• Title/Summary/Keyword: Si 분포

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스퍼터링 방식으로 형성시킨 코발트 실리사이드 박막의 형성 및 특성

  • 조한수;백수현;황유상;최진석;정주혁
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1993.05a
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    • pp.62-63
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    • 1993
  • Salicide(Self-aligned) CoSi$_2$의 형성을 알아보기 위하여, 단결정 실리콘 기판내에 불순물 주입에 따른 실리사이드의 형성영향을 알아보는, As,BF$_2$를 주입 한 시편과, 코발트와 SiO$_2$를 증착한 시편을 준비하였다. RF sputtering 방식으로 각각의 기판위에 코발트를 증착 한 후 Rapid Thermal Annealing(RTA) 온도 400-100$0^{\circ}C$영역에서 20초 동안 열처리 하였다. RTA 온도 80$0^{\circ}C$에서 비저항이 약 18$\mu$$\Omega$-cm정도의 CoSi$_2$를 형성 시켰으며 SEM 과 $\alpha$-step 으로 확인된 Si 기판과 코발트 실리사이드의 계면 roughness 및 surface roughness는 우수하였고, CoSi$_2$의 두께 증가에 따른 실리콘 소모량의 증가에 따라 기판내에 있던 As,BF$_2$ 이온들이 실리사이드내로 재분포 되는 현상을 보였다.CoSi$_2$/Si 계면간의 열적안정성은 $N_2$분위기로 30분간 Furnace Annealing 온도 100$0^{\circ}C$까지 CoSi$_2$의 응집화 현상이 일어나지 않았다.

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Physico-Chemical Characteristics of Water and Distribution of Vascular Hydrophytes in the West Nakdong River, South Korea (서낙동강 수질의 이화학적 특성과 수생관속식물의 분포)

  • 윤해순;김구연;김승환;이원화;이기철
    • The Korean Journal of Ecology
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    • v.25 no.5
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    • pp.305-313
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    • 2002
  • The physico-chemical characteristics of water and sediment, and structures of vegetation of the vascular hydrophytes were investigated in the West Nakdong River. Water quality was eutrophic according to the mean values and the ranges of water properties such as pH, DO, BOD, chlorophyll a, total nitrogen and phosphate, and other nutrients. A few cases were hypereutrophic for chlorophyll a level in summer. Soil reaction was weak acid. Composition of sediment was mainly sand except in SI(Sinan chideung) of which was mainly clay, and SU(Suan chideung) of which was mainly silt. Flora of vascular hydrophyte had 26 species and 1 variety comprising 16 families. Trapa japonica was dominant species in the sites of DU(Dunchido), GA(Garak chideung) and SU. Nymphoides peltata and Hydrocharis dubia dominated in DA and SI, respectively. Species diversity and evenness were relatively high in SI and SU but dominance was high in DA. After June, water lettuce(Pistia stratiotes) and water hyacinth(Eichhornia crassipes) were flowed from tributary to the river. Standing crop of macrohydrophytes was high in DA from April to August, but it showed maximum standing crop (445g·dw/㎡) in DU after disturbance by explosive growth of exotic plants in October. In comparison with those in 1985, total productivities in DU and GA decreased to 33.5%, and the reduction ratio of dominant species, Trapa japonica was 56.7%. Najas marina, N. minor, Myriophyllum spicatum and Nymphoides indica have disappeared ever since the Nakdong barrage was constructed in the Nakdong river. They were divided into three groups (GA-SU-DU, DA, SI) by cluster analysis. Introduction of the exotic species in this river caused decreasing of endemic plants including endangered species Euryale ferox and rare species Hydocharis dubia, and food plants for waterfowl such as Trapa japonica, Vallisneria asiatica and Potamogeton crispus.

Microstructures and electron mobilities of $Si/Si_{1-x}Ge_x$ MODFET structures grown by gas-source MBE (가스원 분자선 에피택시 증착법에 의한 $Si/Si_{1-x}Ge_x$ MODFET 구조의 미세조직과 전기이동도에 관한 연구)

  • 이원재
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.207-211
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    • 1999
  • $Si/Si_{1-x}Ge_x$ MODFET structures, incorporating linearly-graded buffer layers have been grown by GaS Source Molecular Beam Epitaxy. The growth temperature of the graded layers has not significantly changed the distribution of misfit dislocation. However, the surface undulation and surface defects were increased with increasing growth temperature. In $Si/Si_{1-x}Ge_x$ MODFET structures, the densities of misfit dislocations near the Si-active layers were considerably reduced in comparison with the region of graded layers. The electron mobility of $Si/Si_{1-x}Ge_x$ MODFET structure has increased with lowering the growth temperature.

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Fabrication of Si quantum dots superlattice embedded in SiC matrix (SiC 매트릭스를 이용한 실리콘 양자점 초격자 박막 제조)

  • Kim, Hyun-Jong;Moon, Ji-Hyun;Cho, Jun-Sik;Chang, Bo-Yun;Ko, Chang-Hyun;Park, Sang-Hyun;Yoon, Kyung-Hoon;Song, Jin-Soo;O, Byung-Sung;Lee, Jeong-Chul
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.163-166
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    • 2009
  • 다중접합 초 고효율 태양전지 제조를 위해 SiC 매트릭스를 이용한 실리콘 양자점 초격자 박막을 제조하고 특성을 분석하였다. $SiC/Si_{1-x}C_x$(x ~ 0.31)로 실리콘 양자점 초격자 박막을 Si과 C target을 이용한 co-sputtering법으로 초격자 박막을 제조하고, $1000^{\circ}C$에서 20분간 열처리를 하였다. high resolution transmission electron microscopy 사진으로 약1~7nm 크기인 양자점 생성과 분포 밀도를 확인할 수 있었으며, grazing incident X-ray diffraction (GIXRD)를 통해서 Si(111)과 $\beta$-SiC(111)이 생성되었음을 알 수 있었다. Auger electron spectroscopy (AES)측정에서 stoichiometric SiC층과 Si-rich SiC층의 Si 원자농도 (56%, 69%)와 C 원자 농도 (44%, 31%)를 알 수 있었으며, Fourier transform infra-red spectroscopy (FTIR)측정에서 SiC 픽의 위치가 767에서 $800cm^{-1}$으로 이동하는 것을 알 수 있었다.

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Design and Fabrication of microheaters based oil polycrystalline 3C-SiC with large uniform-temperature area for high temperature (다결정 3C-SiC 기반으로 한 넓은 범위에서 균일한 온도 분포를 갖는 초고온용 마이크로 히터 설계 및 제작)

  • Jeong, Jae-Min;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.214-215
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    • 2009
  • This paper presents the fabrication and characteristics of microheaters, built on AlN(0.1 um)/3C-SiC(1 um) suspended membranes. Pt was used as microheater and temperature sensor materials. The results of simulated are shown that AlN/3C-SiC membrane has more large uniform-temperature area than $SiO_2$/3C-SiC membrane. Resistance of temperature sensor and power consumption of microheater were measured and calculated. Pt microheater generates the heat of about $550^{\circ}C$ at 340 mW and TCR of Pt temperature sensor is about 3188 ppm/$^{\circ}C$.

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Thermal Characteristics of Microheater for Gas Sensors (가스센서용 마이크로 히터의 발열특성)

  • Choi, Woo-Chang;Choi, Hyek-Hwan;Kwon, Tae-Ha;Lee, Myong-Kyo
    • Journal of Sensor Science and Technology
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    • v.7 no.5
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    • pp.356-363
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    • 1998
  • Using the results analyzed by FEM(Finite Element Method). the microheaters with the stress-balanced $Si_3N_4$(150 nm)/$SiO_2$(300 nm)/$Si_3N_4$(150 nm) diaphragms were fabricated by silicon micromachining techniques. Pt was used as microheater materials. Pt temperature sensor was fabricated to measure the temperature of microheaters. Resistance of temperature sensor and power dissipation of microheater were measured and calculated at the various temperatures. The thermal distribution of heater was examined by a IR thermoviewer. Measured and simulated results are compared and analyzed. The temperature coefficient of resistance of heater was about $0.00379/^{\circ}C$. Pt heater showed the power dissipation of about 51 mW at $300^{\circ}C$ and a uniform thermal distribution on the surface.

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Preparation and Property. of $TiO_2-SiO_$ Optical Thin Films with the Mixture Ratio (혼합비에 따른 $TiO_2-SiO_$ 광학 박막의 제작 및 특성)

  • 이학준;안영욱;윤영진;김의정;한성홍
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.196-197
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    • 2002
  • 졸-겔법은 비정질이나 결정질의 산화물 박막을 제작하는 유용한 방법중 하나이다.(1) 또한 졸-겔법은 제작하고자 하는 특성의 시편을 비교적 쉽게 구현할 수 있다는 장점이 있다. TiO$_2$와 SiO$_2$ 박막은 비교적 큰 굴절률 차이를 갖고 있어 혼합비에 따라 넓고 완만한 굴절률 분포를 가진다.(2) 이것은 박막이 원하는 광학적 특성을 가지게 하여 광학이나 촉매 분야에 응용할 수 있는 가능성이 크다는 것을 의미한다. (중략)

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Conservation of an Endangered Corylopsis coreana $U_{yeki}$ in and Ex Situ and Development of Cooperative Model within Local Community I. Study for a Characteristic of Distribution Pattern in Corylopsis coreana $U_{yeki}$ (보호종인 히어리의 자생지내외 보전과 지역사회 헙력 모델 개발 I. 히어리 분포지 특성에 관한 연구)

  • Lim Dong-Ok;Hwang In-Chun;Choung Heung-lak
    • Korean Journal of Environment and Ecology
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    • v.19 no.2
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    • pp.162-176
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    • 2005
  • This study was carried out as a field survey and a review of articles to investigate a characteristic of the distribution pattern in Korean endemic Corylopsis coreana. Distribution of Corylopsis coreana was found in Boseung-gun, Gwangyang-si, Suncheon-si, Jeumam-myeon Goheung-gun, Ganjeon-myeon Gurye-gun, Mt, Cheongwan Jangheung-gun, Nogodan Mt. Jiri in Jeollanam-do, Mt. Cheonhwang Namwon-si and Beamsagol and Banyabong Mt. Jiri in Jeollabuk-do, Sancheong-gun, hadong-gun and Namhea-gun in Gyeongsangnam-do and Mt. Backun, Pocheon-si in Gyeonggi-do. Total flora in the distribution region of Coryloplsis coreana was recorded as 242 taxa; 70 families, 159 genus, 216 species, 22 varieties, 4 forma. Ratio of taxonomic categories was consisted of Pteridophyte $5.8\%$, Gymnosperm $3.7\%$, Dicotyledon $18.6\%$ and Monocotyledon $71.9\%$. Ratio of Life cycle styles was Annual $1.7\%$ and Perennial $93.3\%$. Ratio of growth habit was appeared to Herb $44.2\%$, Vine $12.4\%$, Shrub $17.8\%$ and Tree $25.6\%$. The distribution region of Corylopsis coreana found to typical type which distribute in N, NE or NW slope. The native Corylopsis coreana of Sinjeonri Sungju-eup in Jellanam-do appeared to have a declining tendency which was caused by influence of tree lager.