• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제10회 학술발표회 논문개요집
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• pp.102-102
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• 1996

This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.

• Applied Microscopy
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• 제47권1호
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• pp.55-62
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• 2017

This paper describes experiments aimed at characterizing the behavior of field electron emitters fabricated by coating carbon fibers with epoxylite resin. Polyacrylonitrile carbon fibers of type VPR-19, thermally treated at $2,800^{\circ}C$, were used. Each was initially prepared in a "uncoated" state, by standard electro polishing and cleaning techniques, and was then examined in a scanning electron microscope. The fiber was then baked overnight in a field electron microscope (FEM) vacuum chamber. Current-voltage characteristics and FEM images were recorded on the following day or later. The fiber was then removed from the FEM, coated with resin, "cured" by baking, and replaced in the FEM. After another overnight bake, the FEM characterization measurements were repeated. The coated fibers had significantly better performance than uncoated fibers. This confirms the results of earlier experiments, and is thought to be due in part to the formation of a conducting channel in the resin over layer. For the coated fiber, lower voltages were needed to obtain the same emission current. The coated fibers have current-voltage characteristics that show smoother trends, with greater stability and repeatability. No switch-on phenomena were observed. In addition, the emission images on the phosphor-coated FEM screen were more concentrated, and hence brighter.

• 전기전자학회논문지
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• 제19권1호
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• pp.41-44
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• 2015

소자의 집적화에 필수적인 소자 분리공정에서 화학약품의 오염 문제등을 발생시키는 화학적 기계연마기술(CMP) 공정을 사용하지 않고 벌크 finFET(fin field effect transistor) 의 트랜치 구조를 형성할 수 있는 공정에 대하여 제안하였다. 사진 감광막 도포시 발생하는 두께차이와 희생층으로 사용되는 실리콘 질화막을 사용하면 에칭 공정만을 사용하여 상대적으로 표면 위로 돌출된 부분의 실리콘 산화막 층을 에칭하는 것은 물론 finFET 의 채널로 사용되는 실리콘 트랜치 구조를 한번에 형성할 수 있는 특징을 갖는다. 본 연구에서는 AZ1512 사진 감광막을 사용하여 50 나노미터급 실리콘 트랜치 구조를 형성하는 공정을 수행하였으며 그 결과를 소개한다.

• 한국정밀공학회지
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• 제20권5호
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• pp.218-224
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• 2003

This paper describes a novel MEMS integration technique on a CMOS chip. MEMS integration on CMOS circuit has many advantages in view of manufacturing cost and reliability. The surface topography of a CMOS chip from a commercial foundry has 0.9 ${\mu}{\textrm}{m}$ bumps due to the conformal coating on aluminum interconnect patterns, which are used for addressing each MEMS element individually. Therefore, it is necessary to achieve a flat mirror-like CMOS chip fer the microelectromechanical system (MEMS) such as micro mirror array. Such CMOS chip needs an additional thickness of the dielectric passivation layer to ease the subsequent planarization process. To overcome a temperature limit from the aluminum thermal degradation, this study uses RF sputtering of silicon nitride at low temperature and then polishes the CMOS chip together with the surrounding dummy pieces to define a polishing plane. Planarization reduces 0.9 ${\mu}{\textrm}{m}$ of the bumps to less than 25 nm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.52-56
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• 2006

Some of factors affecting photo-conversion efficiency of dye sensitized solar cells (DSCs) are discussed in terms of $TiO_2$ electrodes. The first topic is on the surface modification of $TiO_2$ nano-particles, which is associated with electron traps on the surface of $TiO_2$ nano-particles. The surface is modified with dye molecules under pressurized $CO_2$ atmosphere to increase the surface coverage of $TiO_2$ nano-particles with dye molecules. This increases Jsc because of an increase in the amount of dye molecules and a decrease in the amount of trapping sites on $TiO_2$ nano-particles. In addition, the decrease in the amount of trap sites increases Voc because decreases in Voc are brought about by the recombination of $I_2$ molecules with electrons trapped on the $TiO_2$ surfaces. Selective staining for tandem cells is proposed. The second topic is on the contact between a $SnO_2$/F transparent conductive layer (TCL) and nano-particles. Polishing the TCL surfaces with silica nano-particles increases the contact, resulting in Jsc increases. The third topic is the fabrication of ion-paths in $TiO_2$ layers. Electro-spray coating of $TiO_2$ nano-particles onto TCL is shown to be effective for fabricating ion-paths in $TiO_2$ layers, which increases Jsc.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.182-187
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• 2005

A large area micro mirror is an optical element that functions as changing an optical path by reflection in integrated optical system. We fabricated the large area silicon mirror by anisotropic etching using MEMS for implementation of integrated optical pickup. In this work, we report the optimum conditions to better fabricate and design, greatly improve mirror surface quality. To obtain mirror surface of $45^{\circ},\;9.74^{\circ}$ off-axis silicon wafer from (100) plane was used in etching condition of $80^{\circ}C$ with 40wt.% KOH solution. After wet etching, polishing process by MR fluid was applied to mirror surface for reduction of roughness. In the next step, after polymer coating on the polished Si wafer, the Si mirror was fabricated by UV curing using a trapezoid bar-type way structure. Finally, we obtained peak to valley roughness about 50 nm in large area of $mm^2$ and it is applicable to optical pickup using blu-ray wavelength as well as infrared wavelength.

• Progress in Superconductivity
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• 제12권2호
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• pp.118-123
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• 2011

The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

• 구강회복응용과학지
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• 제25권2호
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• pp.83-94
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• 2009

본 연구는 지르코니아의 연마 정도와 tribochemical coating 등 두 가지 표면처리가 두 가지 레진 시멘트, 즉 Bis-GMA 계 레진 시멘트와 자가접착형 레진 시멘트와의 결합력에 어떠한 영향을 미치는가를 연구 비교하였다. $1{\mu}m$과 $50{\mu}m$ 의 다이아몬드 디스크로 연마한 지르코니아 시편을 만들어 접착기전이 다른 두 가지 레진 시멘트 RelyX ARC(3M Espe, USA)와 RelyX Unicem(3M Espe, USA)으로 결합시켰다. 지르코니아 표면에 로카텍 시스템 처리를 한 군과 하지 않은 군을 비교해 지르코니아와 레진 시멘트 사이의 전단결합강도를 측정하여 다음과 같은 결론을 얻었다. 1. 로카텍 시스템으로 표면처리를 한 군이 하지 않은 군에 비해 높은 전단결합강도를 보였다(P < 0.001). 2. 로카텍 시스템으로 표면처리를 한 군에서는 $50{\mu}m$ 연마 군이 $1{\mu}m$ 연마 군에 비해 높은 전단결합강도를 보였으며 통계학적 유의성을 보였다(P <0.001). 그러나 로카텍 처리를 하지 않은 군에서는 $50{\mu}m$ 연마 군과 $1{\mu}m$ 연마 군 간의 차이는 없었다(P >0.01). 3. RelyX Unicem을 이용하여 접착한 군이 RelyX ARC를 이용하여 접착한 군에 비해 높은 전단결합강도를 보였다(P < 0.01). 본연구의 결과에 따르면, 새로운 형태의 자가접착형 레진 시멘트의 지르코니아와의 전단결합강도는 기존의 Bis-GMA 계 레진 시멘트보다 우수하였으나, 제조자의 지시와 달리 지르코니아 표면에 로카텍 처리를 하는 것이 전단결합강도의 증진에 매우 효과적이었다.

• The Journal of Advanced Prosthodontics
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• 제3권2호
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• pp.81-84
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• 2011

PURPOSE. The aim of this in vitro study was to investigate the adhesion of initial colonizer, Streptococcus sanguis, on resin, titanium and zirconia under the same surface polishing condition. MATERIALS AND METHODS. Specimens were prepared from Z-250, cp-Ti and 3Y-TZP and polished with $1 {\mu}m$ diamond paste. After coating with saliva, each specimen was incubated with Streptococcus sanguis. Scanning electron microscope, crystal violet staining and measurement of fluorescence intensity resulting from resazurin reduction were performed for quantifying the bacterial adhesion. RESULTS. Surface of resin composite was significantly rougher than that of titanium and zirconia, although all tested specimens are classified as smooth. The resin specimens showed lower value of contact angle compared with titanium and zirconia specimens, and had hydrophilic surfaces. The result of scanning electron microscopy demonstrated that bound bacteria were more abundant on resin in comparison with titanium and zirconia. When total biofilm mass determined by crystal violet, absorbance value of resin was significantly higher than that of titanium or zirconia. The result of relative fluorescence intensities also demonstrated that the highest fluorescence intensity was found on the surface of resin. Absorbance value and fluorescence intensity on titanium was not significantly different from those on zirconia. CONCLUSION. Resin specimens showed the roughest surface and have a significantly higher susceptibility to adhere Streptococcus sanguis than titanium and zirconia when surfaces of each specimen were polished under same condition. There was no significant difference in bacteria adhesion between titanium and zirconia in vitro.

• 대한치과보철학회지
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• 제38권3호
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• pp.336-347
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• 2000

Statement of problem. Luster loss in esthetic anterior ceromer restoration can occur and can be related with rough surface texture. Understanding durability of surface finishing methods like polishing and surface coating have critical importance. Purpose. This study evaluated the effect of tooth brushing and thermal cycling on surface luster of 3 ceromer systems (Artglass, Targis, Sculpture) treated with different surface finishing methods. Material and methods. Seventy-two samples were prepared: 12 for control group Z100, 12 for Artglass, 24 for Targis, and 24 for Sculpture. Half of the Targis and Sculpture were polished according to the manufacturer's recommendation. The rest of the samples were coated with staining and glazing solution for Targis and Sculpture, respectively. All specimens were subjected to 10,000 cycles between $5^{\circ}C\;and\;55^{\circ}C$ with 30 seconds dwell time. Tooth brushing abrasion tests were performed in a customized tooth brushing machine with 500g back and forth for 20,000 cycle. Luster comparisons were based on grading after direct observation, and light reflection area was measured with Image analysis software. Results. All materials showed an decrease in luster grade after thermal cycling and tooth brushing. The post-tooth brushing results revealed that the glazed Sculpture had greater mean luster grade than did any other groups. While, the stained Targis group showed greatest changes after tooth brushing (p < 0.05), polished Targis and Sculpture did not show significant changes. However, glazed Sculpture showed discretely fallen out glaze resin. Conclusion. From the results of this study, all of the ceromer specimens were much glossy than control composite group after tooth brushing. coatings used for Targis and Sculpture had not durability for long term use.