• 한국세라믹학회지
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• 제31권12호
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• pp.1588-1598
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• 1994

The SiC/MoSi2 composite materials were fabricated by infiltrating the mixture of molybdenum disilicide and metal silicon(MoSi2+Si=100) to a porous compact of silicon carbide and graphite under the vacuum atmosphere of 10-1 torr. The specimen were oxidized in dry air under 1 atm at 130$0^{\circ}C$~150$0^{\circ}C$ for 240 hours. The oxidation behavior was evaluated by the weight gain and loss per unit area of the oxidized samples. Also, SEM and XRD analysis of the oxidized surface of the samples were carried out. With increasing the MoSi2 content and oxidation temperature, the passive oxidation was found. The trend of weight gain of all samples was followed the parabolic rate law with the formation of a protective layer of cristobalite on the surface.

• 대한전자공학회논문지
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• 제25권11호
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• pp.1304-1314
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• 1988

Porous실리콘 形成反應에서 HF濃度, 電流應度, 反應時間 및 基叛의 表面狀態가 PSL (Porous Silicon Layers)의 porosity에 미치는 影響을 실험적으로 조사하였다. PSL을 陽배化 시켜서 室溫에서 FIPPOS-SOI를 제조하는 방법을 연구하였다. 이 방법으로 100um폭의 SOI strip line을 제조하였으며 SOI의 stress제거를 위해 2단계 PSL 형성법을 이용하였다. 또한 이 실온 SOI 제조기술을 이용하여 이미 소자공정을 끝낸 집적회로를 SOI화 시킬 수 있는 방법을 제안하였다.

• 대한전기학회논문지
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• 제45권1호
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• pp.93-99
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• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• 한국표면공학회지
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• 제22권4호
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• pp.215-220
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• 1989

Silicon Nitride whose thickness is about $100\AA$by the ellipsometer was successfully formed by the Plasma reaction. Nitrogen Plasma was formed by applying the 200KHz, 500Watt power between the two electroes and nitridation of silicon was carried out directly on the top of the silicon wafer. Thus Silicon Nitride formed was oxidized to from oxynitrides and their electrical characterlstice were analyzed by measuring I-V curves and capacitances. Through ESCA depth profiles, the chemical composition changes before and after the oxidation wers analyzed.

• 한국주조공학회지
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• 제29권6호
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• pp.257-264
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• 2009

The effects of silicon and molybdenum on the temperature-dependent properties of high silicon and high molybdenum ductile cast iron were investigated. Microstructure was composed of ferrite, cell boundary complex carbide, carbide precipitated in the grain and graphite. The number and size of carbide decreased with the increase of silicon content and increased with the increase of molybdenum content, however, the size of cell boundary carbide increased above 0.81wt%Mo. The room temperature tensile strength increased with the increase of silicon and molybdenum contents. That did not increase with the latter with more than 0.8wt%. Meanwhile the high temperature tensile strength showed the similar trend to that of room temperature one, that of the specimen with 0.55wt%Mo was the highest. The $A_1$ transformation temperature increased with the silicon and molybdenum contents, and showed similar tendency with the variation of strength. It was discussed due to the solubility limit of Molybdenum in ferrite, of which value was assumed to be in the vicinity of 0.81wt%Mo. The weight after oxidation at 1,173K showed the result caused by the difference in solubility of molybdenum in the matrix. That and the thickness change after oxidation did not show any consistent trend with the silicon and molybdenum contents.

• 대한전자공학회논문지
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• 제26권4호
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• pp.67-72
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• 1989

부분산화공정(LOCOS : local oxidation of silicon)에서 발생하는 새부리의 길이를 줄이기 위하여 상온 플라즈마 질화막을 잉요한 시로운 공정에 대해 연구하였다. 400W, 100kHz의 교류 전력에 의한 질소 플라즈마로 실리콘 위에 두께가 $100{\AA}$ 미만의 균일한 실리콘 질화막을 형성시킬 수 있었다. 이렇게 형성된 질화막은 실리콘을 4000${\AA}$두께로 산화시키는 공정에서 실리콘의 산화를 효과적으로 방지할 수 있었고 새부리의 길이를 0.2${mu}m$로 감소시킬 수 있다는 것을 SEM 단면도로 확인하였다. 이 길이는 두꺼운 LPCVD 질화막을 이용한 기존의 부분산화공정에서의 0.7${mu}m$ 보다 훨씬 줄어든 것이다. Secco에칭 후 SCM으로 단면을 보았을때 새부리 근처에서 결정 결함을 관찰할 수 없었다. 이 새로운 LOCOS공정으로 $N^+/P^-\;well,\;P^+/N^-$ well 다이오드를 만들어 누설전류를 측정하였다. 그 결과 기존의 LOCOS 공정에 의한 성질보다 우수하거나 동등한 성질을 나타내었다.

• Carbon letters
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• 제12권2호
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• pp.116-119
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• 2011

C/SiC composites were prepared by boron nitride (BN)-assisted liquid silicon infiltration (LSI), and their anti-oxidation and mechanical properties were investigated. The microstructures, bulk densities, and porosities of the C/SiC composites demonstrated that the infiltration of liquid silicon into the composites improved them, because the layered-structure BN worked as a lubricant. Increasing the amount of BN improved the anti-oxidation of the prepared C/SiC composites. This synergistic effect was induced by the assistance of BN in the LSI. More thermally stable SiC was formed in the composite, and fewer pores were formed in the composite, which reduced inward oxygen diffusion. The mechanical strength of the composite increased up to the addition of 3% BN and decreased thereafter due to increased brittleness from the presence of more SiC in the composite. Based on the anti-oxidation and mechanical properties of the prepared composites, we concluded that improved anti-oxidation of C/SiC composites can be achieved through BN-assisted LSI, although there may be some degradation of the mechanical properties. The desired anti-oxidation and mechanical properties of the composite can be achieved by optimizing the BN-assisted LSI conditions.

• 한국재료학회지
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• 제4권6호
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• pp.662-668
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• 1994

실리콘 질화막을 습식 산화하여 제작한 산화막/질화막 복합층과 이 박막의 산화막을 식각하여 제작한 oxynitride 박막의 물리적, 전기적 특성을 기술하였다. $900^{\circ}C$에서 산화시간이 증가함에 따라 산화막/질화막의 경우에는 축전용량은 급격히 감소하였으나 절연 파괴전장은 증가하였다. Oxynitrite박막은 축전용량과 절연파괴 전장이 모두 증가하였다. Oxynitride박막의 경우 축전 용량의 증가와 절연 파괴 전장이 증가하였는데 이는 유효 주께 감소와 박막의 양질화에 기인하였다. 또한, 산화 시강의 증가에 따라 Oxynitride박막의 TDDB특성과 초기 불량율도 향상되었다. 결론적으로 Oxynitride박막은 dynamic기억소자의 유전체 박막으로 사용하기에 적합하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.30.1-30.1
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• 2011

Silicon is one of useful materials in various industry such as semiconductor, solar cell, and secondary battery. The metallic silicon produces generally melting process for ingot type or chemical vapor deposition (CVD) for thin film type. However, these methods have disadvantages of high cost, complicated process, and consumption of much energy. Electrodeposition has been known as a powerful synthesis method for obtaining metallic species by relatively simple operation with current and voltage control. Unfortunately, the electrodeposition of the silicon is impossible in aqueous electrolyte solution due to its low oxidation-reduction equilibrium potential. Ionic liquids are simply defined as ionic melts with a melting point below $100^{\circ}C$. Characteristics of the ionic liquids are high ionic conductivities, low vapour pressures, chemical stability, and wide electrochemical windows. The ionic liquids enable the electrochemically active elements, such as silicon, titanium, and aluminum, to be reduced to their metallic states without vigorous hydrogen gas evolution. In this study, the electrodeposion of silicon has been investigated in ionic liquid of 1-butyl-3-methylpyrolidinium bis (trifluoromethylsulfonyl) imide ([bmpy]$Tf_2N$) saturated with $SiCl_4$ at room temperature. Also, the effect of electrode materials on the electrodeposition and morphological characteristics of the silicon electrodeposited were analyzed The silicon electrodeposited on gold substrate was composed of the metallic Si with single crystalline size between 100~200nm. The silicon content by XPS analysis was detected in 31.3 wt% and the others were oxygen, gold, and carbon. The oxygen was detected much in edge area of th electrode due to $SiO_2$ from a partial oxidation of the metallic Si.

• 분석과학
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• 제5권4호
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• pp.359-366
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• 1992

본 논문은 마이크로 Raman 분광분석법을 이용하여 국부적 열산화 후 실리콘 표면에 유입되는 스트레스를 평가한 것이다. 국부적 열산화 후 실리콘 표면에 유입되는 스트레스는 실리콘 산화막과 active 영역의 경계 부분에서 최대치를 나타내었다. Active 영역의 크기가 작아질수록 스트레스량은 증가하며, 이는 스트레스가 active 영역의 크기에 의존함을 보여 주는 것이다. 또한, active 영역이 $0.45{\mu}m$인 세 가지 소자 분리 공정, A, B, moB를 평가한 결과 moB 공정의 스트레스 값이 가장 작았으며, 새부리 효과도 가장 작았다.