• 제목/요약/키워드: residual Si

검색결과 439건 처리시간 0.021초

초미세결정립 $ Fe_{73.5}Cu_{1}Nb_{3}Si_{16.5}B_6$ 합금의 $M\""{o}ssbauer$ 효과 연구 ($M\""{o}ssbauer$ Effet Studies on Nanocrystalline $Fe_{73.5}Cu_{1}Nb_{3}Si_{16.5}B_6$ Alloy)

  • 신영남;김재경;양재석;조익한;강신규
    • 한국자기학회지
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    • 제4권1호
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    • pp.12-19
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    • 1994
  • 비정질 $Fe_{73.5}Cu_{1}Nb_{3}Si_{16.5}B_{6}$ 합금의 $552^{\circ}C$에서 등온열처리시간에 따른 결정화 거동을 $M\"{o}ssbauer$ 분광법으로 연구하였다. 열처리된 시료는 $Do_{3}-FeSi$ 초미세결정립, Cu-cluster 및 비정질이 공존함이 $M\"{o}ssbauer$ spectrum 분석에 의해 확인되었다. 결정화 초기단계에 Cu-cluster가 형성되기 때문에 FeSi 초미세결정립의 Si함량은 높아지며, 열처리시간이 60분이 될 때까지 Si함량은 감소하는데 이는 FeSi 초미세결정립의 평균초미세자기장의 증가를 일으키며, 이후 Si함량은 거의 일정하다. 60분 이후의 열처리에서 FeSi 초미세결정립과 잔류비정질의 체적분율이 미소하게 변화함에도 잔류비정질의 평균초미세자기장이 감소하는 것은 잔류비정질에서의 Nb, B원자의 존재비의 증가에 기인된다. $552^{\circ}C$에서 60분 열처리 할 경우 FeSi 초미세결정립과 잔류비정질의 초미세자기장의 방향이 모두 무질서하게 분포된다. FeSi 초미세결정립과 Cu-cluster의 Avrami지수는 각각 0.51, 0.65, 잠복기는 각각 2.4분, 0.8분, 활성화에너지는 각각 2.35 eV, 2.44 eV이며, Cu-cluster가 FeSi 초미세결정립보다 먼저 생성된다는 것은 Cu 원자가 FeSi 초미세결정립의 생성을 촉진시킨다는 해석과 부합한다.

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가솔린 기관의 공회전 시 밸브 타이밍 변경에 따른 잔류가스 유동 변화에 관한 해석적 연구 (Numerical Analysis of Flow Characteristic of Residual Gas due to Changes in Valve Timings during an Idle Operation in an SI Engine)

  • 이준호;김득상;백두성;조용석
    • 한국자동차공학회논문집
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    • 제14권6호
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    • pp.50-56
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    • 2006
  • Residual gas fraction in a combustion process is very crucial to improve combustion and cyclic variations. Especially, the residual gas fraction is strongly affected by backflow of the residual gas during the valve overlap period in an idle operation. Therefore, it is one of the most interesting that valve timings can affect flow characteristics of gas exchange process, especially during idle operation. This analysis investigates residual gas fraction with respect to valve timing changes which is critical for combustion efficiency and engine performance. Flow characteristics of residual gas by changing intake and exhaust valve timing are calculated by CFD methodology during an idle operation in an SI engine. It is analyzed that retarded EVO and advanced IVO results in the increase of valve overlap period and consequently, residual gas fraction. Futhermore, changes in IVO have stronger effects on variation of residual gas fraction.

중간층을 이용한 DLC 박막의 밀착력에 관한 연구 (Study on Adhesion of DLC Films with Interlayer)

  • 김강삼;조용기
    • 한국표면공학회지
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    • 제43권3호
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    • pp.127-131
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    • 2010
  • Adhesion of DLC film is very significant property that exhibits wear resistance, chemical inertness and high hardness when being deposited to metal substrate. This study was considered that change adhesion of DLC film produced by Plasma Enhanced Chemical Vapor Deposition can be presented through inserting interlayer (Cr, Si-C:H). The thickness of interlayer was result of changing adhesion and residual stress. It was showed that the maximum 12 N of adhesion is on DLC film of Cr interlayer, and that a tendency is to be increased residual stress depend on the thickness. DLC film of Si-C:H interlayer represented 16 N of adhesion at $1{\mu}m$, whereas adhesion is decreased when the thickness is increased. For the interlayer at multi-layer, it was the best that adhesion of Cr/Si-C:H/DLC film was 33 N. Si-C:H interlayer at DLC film controled adhesion of the whole film. It was relaxed the internal stress of DLC film produced by inserting Cr, Si-C:H interlayer.

CCD 잔존영상 분석 (A STUDY OF RESIDUAL IMAGE IN CHARGED-COUPLED DEVICE)

  • 진호;이충욱;김승리;강용범;구재림;한원용
    • Journal of Astronomy and Space Sciences
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    • 제22권4호
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    • pp.483-490
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    • 2005
  • CCD 영상센서의 경우 포화 상태를 초과하는 막대한 양의 광자가 조사될 때 $Si-SiO_2$ 접합 면에서 전하가 포획될 순 있으며 이 접합 면에 남아 있는 전하와 관련되어 잔존영상이 보일 수 있다. 이러한 잔존영상은 특히 전면조사 방식의 CCD에서 일어난다. 이 현상이 정밀 측광에 영향을 줄 수 있음에도 불구하고 잔존영상에 대한 정량적인 분석과 보고간 국내에서는 찾아보기 힘들었다. 이에 본 연구에서는 전면조사 방식의 CCD를 사용하는 레몬산천문대 관측자료의 암전자화면에서 잔존영상을 확인하고 잔존영상이 관측에 미칠 수 있는 영향을 분석해 보았다.

반응소결 SiC 재료의 미세조직 및 강도 특성 (Microstructure and Strength Property of Reaction Sintered SiC Materials)

  • 이상필;신윤석;이진경
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2004년도 학술대회지
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    • pp.380-385
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    • 2004
  • The efficiency of complex slurry preparation route for developing the high performance SiC matrix of RS-SiCf/SiC composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of nw/ten silicon were prepared with various C/SiC complex matrix slurries, which associated with both different sizes of starting SiC particles and blending ratios of starting SiC and carbon particles. The characterization of RS-SiC materials was examined by means of SEM, TEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, process optimization methodology is also discussed. The flexural strength of RS-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

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무기 및 유기 박막을 포함하는 웨이퍼 적층 구조의 본딩 결합력 (Bond Strength of Wafer Stack Including Inorganic and Organic Thin Films)

  • 권용재;석종원
    • Korean Chemical Engineering Research
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    • 제46권3호
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    • pp.619-625
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    • 2008
  • 패시베이션 및 절연 목적으로 이용하는 플라즈마 화학기상증착(PECVD)법에 의해 증착된 무기막과 웨이퍼 간 본딩 접착제로 이용하는 유기 박막 적층면의, 열 순환에 의한 잔류 응력 및 본딩 결합력의 효과를 4점 굽힙 시험법과 웨이퍼 곡률 측정법에 의해 평가하였다. 무기막으로는 산화 규소막($SiO_2$)과 산화 질화막($SiN_x$)이, 유기 박막으로는 BCB(Benzocyclobutene)가 이용되었다. 이를 통해, 열 순환 동안 무기막과 유기막 사이에서의 잔류 응력과 본딩 결합력의 상관관계에 대한 모델식을 개발하였다. 최대 온도 350 및 $400^{\circ}C$에서 수행한 열 순환 공정에서, PECVD 산화 질화막과 BCB로 구성된 다층막에서, 본딩 결합력은 첫 번째 순환 공정 동안 감소한다. 이는 산화질화막 내 잔류인장응력의 증가가 다층막의 잔류응력에 의해 변형되는 에너지 및 본딩 결합력의 감소를 유도한다는 모델식의 예측과 일치하며, PECVD 산화 규소막내 잔류 압축 응력의 감소가 다층막의 잔류응력에 의해 변형되는 에너지 및 본딩 결합력 상승을 이끄는 산화 규소막과 BCB 구조의 본딩 결합력 결과와 비교된다. 이러한 산화 규소막과 산화 질화막을 포함한 다층막의 상반된 본딩 결합력은 증착 공정 후 막 내에 형성된 수소 결합이 고온 순환 공정 동안 축합 반응을 통해 더 밀집되어 인장응력을 형성하기 때문임을 알 수 있었다.

Effects of Mixing Ratio of Silicon Carbide Particles on the Etch Characteristics of Reaction-Bonded Silicon Carbide

  • Jung, Youn-Woong;Im, Hangjoon;Kim, Young-Ju;Park, Young-Sik;Song, Jun-Baek;Lee, Ju-Ho
    • 한국세라믹학회지
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    • 제53권3호
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    • pp.349-353
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    • 2016
  • We prepared a number of reaction-bonded silicon carbides (RBSCs) made from various mixing ratios of raw SiC particles, and investigated their microstructure and etch characteristics by Reactive Ion Etch (RIE). Increasing the amount of $9.5{\mu}m$-SiC particles results in a microstructure with relatively coarser Si regions. On the other hand, increasing that of $2.6{\mu}m$-SiC particles produces much finer Si regions. The addition of more than 50 wt% of $2.6{\mu}m$-SiC particles, however, causes the microstructure to become partially coarse. We also evaluated their etching behaviors in terms of surface roughness (Ra), density and weight changes, and microstructure development by employing Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM) techniques. During the etching process of the prepared samples, we confirmed that the residual Si region was rapidly removed and formed pits isolating SiC particles as islands. This leads to more intensified ion field on the SiC islands, and causes physical corrosion on them. Increased addition of $2.6{\mu}m$-SiC particles produces finer residual Si region, and thus decreases the surface roughness (Ra.) as well as causing weight loss after etching process by following the above etching mechanism.

CVD에 의한 고전력 디바이스용 단결정 3C-SiC 박막 성장 (Growth of Single Crystalline 3C-SiC Thin Films for High Power Devices by CVD)

  • 정귀상;심재철
    • 한국전기전자재료학회논문지
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    • 제23권2호
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    • pp.98-102
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    • 2010
  • This paper describes that single crystalline 3C-SiC (cubic silicon carbide) thin films have been deposited on carbonized Si(100) substrates using hexamethyldisilane (HMDS, $Si_2(CH_3){_6}$) as a safe organosilane single precursor and a nonflammable mixture of Ar and $H_2$ gas as the carrier gas by APCVD at $1280^{\circ}C$. The deposition was performed under various conditions to determine the optimized growth condition. The crystallinity of the 3C-SiC thin film was analyzed by XRD (X-ray diffraction). The surface morphology was also observed by AFM (atomic force microscopy) and voids between SiC and Si interfaces were measured by SEM (scanning electron microscopy). Finally, residual strain and hall mobility was investigated by surface profiler and hall measurement, respectively. From these results, the single crystalline 3C-SiC film had a good crystal quality without defects due to viods, a low residual stress, a very low roughness.

Fracture and Residual Stresses in $Metal/Al_2O_3-SiO_2$ System

  • 소대화
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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    • pp.308-312
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    • 2003
  • The packaging of the integrated circuits requires knowledge of ceramics and metals to accommodate the fabrication of modules that are used to construct subsystems and entire systems from extremely small components. Composite ceramics ($Al_2O_3-SiO_2$) were tested for substrates. A stress analysis was conducted for a linear work-hardening metal cylinder embedded in an infinite ceramic matrix. The bond between the metal and ceramic was established at high temperature and stresses developed during cooling to room temperature. The calculations showed that the stresses depend on the mismatch in thermal expansion, the elastic properties, and the yield strength and work hardening rate of the metal. Experimental measurements of the surface stresses have also been made on a $Cu/Al_2O_3-SiO_2$ ceramic system, using an indentation technique. A comparison revealed that the calculated stresses were appreciably larger than the measured surface stresses, indicating an important difference between the bulk and surface residual stresses. However, it was also shown that porosity in the metal could plastically expand and permit substantial dilatational relaxation of the residual stresses. Conversely it was noted that pore clusters were capable of initiating ductile rupture, by means of a plastic instability, in the presence of appreciable tri-axiality. The role of ceramics for packaging of microelectronics will continue to be extremely challenging.

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나노급 수소화된 비정질 실리콘층 두께에 따른 저온형성 니켈실리사이드의 물성 연구 (Property of Nickel Silicides with Hydrogenated Amorphous Silicon Thickness Prepared by Low Temperature Process)

  • 김종률;최용윤;박종성;송오성
    • 대한금속재료학회지
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    • 제46권11호
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    • pp.762-769
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    • 2008
  • Hydrogenated amorphous silicon(a-Si : H) layers, 120 nm and 50 nm in thickness, were deposited on 200 $nm-SiO_2$/single-Si substrates by inductively coupled plasma chemical vapor deposition(ICP-CVD). Subsequently, 30 nm-Ni layers were deposited by E-beam evaporation. Finally, 30 nm-Ni/120 nm a-Si : H/200 $nm-SiO_2$/single-Si and 30 nm-Ni/50 nm a-Si:H/200 $nm-SiO_2$/single-Si were prepared. The prepared samples were annealed by rapid thermal annealing(RTA) from $200^{\circ}C$ to $500^{\circ}C$ in $50^{\circ}C$ increments for 30 minute. A four-point tester, high resolution X-ray diffraction(HRXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and scanning probe microscopy(SPM) were used to examine the sheet resistance, phase transformation, in-plane microstructure, cross-sectional microstructure, and surface roughness, respectively. The nickel silicide on the 120 nm a-Si:H substrate showed high sheet resistance($470{\Omega}/{\Box}$) at T(temperature) < $450^{\circ}C$ and low sheet resistance ($70{\Omega}/{\Box}$) at T > $450^{\circ}C$. The high and low resistive regions contained ${\zeta}-Ni_2Si$ and NiSi, respectively. In case of microstructure showed mixed phase of nickel silicide and a-Si:H on the residual a-Si:H layer at T < $450^{\circ}C$ but no mixed phase and a residual a-Si:H layer at T > $450^{\circ}C$. The surface roughness matched the phase transformation according to the silicidation temperature. The nickel silicide on the 50 nm a-Si:H substrate had high sheet resistance(${\sim}1k{\Omega}/{\Box}$) at T < $400^{\circ}C$ and low sheet resistance ($100{\Omega}/{\Box}$) at T > $400^{\circ}C$. This was attributed to the formation of ${\delta}-Ni_2Si$ at T > $400^{\circ}C$ regardless of the siliciation temperature. An examination of the microstructure showed a region of nickel silicide at T < $400^{\circ}C$ that consisted of a mixed phase of nickel silicide and a-Si:H without a residual a-Si:H layer. The region at T > $400^{\circ}C$ showed crystalline nickel silicide without a mixed phase. The surface roughness remained constant regardless of the silicidation temperature. Our results suggest that a 50 nm a-Si:H nickel silicide layer is advantageous of the active layer of a thin film transistor(TFT) when applying a nano-thick layer with a constant sheet resistance, surface roughness, and ${\delta}-Ni_2Si$ temperatures > $400^{\circ}C$.