• Title/Summary/Keyword: H-Si(100)

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Studies of the Mullite-Cordierite Composites as a Substrate Material (기판재료로서의 물라이트-코디어라이트 복합재료에 관한 특성)

  • 김경용;김윤호;정형진;김석수;김병호
    • Journal of the Korean Ceramic Society
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    • v.27 no.3
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    • pp.394-400
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    • 1990
  • Mullite and cordierite were prepared by the sol-gel route. Boehmite, fumed silica and Mg(NO3)2$.$6H2O were their starting materials. Mullite and cordierite powder were mixed by various weight percent. These mixed sols were ball-milled for 48hrs, dried at 100$^{\circ}C$, pressed, cold isostatic pressed and sintered at 1490$^{\circ}C$ for 2hrs. Mullite-cordierite composites sintered at 1490$^{\circ}C$ for 2hrs had>98% of theoretical density. Bending strength of the sintered bodies were 329-249MPa, dielectric constant 7.1-6.7 at 1MHz and thermal expansion coefficient at 800$^{\circ}C$ was matched with Si in the range of 30-35wt% cordierite.

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Fabrication of Tip of Probe Card Using MEMS Technology (MEMS 기술을 이용한 프로브 카드의 탐침 제작)

  • Lee, Keun-Woo;Kim, Chang-Kyo
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.4
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    • pp.361-364
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    • 2008
  • Tips of probe card were fabricated using MEMS technology. P-type silicon wafer with $SiO_2$ layer was used as a substrate for fabricating the probe card. Ni-Cr and Au used as seed layer for electroplating Ni were deposited on the silicon wafer. Line patterns for probing devices were formed on silicon wafer by electroplating Ni through mold which formed by MEMS technology. Bridge structure was formed by wet-etching the silicon substrate. AZ-1512 photoresist was used for protection layer of back side and DNB-H100PL-40 photoresist was used for patterning of the front side. The mold with the thickness of $60{\mu}m$ was also formed using THB-120N photoresist and probe tip with thickness of $50{\mu}m$ was fabricated by electroplating process.

Selective Area Epitaxy of GaAs and InGaAs by Ultrahigh Vacuum Chemical vapor Deposition(UHVCVD) (Ultrahigh Vacuum Chemical Vapor Deposition (UHVCVD)법에 의한 GaAs와 InGaAs 박막의 선택 에피택시)

  • 김성복
    • Journal of the Korean Vacuum Society
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    • v.4 no.3
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    • pp.275-282
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    • 1995
  • III족 원료 가스로 triethylgallium(TEGa)과 trimethylindium(TMIn)을 사용하고 V족 원료 가스로 사전 열 분해하지 않은 arsine(AsH3)과 monoethylarsine(MEAs)을 사용하여 ultrahigh vacuum chemical vapor deposition(UHVCVD)법으로 Si3N4로 패턴된 GaAs(100)기판 위에 GaAs와 InGaAsqkr막을 선택적으로 에피택시 성장을 하였다. V족 원료 가스를 사전 열 분해하지 않으므로 넓은 성장 온도 구간과 V/lll 비율에서도 선택적으로 박막이 성장되었다. 또한 선택 에피택시의 성장 메카니즘을 규명하기 위하여 다양한 filling factor(전체면적중 opening된 면적의 비율)를 가지는 기판을 제작하여 성장에 사용하였다. UHVCVD법에서는 마스크에 면적중 opening된 면적의 비율)를 가지는 기판을 제작하여 성장에 사용하였다. UHVCVD법에서는 마스크에 입사된 분자 상태의 원료 기체가 탈착된 후 표면 이동이나 가스 상태의 확산과정 없이 마스크로부터 제거되므로 패턴의 크기와 모양에 따른 성장 속도의 변화나 조성의 변화가 없을 뿐만 아니라 chemical beam epitaxy(CBE)/metalorganic molecular beam epitaxy(MOMBE)법에서 알려진 한계 성장온도 이하에서 선택 에피택시 성장이 이루어졌다.

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Effects of Gas Flow Variables on the Crystal Growth of Diamond in Hot Filament-Assisted CVD (고온 필라멘트 다이아몬드 CVD에서 기체유동변수가 결정성장에 미치는 영향)

  • 서문규;이지화
    • Journal of the Korean Ceramic Society
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    • v.31 no.1
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    • pp.88-96
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    • 1994
  • Hot filament-assisted CVD was carried out to deposit diamond films on Si(100) substrate at 90$0^{\circ}C$ using a 1% CH4-H2 mixture gas. Deposition was made at various conditions of mass flow rate of the feed gas (30~1000 sccm), pressure (2.5~300 Torr), and filament-substrate distance (4~15 mm), and the deposited films were characterized by SEM, XRD, and Raman spectroscopy. As the flow rate increases, the growth rate also increased but the crystallinity of the film was degraded. A longer filament-substrate distance simply caused both the growth rate and the crystallinity to become poorer. On the other hand, the pressure variation resulted in a maximum growth rate of 2.6 ${\mu}{\textrm}{m}$/hr at 10 Torr and the best film quality around 50 Torr, exhibiting an optimum condition. The observed trends were interpreted in terms of the flow velocity-dependent pyrolysis reaction efficiency and mass transport through the boundary layer.

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Ferromagnetic Domain Behaviors in Mn doped ZnO Film

  • Soundararajan, Devaraj;Santoyo-Salazar, Jaime;Ko, Jang-Myoun;Kim, Ki-Hyeon
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.216-219
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    • 2011
  • Mn doped ZnO films were prepared on Si (100) substrates using sol-gel method. The prepared films were annealed at $550^{\circ}C$ for decomposition and oxidation of the precursors. XRD analysis revealed the presence of ZnMnO hexagonal wurtzite phase along with the presence of small quantity of $ZnMn_2O_3$ secondary phase and poor crystalline nature. The 2D, 3D views of magnetic domains and domain profiles were obtained using magnetic force microscopy at room temperature. Rectangular shaped domains with an average size of 4.16 nm were observed. Magnetic moment measurement as a function of magnetic field was measured using superconducting quantum interference device (SQUID) magnetometry at room temperature. The result showed the ferromagnetic hysteresis loop with a curie temperature higher than 300 K.

a-Si:H Photosensor Using Cr silicide Schottky Contact

  • Hur, Chang-Wu
    • Journal of information and communication convergence engineering
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    • v.4 no.3
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    • pp.105-107
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    • 2006
  • Amorphous silicon is a kind of optical to electric conversion material with current or voltage type after generating a numerous free electron and hole when it is injected by light. It is very effective technology to make schottky diode by bonding thin film to use optical diode. In this paper, we have fabricated optical diode device by forming chrome silicide film through thermal processing with thin film($100{\AA}$) having optimal amorphous silicon. The optimal condition is that we make a thin film by using PECVD(Plasma Enhanced Chemical Vapor Deposition) to improve reliability and characteristics of optical diode. We have obtained high quality diode by using chrome silicide optical diode from dark current and optical current measurement compared to previous method. It makes a simple process and improves a good reliability.

Physicochemical Properties of Citrus miyakawa wase Produced in Cheju, and Citrus Jam-making (제주산 궁천조생의 특성과 젤리화 식품의 제조)

  • 고정삼;고남권
    • Food Science and Preservation
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    • v.2 no.1
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    • pp.139-146
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    • 1995
  • Soluble solids and total carbohydrates of Citrus miyakawa wase harvested middle of November 1993 Topyung-Dong, Seogwipo-si, and Cheju were 10.7 and 8.57%, and carbohydrate was consisted of about 1/2 sucrose, 1/4 glucose and 1/4 fructose, respectively. Acid content of citrus Juice was 1.04%, and citric acid was 74.27% of total organic acids. Fruit weight, peel thickness, soluble solids, pH, hardness and edible part ratio had a good correlation in linear function with increasing fruit size. Total carbohydrate, reducing sugar and vitamin C of citrus jam made on optimum conditions were 65.33%, 27.98%, and 51.40mg/100g , respectively. Microbial growth on the products were not recognized at 3$0^{\circ}C$ for a month. Compared with other related citrus jellying products, the test sample was excellent in appear ance, taste and total preference degree on sensory evaluation.

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Removal of Ethylene Over KMnO4/Silica-alumina: Effect of Synthesis Methods and Reaction Temperatures (KMnO4/실리카-알루미나 상에서 에틸렌 제거: 합성 방법과 반응온도의 영향)

  • Cho, Min-Whee;Yoon, Songhun;Park, Yong-Ki;Choi, Won Choon;Kim, Hee Young;Park, Seungkyu;Lee, Chul Wee
    • Applied Chemistry for Engineering
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    • v.20 no.4
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    • pp.407-410
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    • 2009
  • 18~19 wt% $KMnO_4$/$SiO_2-Al_2O_3$ with Si/Al = 1/5 and 1/10, and 20 wt% $KMnO_4$/$Al_2O_3$ were prepared by solvent evaporation method. Catalytic activity of ethylene abatement over those samples were evaluated and compared under the conditions of GHSV $1125h^{-1}$, ethylene gas (ethylene 0.2%, air 99.8%, relative humidity 50%) at 30, 40, 60 and $120^{\circ}C$ using a fixed-bed reactor. $KMnO_4$/$SiO_2-Al_2O_3$ was showed better performance than $KMnO_4$/$Al_2O_3$ by 170~210% at 30, $40^{\circ}C$, and by 60% at 60, $150^{\circ}C$, respectively.

Incident Angle Dependence of Quantum Efficiency in c-Si Solar Cell or a-Si Thin Film Solar Cell in BIPV System (광 입사각이 BIPV에 적용되는 단결정 또는 비정질 실리콘 태양전지의 양자효율에 미치는 영향)

  • Kang, Jeong-Wook;Son, Chan-Hee;Cho, Guang-Sup;Yoo, Jin-Hyuk;Kim, Joung-Sik;Park, Chang-Kyun;Cha, Sung-Duk;Kwon, Gi-Chung
    • Journal of the Korean Vacuum Society
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    • v.21 no.1
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    • pp.62-68
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    • 2012
  • The conversion efficiency of solar cells depending on incident angle of light is important for building-integrated photovoltaics (BIPV) applications. The quantum efficiency is the ratio of the number of charge carriers collected by the solar cell to the number of photons of a given energy shining on the solar cell. The analysis of angle dependence of quantum efficiencies give more information upon the variation of power output of a solar cell by the incident angle of light. The variations in power output of solar cells with increasing angle of incidence is different for the type of cell structures. In this study we present the results of the quantum efficiency measurement of single-crystalline silicon solar cells and a-Si:H thin-film solar cells with the angle of incidence of light. As a result, as the angle of incidence increases in single-crystalline silicon solar cells, quantum efficiency at all wavelength (300~1,100 nm) of light were reduced. But in case of a-Si:H thin-film solar cells, quantum efficiency was increased or maintained at the angle of incidence from 0 degree to about 40 degrees and dramatically decrease at more than 40 degrees in the range of visible light. This results of quantum efficiency with increasing incident angle were caused by haze and interference effects in thin-film structure. Thus, the structural optimization considering incident angle dependence of solar cells is expected to benefit BIPV.