ystem buyers rather than system sellers. This study examines the influence of key variables that SI can handle to improve trust and system quality which finally leads to user satisfaction toward SI. This study adopts resource complementarity, user participation and information sharing as the key variable then builds a research model to explain their relationships to user satisfaction. Respondents are recruited from 251 firms that have built any information system in recent two years in South Korea. Results of partial least square (PLS) modeling analysis show that both resource complementarity and information sharing have positive relationships with trust. Also the relationships between trust, system quality and user satisfaction toward S.I are supported. In addition, the mediating roles of trust and system quality are identified. We discussed some of the key managerial and theoretical implications of the paper and suggested further research directions.

Electrical Characteristics of Ambipolar Thin Film Transistor Depending on Gate Insulators (게이트 절연특성에 의존하는 양방향성 박막 트랜지스터의 동작특성)

  • Oh, Teresa
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.5
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    • pp.1149-1154
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    • 2014
  • To observe the tunneling phenomenon of oxide semiconductor transistor, The Indium-gallum-zinc-oxide thin film transistors deposited on SiOC as a gate insulator was prepared. The interface characteristics between a dielectric and channel were changed in according to the properties of SiOC dielectric materials. The transfer characteristics of a drain-source current ($I_{DS}$) and gate-source voltage ($V_{GS}$) showed the ambipolar or unipolar features according to the Schottky or Ohmic contacts. The ambipolar transfer characteristics was obtained at a transistor with Schottky contact in a range of ${\pm}1V$ bias voltage. However, the unipolar transfer characteristics was shown in a transistor with Ohmic contact by the electron trapping conduction. Moreover, it was improved the on/off switching in a ambipolar transistor by the tunneling phenomenon.