• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.340-340
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• 2012

최근 MOS 소자들이 게이트 산화막을 Mono-layer가 아닌 Multi-Layer을 사용하는 추세이다. Bulk와 High-k물질간의 Dangling Bond를 줄이기 위해 Passivation 층을 만드는 것을 예로 들 수 있다. 이러한 Double Layer의 쓰임이 많아지면서 계면에서의 Interface State Density의 영향도 커지게 되면서 이를 측정하는 방법에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 $SiO_2$ Double Layer의 Interface State Density를 Conductance Method를 사용하여 구하는 연구를 진행하였다. Wet Oxidation과 Chemical Vapor Deposition (CVD) 공정을 이용하여 $SiO_2$ Double-layer로 증착한 후 Aluminium을 전극으로 하는 MOS-Cap 구조를 만들었다. 마지막 공정은 $450^{\circ}C$에서 30분 동안 Forming-Gas Annealing (FGA) 공정을 진행하였다. LCR meter를 이용하여 high frequency C-V를 측정한 후 North Carolina State University California Virtual Campus (NCSU CVC) 프로그램을 이용하여 Flatband Voltage를 구한 후에 Conductance Method를 측정하여 Dit를 측정하였다. 본 연구 결과 Double layer (Wet/CVD $SiO_2$)에 대해서 Conductance Method를 방법을 이용하여 Dit를 측정하는 것이 유효하다는 것을 확인 할 수 있었다. 본 실험은 앞으로 많이 쓰이고 측정될 Double layer (Wet/CVD $SiO_2$)에 대한 Interface State Density의 측정과 분석에 대한 방향을 제시하는데 도움이 될 것이라 판단된다.

• 한국세라믹학회지
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• 제35권11호
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• pp.1190-1196
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• 1998

Ultrafine ${\beta}$-SiC powders were synthesized by the vapor phase reaction of TMS[Si(CH3)4] in hydrogen The reaction temperature and TMS concentration were varied from 1000 to 1400$^{\circ}C$ and from 1 to 10% respectively. The average particle size and phase of the powders were analyzed by TEM and XRD. Ultrafine ${\beta}$-SiC powders were synthesized above 1000$^{\circ}C$ and the crystallinity of the powders increased with increasing reaction temperature. Shape of the particles were spherical and had average size of about 20 nm which showed no difference as the reaction temperature and TMS concentration increased. From the FT-IR analysis the absorption bands of Si-C of the powders shifted to higher wavenumber as the reaction temperature increased,. Under the condition of total gas flow above 1500cc/min ${\beta}$-SiC and poly-Si powders were obtained simultaneously. The Si-O bond intensity was increased under the condition of total gas flow rate above 1000cc/min which might be due to oxidation formed on poly-Si.

• 한국진공학회지
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• 제10권2호
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• pp.182-188
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• 2001

폴리카보네이트 시트의 내마모성을 향상시키기 위하여 HMDSO 모노머와 산소를 사용하여 플라즈마 기상증착시킨 $SiO_xC_y$ 필름의 특성을 분석하였다. RF출력, 산소투입량, 수소투입량을 변화시키면서 각 증착조건에 따른 생성된 필름의 화학결합구조, 원소조성, 표면조도, 헤이즈 특성에 미치는 영향을 FTIR, XPS, AFM, Hazemeter를 이용하여 알아보았다. HMDSO와 산소를 사용한 박막의 증착은 100 nm/min이상의 높은 증착속도를 가졌고,증착실험에서 얻은 증착필름의 원소조성을 XPS를 이용하여 구한 결과, 종전의 다른 유기실리콘계 모노머를 사용했을때보다 박막에 존재하는 탄소잔류물을 효과적으로 감소시키는 것을 확인하였다. 또한, RF출력 200 Watt에서 산소가 100 sccm투입되었을 때 가장 우수한 헤이즈 특성을 보이는 막을 얻을 수 있었다. 본 연구로부터 HMDSO/$O_2$시스템이 탄소함량이 낮은 박막을 형성시키고 내마모도가 좋은 박막을 증착시키는데 효과적인 것을 알 수 있었다.

• 한국세라믹학회지
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• 제17권2호
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• pp.61-68
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• 1980

The effect of the addition of various fluoreides on the mullitization of Korean crude kaolin was studied by X-ray powder diffraction and scanning electron microscopic methods. Kaolin without any addition of fluoreides began to be transformed into the mullite at 1, 10$0^{\circ}C$. Mullite peaks were discernible in the X-ray diffraction patterns of the specimens which contained fluorides equivalent to about 2 wt % fluorine, and which were sintered at 1, 05$0^{\circ}C$. The higher the concentration of fluorine in kaolin, the lower was the initiatinig temperature of mullitization. Experiments , for example, showed that mullite could be formed at 95$0^{\circ}C$ from kaolin mixed with 3.4% fluorine. Of the fluoride, addtives, sodiumsiliconfluoride $(Na_2SiF_6)$ was must effective in mullite formation of kaolin. In order of accelerating mullitization, the fluorides except $Na_2SiF_6$ could be placed in following sequence ; (1) sodium (NaF) (2) aluminium$(AlF_3)$ (3)potassium(KF) (4) ammonium$(NH_4F)$ (5) magnesium$(MgF_2)$ (6) calcium$(CaF_2)$. It was considered that the intrinsic characteristics of fluorides, such as size of ionic radiu, charge , bond strength between cation and anion, and electronegativity of cation affected millitization of halloysite, a main constituent mineral of kaolin.

• 대한금속재료학회지
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• 제47권11호
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• pp.748-753
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• 2009

The surface morphology and the surface roughness of n-type SiC induced by wet-treatment using 45% KOH and buffered oxide etchant (BOE-1HF : $6H_2O$) were investigated by atomic force microscopy (AFM). While Si-face of SiC could be etched by alkali solutions such as KOH, acidic solutions such as BOE were hardly able to etch SiC. When the rough SiC samples were used, the surface roughness of etched sample was decreased after wet-treatment regardless of etchant, due to the planarization the of surface by widening of scratches formed by mechanical polishing. It was observed that the initial etching was affected by the energetically unstable sites, such as dangling bond and steps. However, when a relatively smooth sample was used, the surface roughness was rapidly increased after treatment at $180^{\circ}C$ for 1 hr and at room temperature for 4 hr by using KOH solution, resulting from the nano-sized structures such as pores and bumps. This indicates that porous SiC surface can be achieved by using purely chemical treatment.

• 한국세라믹학회지
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• 제20권1호
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• pp.63-69
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• 1983

It is know that $Si_3-N_4$ bonded SiC has almost all the valuable properties needed for the high temperature material and thus has bery wide range of applicability. Si powder and two different sized SiC powder were used as the raw mateials. Specimens were prepared by heating the green compact mode of the raw materials with polyvinyl alcohol binder in the nitrogen atmosphere. The bond-ing of SiC particles is brought about with the formation of reaction bonded silicon nitride phase between the particles he influences of the variation of the relative amounts of the raw materials and the amount of the organic binder on the density and the bend strength of the specimens were investigated. It was shown that the calculation of the amount of the nitridation of Si is somewhat complicated matter since some portion of the organic binder reacts with the Si during the firing process. Fixing the Si amount to 20w/o the distributions of the size of the SiC particles that gives the maximum density and the maximum strnegth were obtained through experiments. It was observed that the two distributions were not equal to each other. As the amount of Si increased the amount of Si reacted with nitrogen and the strength increased. The fracture mode was intergranular for the most part and the transgranular fracture was scarcely observed.

• 한국세라믹학회지
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• 제44권7호
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• pp.393-402
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• 2007

Polyaluminocarbosilane was synthesized by direct reaction of polydimethylsilane with aluminum(III)-acetylacetonate in the presence of zeolite catalyst. A fraction of higher molecular weight polycarbosilane was formed due to the binding of aluminium acetylacetonate radicals with the polycarbosilane backbone. Small amount of Si-O-Si bond was observed in the as-prepared polyaluminocarbosilane as the result. Polyaluminocarbosilane fiber was obtained through a melt spinning and was pyrolyzed and sintered into SiC fiber from $1200{\sim}2000^{\circ}C$ under a controlled atmosphere. The nucleation and growth of ${\beta}-SiC$ grains between $1400{\sim}1600^{\circ}C$ are accompanied with nano pores formation and residual carbon generation. Above $1800^{\circ}C$, SiC fiber could be sintered to give a fully crystallized ${\beta}-SiC$ with some ${\alpha}-SiC$.

• 대한전자공학회논문지
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• 제26권7호
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• pp.73-82
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• 1989

실리콘계 절연박막 형성을 위한 저온공정을 개발하기 위하여 photo-CVD장치를 제작하여 $SiO_2$ 박막을 $50{\sim}250^{\circ}C$ 범위에서 증착시켰다. 이때 $SiH_4/N_2O$ 혼합가스는 수은증감반응법을 사용하지 않고 저압수은램프의 직접 광여기에 의해 분해시켰다. AES와 ESCA 분석결과 Si와 O의 화학량론적 구성이 거의 모든 공정조건에서 1:2로 나타났고, Si와 O원자의 결합상태가 $SiO_2$의 형태로 이루어져 있음을 보여주었다. 그리고 박막의 굴절율은 $1.39{\sim}1.44$의 범위로 나타나, 저온증착에 의해 밀도가 비교적 낮은 박막이 형성됨을 보였다.

• 한국결정성장학회지
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• 제24권1호
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• pp.41-45
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• 2014

다양한 공정 조건으로 $SiN_x$와 $SiO_2$ 박막을 형성하고 이에 대한 패시베이션 특성에 대한 연구를 수행하였다. Plasma enhanced chemical vapor deposition(PECVD)을 이용하여 증착된 $SiN_x$ 박막의 경우, 증착 두께가 증가함에 따라 페시베이션 특성이 향상되는 것을 관찰하였다. 이는 PECVD 증착 공정 중 유입되는 수소 원자들이 실리콘 표면에 존재하는 Dangling bond와 결합하여 소수 캐리어의 재결합 현상을 효과적으로 감소시켰기 때문이다. 건식 산화법으로 형성된 $SiO_2$ 박막은 습식 산화법으로 형성된 것 보다 치밀한 계면 구조를 가짐으로 인하여 약 20배 이상 우수한 패시베이션 특성을 나타내었다. 건식 산화 공정 온도가 증가함에 따라 패시베이션 특성이 열화되는 현상이 발생하였고, Capacitance-voltage(C-V) 및 Conductance-voltage(G-V) 분석을 통하여 $SiO_2$/실리콘 계면에 존재하는 계면 결함 밀도 증가에 의해 나타나는 현상임을 알 수 있었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권5호
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• pp.185-190
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• 2002

Capacitor material utilized in the downsizing passive devices and dynamic random access memory(DRAM) requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. Common capacitor materials, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$,TaN and et al., used until recently have reached their physical limits in their application to several hundred angstrom scale capacitor. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25 ~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism, design and fabrication for $Ta_2O_{5}$ film capacitor. This study presents the structure-property relationship of reactive-sputtered $Ta_2O_{5}$ MIM capacitor structure processed by annealing in a vacuum. X-ray diffraction patterns skewed the existence of amorphous phase in as-deposited condition and the formation of preferentially oriented-$Ta_2O_{5}$ in 670, $700^{\circ}C$ annealing. On 670, $700^{\circ}C$ annealing under the vacuum, the leakage current decrease and the enhanced temperature-capacitance characteristic stability. and the leakage current behavior is stable irrespective of applied electric field. The results states that keeping $Ta_2O_{5}$ annealed at vacuum gives rise to improvement of electrical characteristics in the capacitor by reducing oxygen-vacancy and the broken bond between Ta and O.