• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.313-314
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• 2012

본 연구는 반도체 배선형성에 있어 무전해 방식의 동(Electroless Copper) 피막특성에 관한 연구이다. 반도체 동 배선을 습식 무전해 도금공정을 이용하여 형성하였고, 이의 피막에 대하여 기본적인 표면 및 단면 조직이나 결정구조, 밀도, 석출속도, 밀착성 등을 분석하였다. 이어, 배선용 특성으로 요구되는 배선 비저항과 열처리에 따른 저항변화를 실험을 통하여 고찰하였고, 표면조도 및 조직구조에 따라 EM에 대한 영향성을 고찰하였다. 이어 AR3.0에 배선폭 30nm급의 초미세 배선상에서의 Gap-fill 상태를 확인한 결과 void없이 충진됨을 확인할 수 있었다.

• Journal of the Korean Vacuum Society
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• v.7 no.1
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• pp.11-16
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• 1998

In this study, we prepared a Na$_2$Se/NH$_4$OH solution to investigate a passivation effect of Se on GaAs surface. X-ray photoelectron spectroscopy and photoluminescence (PL) were used to analyse the surface chemical bonding states and the optical properties of GaAs after Se-treatment and a successive exposure to air, respcetively. It was observed that all of the observed selenium bound with arsenic to form As-Se bond and showed only one oxidation state as -2. PL intensity of Se-passivated surface was larger than that of HCI-cleaned surface, and this means that the effective reduction of surface state density of GaAs was successfully obtained by this treatment. However the existence of partial oxide on the Se-passivated surface was seemed to be a major cause to the degradation of Se passivation effcet. PL intensity of Se-passivated surface also decreased according to air-exposure and converged to that of HCI-cleaned surface.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.696-702
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• 2002

The BST $({Bal-xSrxTiO_3})$ (50/50) thin film has been grown by RF magnetron reactive sputtering and its characteristics such as crystallization, surface roughness, and electrical properties have been investigated with varying the film thickness. The crystallization and surface roughness of BST thin film are investigated by using XRD and AFM, respectively. The BST thin film annealed at $800^{\circ}C$ for 2 min has pure perovskite structure and good surface roughness of 16.1$\AA$. As the film thickness increases from 80 nm to 240 nm, the dielectric constant at 10 KHz increases from 199 to 265 and the leakage current density at 250 ㎸/cm decreases from $0.779 {\mu}A/{cm^2} to 0.184 {\mu}A/{cm^2}$. In the case of 240 nm-thick BST thin film, the charge storage density and leakage current density at 5V are 50.5 fC/${{\mu}m^2} and 0.182 {\mu}A/{cm^2}$, respectively. The values indicate that the BST thin film is a very useful dielectric material for the DRAM capacitor.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.1
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• pp.16-27
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• 2002

A level-set method is used for analyzing the behaviors of gas bubbles in two fluids incompressible viscous flow domain. The governing equations are solved by using a finite volume method. The numerical results are verified by comparing with the experimental and other computational results. Computations for the deformations and motions of one or multi-bubbles in the flow domain with the initial undisturbed free interface are conducted. It can be seen that numerical results for different surface tension and density ratio arise very different behaviors of bubbles. When bubbles rise near the free interface, the free interface gives some great influence on the behaviors of bubbles. The present results computed by a level-set method give useful information about the properties of bubble motions and deformations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.723-733
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• 2011

A numerical method of the CSF(Continuum Surface Force) model is presented for the calculation of the surface tension force and implemented in an in-house solution code(PowerCFD). The present method(code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with volume capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing. The application of the present method to a 2-D liquid drop problem is illustrated by an equilibrium and nonequilibrium oscillating drop calculation. It is found that the present method simulates efficiently and accurately surface tension-dominant multiphase flows.

• Journal of Conservation Science
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• v.28 no.1
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• pp.29-37
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• 2012

This study discusses a mercury amalgam gilding technique and examines how the color, surface and section of the gilt layer changes as the condition of heat treatment with mercury amalgam gilt object is changed. Some previous studies have mentioned reasons for various colors on gilt bronze artifacts depending on gilding manufacture and environment. However, reason for reddish color with gold on the artifacts' surface brought on high temperature corrosion has yet to be discussed and analyzed. A methodology was found in representing the mercury amalgam gilding technique and heat treatment test. According to the result of the heat treatment test, in the conditions of higher temperature and longer time, the oxidized layer on the gilt layer was distributed more widely and in the part when the oxide layer was eliminated, the gilt layer with a reddish color was observed. Moreover, in the surface observation of the specimen on which yellow and reddish colors were agitated, the changing aspects of its surface condition differed by colors. When investigated the section, it was observed that the void density and size became larger. After a test, the surface components changed; the temperature of heat treatment increased, component ratio of Hg and Au decreased gradually but component ratio of Cu increased. In regard to the gilt layer, as the time was longer and the temperature became higher for the heat treatment, the component ratio of Au and Cu by layers tended to change in inverse proportion. It is concluded that gilding techniques and the burial environment can make a difference in the surface color of the gilt layer on the gilt bronze artifacts, the high temperature corrosion that occurs by heat after they are manufactured is also one of the factors that affects their surface color.

• Electrical & Electronic Materials
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• v.8 no.4
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• pp.418-425
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• 1995

The surface of GaAs was treated by using the 0.1M solution of N $a_{2}$S.9 $H_{2}$O. The passivation of the surface in this sample was investigated by the photoreflectance(PR) experiment. The surface electric field( $E_{s}$) and built-in voltage( $V_{bi}$ ) discussed from Franz-Keldysh oscillation of PR signals. The density of surface states and Fermi level of GaAs treated with N $a_{2}$S.9 $H_{2}$O for 40min were determined 1.61*10$^{12}$ c $m^{-2}$ and 0.73eV. These values were about 15 and 10% smaller than those in untreated sample.e.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1320-1326
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• 1988

This paper deals with the behavior of surface crack growth and the characteristics of surface micro-crack distribution under creep and creep-fatigue with 1 min. and 10 min. of load holding times at 593.deg.C, in air. The test specimen is a plate type with a small artificial defect of type 304 the small defect has been carried out by the surface replica method and optical microphotography. The experimental results have been interpreted from the view-point of fracture mechanics. It can be concluded that the longer the hold time the longer the total life time. Most of surface micro-cracks initiate at grain boundaries before the specimen reaches 20% of its total life time, a few of them lead to fracture by coalescence with the main crack.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.378-381
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• 2008

고효율 a-Si:H/c-Si 이종접합 태양전지를 얻기 위해서는 우수한 c-Si wafer 위에 고품질의 비정질 실리콘박막을 통한 heterointerface를 형성하는 것이 매우 중요하다. 이를 달성하기 위해서는 공정중에 오염되기 쉬운 Si wafer 표면 상태를 정확히 검사하고 잘 관리하여야 한다. 본 연구에서는 세정 및 표면산화에 따른 Si wafer 상태를 Spectroscopic Ellipsometry 및 u-PCD를 이용하여 분석하였으며, <$\varepsilon$2> @4.25eV 값이 Si wafer 상태를 잘 나타내고 있음을 확인하였고 세정 최적화 할 경우 그 값이 43.02에 도달하였다. 또한 RF-PECVD로 증착된a-Si:H 박막을 EMA 모델링을 통해 분석한 결과 낮은 결정성과 높은 밀도를 가지는 a-Si:H를 얻을 수 있었으며, 이를 이종접합 태양전지에 적용한 결과 Flat wafer상에서 10.88%, textured wafer 적용하여 13.23%의 변환효율을 얻었다. 결론적으로 Spectroscopic Ellipsometry가 매우 얇고 고품질의 다층 박막이 필요한 이종접합 태양전지 분석에 있어 매우 유용한 방법임이 확인되었다.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.118-118
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• 1999

CVD방법에 의한 TiN 박막 형성에 있어서 ICP-CVD 방법이 대두되고 있다. 이것은 precursor에 대한 radical 형성, 식각된 패턴에서 양 벽의 self-shadowing 효과, 낮은 tress등으로 dense 한 박막을 얻을 수 있기 때문이다. TiN 박막은 Si 기판의 온도를 상온에서 50$0^{\circ}C$까지 유지하면서 TEMAT의 유량을 5-20sccm으로 변화시키면서 증착하였다. 증착 후 TiN 박막의 결정화에 따른 열처리는 Ar과 N2-가스분위기에서 in-situ로 증착하였다. 증착 후 TiN 박막증착 조건수립에 따른 플라즈마 특성진단은 전자의 온도와 밀도, 평균 전자밀도, 이온 에너지 분포, radical 분포, negative 이온분포 등으로 측정하였다. 플라즈마 변수에 따른 TiN 박막의 결정성과 상 변화는 XRD로 분석하였고, 조성비 및 TiN 박막의 원소화학적 상태, 결합에너지, 각 상에 따른 결합 에너지 천이정도, 초기 형성과정 및 반응기구 등은 RBS와 XPS로 조사하였다. TiN 박막의 표면상태, morphology 거칠기, TiN/Si(100)구조에서 계면상태 등은 SEM, AFM, 그리고 HRTEM으로 분석하였다. TiN 구조 박막의 비저항, carrier concentration 그리고 mobility 측정은 박막의 표면이 균일하고 bls-홀이 없는 것으로 하여 4-point probe 방법으로 측정하였다. 이들 분석으로부터 ICP-CVD 방법에 의하여 형성된 TiN 박막이 초고집적 반도체 소자의 contact barrier layer로서의 적용 가능성을 평가하였다.