• 한국전기전자재료학회논문지
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• 제33권6호
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• pp.450-453
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• 2020

In this study, ZnO:Ga thin films were fabricated on a glass substrate using various Ar flows by an RF magnetron sputter system at room temperature. The dependencies of Ar flow on different properties were investigated. An appropriate control over the Ar flow led to the formation of a high-quality thin film. The ZnO:Ga films were formed as a hexagonal wurtzite structure with high (002) preferential orientation. The films exhibited a typical columnar microstructure and a smooth top face. The average transmittance was 85~89% within the visible area. By decreasing the Ar flow, the sheet resistance was decreased due to an increase in the grain size and a decrease in the root mean square roughness. The lowest sheet resistance of 86 Ω/□ was obtained at room temperature for the 40 sccm Ar flow.

• 한국진공학회지
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• 제8권3A호
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• pp.218-223
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• 1999

We investigated the interfacial reactions between the $Y_2O_3$ film deposited by ICB processing and p-type (100) Si substrates upon annealing treatments in $O_2$ and Ar gas ambients. we also investigated the evolution of surface morphology of ICB deposited $Y_2O_3$ films upon annealing treatments. We observed that the root-mean-square(RMS) value of surface roughness measured by AFM increased with annealing time at $800^{\circ}C$ in $O_2$ ambient, while the change of surface roughness was not observed in Ar ambient. We also found the growth of $SiO_2$ layer and the formation of yttium silicate layer. From the capacitance values $(C_{acc})$ measured by C-V measurements, the relative didldctric constant of $Y_2O_3$ film in metal-insulator-semiconductor(MIS) structure was estimated to be about 9.

• 한국재료학회지
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• 제8권10호
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• pp.890-897
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• 1998

n-InP(001)기판과 PECVD법으로 ${Si}_3N_4$(200nm)막이 성장된 InP 기판사이의 direct wafer bonding을 분석하였다. 두 기판을 접촉시켰을 때 이들 사이의 결합력에 크게 영향을 주는 표면 상태를 접촉각 측정과 AFM을 통해서 분석하였다. InP 기판은 $50{\%}$ 불산용액으로 에칭하였을 때 접촉각이 $5^{\circ}$, RMS roughness는 $1.54{\AA}$이었다. ${Si}_3N_4$는 암모니아수 용액으로 에칭하였을 때 RMS roughness가 $3.11{\AA}$이었다. Inp 기판과 ${Si}_3N_4$/InP를 각각 $50{\%}$ 불산 용액과 암모니아수 용액에 에칭한 후 접촉시켰을 때 상당한 크기의 초기 겹합력을 관찰할 수 있었다. 기계적으로 결합된 시편을 $580^{\circ}C$-$680^{\circ}C$, 1시간동안 수소 분위기와 질소분우기에서 열처리하였다. SAT(Scanning Acoustic Tomography)측정으로 두 기판 사이의 결합여부를 확인하였다. shear force로 측정한 InP 기판과 ${Si}_3N_4$/InP사이의 결합력은 ${Si}_3N_4$/InP 계면의 결합력만큼 증가되었다. TEM과 AES를 이용해서 di-rect water bonding 계면과 PECVD계면을 분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.106-111
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• 1993

This experimental study mainly deal with the single and multi-insert cutting characteristics using coated tool. Because metal cutting of the single and multi-insert has a large relation to the improvement of productivity, the economic cutting process can be achieved by the analysis of proper metal cutting mechanism. Therefore, machining characteristics of face milling in this paper has been studied by investigating the role of different insert number which is concerned with mean cutting force, the RMS values of AE(acoustic emission) signal, tool life and surface roughness in milling SS 41 and SUS 304.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.422-427
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• 2003

Sapphire have been ground by the ultra-precision surface grinder having a glass -ceramic spindle of extremely-low thermal expansion with various cup-type resinoid-bonded diamond wheels of #400-#3000 in grain size. Sapphire can be ground in the ductile mode. And also, the surface roughness and grinding conditions has been clarified. The smooth surface of Sapphire less than 1nm RMS, 1nm Ra can be obtained by the ultra-precision grinding without any polishing Process.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2004년도 High Temperature Superconductivity Vol.XIV
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• pp.92-92
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• 2004

• Macromolecular Research
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• 제10권5호
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• pp.291-295
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• 2002

Atomic force microscopy(AFM) was used to study the polyethylene(PE) surfaces grafted and immobilized with acrylic acid by Ar plasma treatment. The topographical images and parameters including RMS roughness and Rp-v value provided an appropriate means to characterize the surfaces. The plasma grafting and immobilization method were a useful tool for the preparation of surfaces with carboxyl group. However, the plasma immobilization method turned out to have a limitation to use as a means of preparation of PE surface with specific functionalities, due to ablation effect during the Ar plasma treatment process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.205-205
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• 2009

As a p-type semiconductor NiO is potential material which can be used in many application including QD-LED. NiO films were deposited on glass substrates using rf-sputtering method. The properties of resistivity, surface roughness, etc in the NiO films were investigated at different sputtering parameters. The resistivity of $l.88{\times}10^{-2}{\sim}3.71{\times}10^{-2}{\Omega}cm$ with sputtering power(80~200 watts) and change was very low. The sputtering pressure at 3~60 mTorr resulted in rather broad change ofresistivity of $0.58{\times}10^{-2}{\sim}4.67{\Omega}cm$. The oxygen content in sputtering gas was found to be very effective to control the resistivity from $2.01{\times}10^{-2}$ to $1.22{\times}10^2{\Omega}cm$ with 100~2.5% $O_2$ in Ar gas. In addition, the surface roughness showed the RMS values of 0.6~1.1 nm and the dependence on sputtering parameters was weak.

• 전기학회논문지
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• 제58권6호
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• pp.1146-1150
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• 2009

Cadmium telluride (CdTe) is one of the most attractive photovoltaic materials due to its low cost, high efficiency and stable performance in physical, optical and electronic properties. Few researches on the influences of uniform surface on the photovoltaic characteristics in large-area CdTe solar cell were not reported. As the preceding study of the effects of thickness-uniformity on the photovoltaic characteristics for the large-area CdTe thin film solar cell, chemical mechanical polishing (CMP) process was investigated for an enhancement of thickness-uniformity. Removal rate of CdTe thin film was 3160 nm/min of the maximum value at the 200 $gf/cm^2$ of down force (pressure) and 60 rpm of table speed (velocity). The removal rate of CdTe thin film was more affected by the down force than the table speed which is the two main factors directly influencing on the removal rate in CMP process. RMS roughness and peak-to-valley roughness of CdTe thin film after CMP process were improved to 96.68% and 85.55%, respectively. The optimum process condition was estimated by 100 $gf/cm^2$ of down force and 60 rpm of table speed with the consideration of good removal uniformity about 5.0% as well as excellent surface roughness for the large-area CdTe solar cell.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.234-243
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• 1999

Using the geometric and the vector methods, three dimensional surface texture and roughness models in flat end milling are developed. In these models, rear cutting effect on surface generation is considered along with tool run-out and tool setting error including tool tilting and eccentricity between tool center and spindle rotational center. Rear cutting is the secondary cutting of the already machined surface by the trailing cutting edge. The effects of tool geometry and tool deflection on surface roughness are also considered. For representing the surface texture more practically, three dimentional surface topography parameters such as RMS deviaiton, skewness and kurtosis are introduced and used in expressing the surface texture characteristics. Under various cutting conditions, it is confirmed that the developed models predict the real surface profile precisely. These models could contribute to the cutter design and cutting condition selection for the reduction of machining and manual finishing time.