• 공업화학
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• 제8권5호
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• pp.830-836
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• 1997

본 실험에서는 물유리를 사용하여 산세척에 의하여 제조된 산화철 입자의 표면개질에 대하여 연구하였다. 사용한 물유리의 $SiO_2$와 $Na_2O$의 몰비($SiO_2/Na_2O$)는 1, 2, 3.5이였다. 첨가되는 실리카의 양과 pH에 따라 산화철 현탁액의 분산성을 입자의 표면하전과 침강속도에 의하여 평가하였다. 그리고, 중성 영역에서 산화철 입자의 분산안정성을 유지할 수 있는 표면개질제(실리카)의 양을 도출하였으며, 물유리에 의한 산화철 입자의 표면개질을 습식 볼밀링에 의하여 슬러리 상태에서 실시하였다. 그 결과, 표면처리한 산화철 현탁액의 분산 안정성은 실리카의 양과 pH에 상호 의존하였다. 미처리한 산화철은 등전점인 pH 8에서 분산안정성을 잃고 있었으나, 산화철에 대하여 약 0.8wt%의 실리카로 표면처리한 산화철은 pH 5 이상 중성영역에서 분산안정성을 나타내었으며, 음이온성 계면활성제를 0.2wt% 이상 첨가에 의한 분산안정성이 더욱 증가되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.204-208
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• 1991

In this paper, the radiation properties of a far-Infrared using a PTC thermistor, the $BaTiO_3$+1.63mol% $Al_2O_3$+3.75mol% $SiO_2$+1.25mol% $TiO_2$(1/3 $Al_2O_3+xSiO_2$+(1-x) $TiO_2$; total x: 6.67mol%) ceramics, in order to progress the grade resistivity characteristics, by adding an ethanol solution of $Mn(NO_3){\cdot}6H_2O$ was investigated. The ceramics was fabricated by wet-mill method. The sintering temperature read 1300-1350$[^{\circ}C]$ and the holding time was 3 hours. The quantity of $Sb_2O_3$ and $Al_2O_3$ for an activation of the far-infrared radiation in ceramics was doped. In sintering, R-T property was measured by varying the grade temperature. The anatase-lighting apparatus and microstructures by using XRD and SEM were observed. $Sb_2O_3$. oxides additive. affected the semiconducting and emissivity and MnO was devoted an increase of resistivity. The specimen which only $Sb_2O_3$ is added to was high appeared far-infrared emissivity and Mno was not affacted the far-infrared radiation. The ceramics shows that it is effective in the structure of the human bodies as organic bodies and can be applied as electron device.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.326-328
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• 1995

SiC buffer layers were grown on Si(100) substrates by ultra-high-vacuum electron cryclotron resonance plasma (UHV ECR plasma) from $CH_4/H_2$ mixture at 700$^{\circ}C$. The electron densities and temperature were measured by single probe. The axial plasma potentials measured by emissive probe had the double layer structure at positive substrate bias. Piranha cleaning was carried out as ex-situ wet cleaning. Clean and smooth silicon surface were prepared by in-situ hydrogen plasma cleaning at 540$^{\circ}C$. A short exposure to hydrogen plasma transforms the Si surface from 1$\times$1 to 2$\times$1 reconstruction. It was monitored by reflection high energy electron diffraction (RHEED). The defect densities were analysed by the dilute Schimmel etching. The results showed that the substrate bias is important factor in hydrogen plasma cleaning. The low base pressure ($5\times10^{-10}$ torr) restrains the $SiO_2$ growth on silicon surface. The grown layers showed different characteristics at various substrate bias. RHEED and K-ray Photoelectron spectroscopy study showed that grown layer was SiC.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.65-65
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• 1999

Dry etching technique provides more easy controllability on the etch profile such as anisotropic etching than wet etching process and the results of lots of researches on the characterization of various plasmas or ion beams for semiconductor etching have been reported. Chlorine-based plasmas or chlorine ion beam have been often used to etch several semiconductor materials, in particular Si-based materials. We have studied the effect of He flow rate on the Si and SiO2 dry etching using chlorine-based plasma. Experiments were performed using reactive ion etching system. RF power was 300W. Cl2 gas flow rate was fixed at 58.6 sccm, and the He flow rate was varied from 0 to 120 sccm. Fig. 1 presents the etch depth of si layer versus the etching time at various He flow rate. In case of low He flow rate, the etch rate was measured to be negligible for both Si and SiO2. As the He flow increases over 30% of the total inlet gas flow, the plasma state becomes stable and the etch rate starts to increase. In high Ge flow rate (over 60%), the relation between the etch depth and the time was observed to be nearly linear. Fig. 2 presents the variation of the etch rate depending on the He flow rate. The etch rate increases linearly with He flow rate. The results of this preliminary study show that Cl2/He mixture plasma is good candidate for the controllable si dry etching.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권3호
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• pp.199-205
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• 2006

Patterned sapphire substrates (PSS) were fabricated by a simple wet etching process with $SiO_2$ stripe masks and a mixed solution of $H_2SO_4$ and $H_3PO_4$. GaN layers were epitaxially grown on the PSS under the optimized 2-step growth condition of metalorganic vapor deposition. During the 1st growth step, GaN layers with triangular cross sections were grown on the selected area of the surface of the PSS, and in the 2nd growth step, the GaN layers were laterally grown and coalesced with neighboring GaN layers. The density of threading dislocations on the surface of the coalesced GaN layer was $2{\sim}4\;{\times}\;10^7\;cm^{-2}$ over the entire region. The epitaxial structure of near-UV light emitting diode (LED) was grown over the GaN layers on the PSS. The internal quantum efficiency and the extraction efficiency of the LED structure grown on the PSS were remarkably increased when compared to the conventional LED structure grown on the flat sapphire substrate. The reduction in TD density and the decrease in the number of times of total internal reflections of the light flux are mainly attributed due to high level of scattering on the PSS.

• 한국환경과학회지
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• 제32권6호
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• pp.477-482
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• 2023

Halloysite nanotube (HNT) has a nanotube structure with the chemical formula of Al₂Si₂O₅(OH)₄ · nH₂O and is a natural sediment of aluminosilicate. A lot of research has been conducted to improve the mechanical properties of epoxy composites by generating interactions between HNTs and polymers through surface treatment of HNTs, such as exchange of amine group as a terminal functional group. However, most of the surface modification methods are performed under wet conditions, which require a relatively large amount of time, manpower and solvent. In order to save time and simplify complicated procedures, a dry coating machine was designed and used for amine group exchange. Comparing the XPS results, it was found that the results of NH₂-HNT prepared using a dry coating machine and the substitution through the wet method were not significantly different, and it has been confirmed that the amount of solvent used and the time savings can be made.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.491-492
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• 2009

We have fabricated a microlens integrated silicon (Si) structure for optical interconnects. To form microlenses, the Si wafer was wet-etched with $SiN_x$ mask in a HF:$HNO_3:C_2H_4O_2$ solution and then the holes were filled with a AZ9260 photoresist. The focal length of microlens increased in proportional to its radius of curvature (ROC). For the ROC of $100-161{\mu}m$, the focal lengths were obtained approximately between $160{\mu}m$ and $310{\mu}m$, in an agreement with the simulated values using a ray tracing method.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.344-349
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• 2006

[ $60{\sim}70nm$ ] 급의 design rule을 가진 고집적 반도체 소자를 제작하려면, 트랜지스터 형성 이후의 공정에서 thermal budget을 줄이기 위하여 공정의 온도를 낮추는 것이 중요하다. 본 연구에서는 고온의 습식 산화막을 대체할 수 있는 저온의 LPCVD (Low-Pressure Chemical Vapor Deposition) $SiO_2$(LTO : Low-Temperature Oxide) 박막 증착공정을 제시하였으며, ONO (Oxide/Nitride/Oxide) 구조의 커패시터를 형성하여 증착된 LTO 박막의 전기적인 신뢰성을 평가하였다. LTO 박막은 5 MV/cm 이하의 전기장 영역에서는 고온의 습식 산화막과 크게 차이가 없는 누설전류 특성을 보였으나, 더 높은 전기장의 영역에서는 훨씬 더 우수함을 보여주었다.

• 한국산학기술학회논문지
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• 제6권3호
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• pp.273-277
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• 2005

새로이 제안된 15nm-Ni/15nm-Co의 적층구조로부터 제조된 NiCo 복합실리사이드를 실제 디바이스에 채용하기 위해, $SiO_2$ 스페이서를 가진 폴리실리콘 게이트 선폭이 $0.25\~l.5um$까지 변화하는 테스트그룹을 이용하여 30초-RTA를 이용한 실리사이드화 온도를 $700^{\circ}C\~1100^{\circ}C$까지 변화시키면서 이때 cleaning전후의 잔류금속의 생성모습을 확인하였다. RTA온도가 올라갈수록 $SiO_2$로 구성된 필드와 스페이서 상부와, 실리사이드가 형성된 게이트 상부에 $0.25{\mu}m$정도의 단축직경을 가진 타원형 잔류금속이 미로형 또는 게이트 방향으로 생성되는 특징이 있었고 동시에 응집이 많아지는 현상이 있었다. 응집이 많을수록 하부 절연층과의 반응도가 증가하여 절연특성이 저하될 수 있었고 과도한 습식제거 공정을 오래하여야 하므로 실험범위 내에서 가급적 저온 실리사이드화 열처리가 바람직하였다.

• 한국결정성장학회지
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• 제31권6호
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• pp.240-246
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• 2021

도자 생산현장에서 아연결정유약을 제조하여 사용할 때 조성원료에 따라 유약의 결정생성이 불안정하고, 특히 결정이 잘 생성되는 유약도 습식제조 후 시간이 경과하면 결정생성이 급격히 저하되는 문제점이 있다. 도예가들이 주로 사용하는 산화아연(ZnO)과 하소아연(calcined ZnO), 프리트 3110, 그리고 규석을 출발 물질로 3성분계 실험을 통하여 아연결정 조성을 선택하고 선 연구된 소성 조건을 사용하였다. 유약을 제조하고 1일~24주까지 습식으로 보관하면서 침수 과정에서 아연이 아연결정유의 결정생성에 미치는 영향을 규명하고자 하였다. 원료 입도 및 침수 영향을 측정하기 위해 입도분석, XRD, Raman Spectroscopy 그리고 SEM 분석 등을 하였다. 연구결과, 산화아연은 습식으로 유약 사용 시 willemite 결정 생성 및 성장이 우수하지만 유약을 보관하는 동안 ZnO가 물과 반응하여 Zn(OH)2를 생성하고 응집되면서 유약내 ZnO량이 감소되어 willemite 생성을 저해하여 결정이 감소됨을 확인하였다.