• 청정기술
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• 제23권4호
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• pp.357-363
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• 2017

본 연구에서는 초임계 이산화탄소/n-butyl acetate ($scCO_2$/n-BA) 공용매를 사용하여 네거티브형 포토레지스트(PR)를 제거하는 실험을 진행하였다. $scCO_2$와 n-BA의 용해도 평가를 통해 n-BA가 $scCO_2$와 균일하게 섞이는 조건을 실험적으로 측정하였다. 다양한 실험 변수를 조정하여 포토레지스트 제거 실험을 진행하였고, 미노광 포토레지스트 제거에 대한 최적의 조건을 확립하였다. 또한, 노광된 PR과 미노광 PR의 제거율을 비교하여 $scCO_2$/n-BA 공용매의 선택적 제거 성능을 확인하였다. 노광된 PR은 $scCO_2$/n-BA 공용매 환경에서 매우 안정적으로 존재함을 관찰하였고, 미노광 PR은 160 bar, $40^{\circ}C$, 75 wt% n-BA 이상의 농도에서 완전히 제거됨을 확인하였다. $scCO_2$/n-BA 공용매 시스템은 노광 PR과 미노광 PR 사이의 높은 선택성을 제공할 수 있으며, 네거티브 PR의 리소그래피 공정에서 높은 신뢰성을 부여할 것으로 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.76.2-76.2
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• 2010

질산 용액을 이용한 처리를 통해서 실리콘 웨이퍼 위에 누설 전류가 thermal oxidation 방법과 비슷한 수준의 얇은 실리콘 산화막을 형성할 수 있다. 이러한 처리 방법은 thermal oxidation에 비해서 낮은 온도에서 공정이 가능하다는 장점을 가진다. 이 때 질산 용액으로 68 wt% $HNO_3$을 쓰는데, 이 용액에만 넣었을 때에는 실리콘 산화막이 어느 정도 두께 이상은 성장하지 않는 단점이 있다. 그렇기 때문에 실리콘 웨이퍼를 68 wt% $HNO_3$에 넣기 전에 seed layer 산화막을 형성 시킨다. 본 연구에서는 p-type 웨이퍼를 phosphorus로 도핑해서 에미터를 형성 시킨 후에 seed layer를 형성 시키고 68 wt% $HNO_3$를 이용해서 에미터 위의 실리콘 산화막을 성장 시켰다. 이 때 보다 더 효과적인 seed layer를 형성 시키는 용액을 찾아서 실험하였다. 40 wt% $HNO_3$, $H_2SO_4-H_2O_2$, HCl-$H_2O_2$ 용액에 웨이퍼를 10분 동안 담그는 것을 통해서 seed layer를 형성하고, 이를 $121^{\circ}C$인 68 wt% $HNO_3$에 넣어서 실리콘 산화막을 성장시켰다. 이렇게 형성된 실리콘 산화막의 특성은 엘립소미터, I-V 측정 장치, QSSPC를 통해서 알아보았다.

• Computers and Concrete
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• 제20권2호
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• pp.119-127
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• 2017

Time-dependent buckling of embedded straight concrete columns armed with Silicon dioxide($SiO_2$) nano-particles exposed to fire is investigated in the present study for the fire time. The column is simulated mathematically with Timoshenko beam model. The governing mass conservation equations to describe heat and moisture transport in concrete containing free water, water vapor, and dry air in conjunction with the conversion of energy are considered. The characteristics of the equivalent composite are determined using Mori-Tanaka approach. The foundation around the column is simulated with spring and shear layer. Employing nonlinear strains-displacements, energy methods and Hamilton's principal, the governing equations are derived. Differential quadrature method (DQM) is used in order to obtain the critical buckling load and critical buckling time of structure. The influences of volume percent of $SiO_2nano-particles$, geometrical parameters, elastic foundation and concrete porosity are investigated on the time-dependent buckling behaviours of structure. Numerical results indicate that reinforcing the concrete column with $SiO_2nano-particles$, the structure becomes stiffer and the critical buckling load and time increase.

• 센서학회지
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• 제27권3호
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• pp.170-174
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• 2018

In this paper, the $TiO_2$/glucose oxidase (GOD) mixture has synthesized through simple and low-cost fabrication methods. The physical properties of the mixture were proved using an FT-IR/NIR spectrometer, an X-Ray diffractometer, and a Raman spectrometer. GOD maintained its bioactivity during all fabrication process. The current characteristics of the glucose biosensor were proportional to the glucose concentration and effective surface area of square pyramid on a silicon substrate. The maximum current change was measured in a pH 7.0 buffer solution. The simple and low-cost fabrication process and surface treatment can be used widely in previous research for improvements in effective surface area.

• 한국정보통신학회논문지
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• 제7권2호
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• pp.250-254
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• 2003

본 논문에서는 2GHz 대역 RF 대역통과 필터 응용을 위한 FBAR 소자에 대한 연구를 발표한다. 본 연구의 FBAR 소자는 크게 상부 및 하부 전극 사이에 압전체(AlN)가 삽입되어 있는 공진부와 SiO2/W이 여러층으로 적층되어 있는 음향반사층 두 부분으로 구성되어 있다. RF sputtering 방법으로 증착된 AlN 박막은 c축이 기판에 수직한 정도가 우수한 c축 우선 배향성을 갖는다. 이때 결정립(grain)은 길고 얇은 주상형(columnar)을 보인다. 뿐만아니라, 우수한 품질계수(4300)와 반사손실(37.19 dB)도 얻어졌다.

• 한국제4기학회지
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• 제17권2호
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• pp.1-7
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• 2003

Environmental changes caused by the abrupt climatic change are one of the important issues in the scientific community. In the East Sea, abrupt climatic shift, called Younger Dryas, is identified. The age of the Younger Dryas cold episode occurred at 11.2 ka. Overall, changes in circulation and bottom water conditions occurred during the Younger Dryas cold episode in the study area. Especially, climatic transition from meltwater spike to the Younger Dryas cold episode is characterized by significant shifts of oxygen isotope values, the coiling ratios of Neogloboquadrina pachyderma, and the planktonic foraminifers abundances. The impact of abrupt climate change on the ecosystem is very significant. In the East Sea, the calcium carbonate secreting organism(foraminifers) is replaced by silicon dioxide secreting organisms(diatom, radiolarian) after the abrupt and severe cold climatic event. Based on the Doctrine of Uniformitarianism, at least climate change for the next 100 years would be severely influence on the marine ecosystem.

• 한국대기환경학회지
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• 제27권3호
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• pp.326-336
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• 2011

The Light Detection and Ranging (Lidar) observation provides a specific knowledge of the temporal and vertical distribution and the optical properties of the aerosols. Unlike typical Mie scattering Lidars, which can measure backscattering and depolarization, the Raman Lidar can measure the quartz signal at the ultra violet (360 nm) and the visible (546 nm) wavelengths. In this work, we developed a method for estimating mineral quartz concentration immersed in Asian dust using Raman scattering of quartz (silicon dioxide, silica). During the Asian dust period of March 15, 16, and 21 in 2010, Raman lidar measurements detected the presence of quartz, and successfully showed the vertical profile of the dust concentrations. The satellite observations such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) confirmed spatial distribution of Asian dust. This approach will be useful for characterizing the quartz dominated in the atmospheric aerosols and the investigations of mineral dust. It will be especially applicable for distinguishing the dust and non-dust aerosols in studies on the mixing state of Asian aerosols. Additionally, the presented method combined with satellite observations is enable qualitative and quantitative monitoring for Asian dust.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.707-710
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• 2004

Chemical mechanical polishing (CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of in the defect-free inter-level dielectrics (ILD). In this paper, we have investigated slurry properties and CMP performance of silicon dioxide (oxide) as a function of different temperature of slurry. Thermal effects on the silica slurry properties such as pH, particle size, conductivity and zeta potential were studied. Moreover, the relationship between the removal rate (RR) with WIWNU and slurry properties caused by changes of temperature were investigated. Therefore, the understanding of these temperature effects provides a foundation to optimize an oxide CMP Process for ULSI multi-level interconnection technology.

• Carbon letters
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• 제15권3호
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• pp.192-197
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• 2014

A hierarchical pore structured novolac-type phenol based-activated carbon with micropores and mesopores was fabricated. Physical activation using a sacrificial silicon dioxide ($SiO_2$) template and chemical activation using potassium hydroxide (KOH) were employed to prepare these materials. The morphology of the well-developed pore structure was characterized using field-emission scanning electron microscopy. The novolac-type phenol-based activated carbon retained hierarchical pores (micropores and mesopores); it exhibited high Brunauer-Emmett-Teller specific surface areas and hierarchical pore size distributions. The hierarchical pore novolac-type phenol-based activated carbon was used as an electrode in electric double-layer capacitors, and the specific capacitance and the retained capacitance ratio were measured. The specific capacitances and the retained capacitance ratio were enhanced, depending on the $SiO_2$ concentration in the material. This result is attributed to the hierarchical pore structure of the novolac-type phenol-based activated carbon.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권3호
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• pp.158-166
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• 2001

Based on uniform hot carrier injection (optically assisted electron injection) across the $Si-SiO_2$ interface into the gate insulator of n-channel IGFETs, the threshold voltage shifts associated with electron injection of $1.25{\times}l0^{16}{\;}e/\textrm{cm}^2 between 0.5 and 7 MV/cm were found to decrease from positive to negative values, indicating both a decrease in trap cross section ($E_{ox}{\geq}1.5 MV/cm$) and the generation of FPC $E_{ox}{\geq}5{\;}MV/cm$). It was also found that FNC and large cross section NETs were generated for $E_{ox}{\geq}5{\;}MV/cm$. Continuous, uniform low-field (1MV/cm) electron injection up to $l0^{19}{\;}e/\textrm{cm}^2 is accompanied by a monatomic increase in threshold voltage. It was found that the data could be modeled more effectively by assuming that most of the threshold voltage shift could be ascribed to generated bulk defects which are generated and filled, or more likely, generated in a charged state. The injection method and conditions used in terms of injection fluence, injection density, and temperature, can have a dramatic impact on what is measured, and may have important implications on accelerated lifetime measurements.