• 한국표면공학회지
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• 제49권3호
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• pp.307-315
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• 2016

The properties of AlTiN films by a cathodic arc deposition process have been studied. Oblique angle deposition has been applied to deposit AlTiN films. AlTiN films have been deposited on stainless steel (SUS304) and cemented carbide (WC) at a substrate temperature of $500^{\circ}C$. AlTiN films were analyzed by scanning electron microscopy, glow-discharge light spectroscopy, micro-vickers hardness, and nanoindenter. When applying a current of 50 A to the cathodic arc source, it showed that the density of macroparticle of AlTiN films was 5 lower than other deposition conditions. With the increase of the bias voltage applied to the substrate up to -150 V, the density of macroparticle was decreased. The change of the $N_2$ flow rate during coating process made no influence on the film properties. For the multi-layered films, the film prepared at oblique angle of $60^{\circ}$ showed the highest hardness of 28 GPa and $H^3/E^2$ index of 0.18. AlTiN films have been shown a good oxidation resistance up to $800^{\circ}C$.

• 한국염색가공학회지
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• 제6권3호
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• pp.27-36
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• 1994

In order to produce a water repellent surface on polyester fabric, samples were treated in the atmosphere of $CF_4$ glow discharge plasma. The samples used in the study were ployester fabric and poyester film. The purpose of film treatment is for the comparison of hydrophobicity with fabric sample at same treatment condition. Radio frequency(13.56MHz) generator was used as electric source and its in put power is 100 Watt. Water repellency was evaluated by contact angle measurement. Result obtained are as follows. 1) Fiber interstice of original fabric was ana lysed as 0.43$\mu$m, and this value was sufficiently ideal for making water repellent fabric. 2) The most favorable setting position of substrate was the center area between two electrodes. 3) Fabric contact angle was higher than film contact angle at same treatment condition, and its difference was more than 50${\circ}$. And it was incapalbe of fabric contact angle measurement when the film contact angle was less than 90${\circ}$. because the fabric is susceptible to absorption of water by the capillary effect. 4) Fabric contact angle can not revealed the precise defferences of surface hydrophobicity, however, the film contact angle showed the real hydrophobic nature. 5) It was not sufficient method to evaluate the hydrophobicity of fabric surface by merely measure of the water contact angle. 6) It showed high water repellent nature at 0.06 torr of $CF_4$ plasma gas pressure and duration of 45 seconds treatment, and it can not be anticipated more improved nature if the pressure and duration of treatment time were increased.

• 한국재료학회지
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• 제14권3호
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• pp.203-210
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• 2004

Effects of various pretreatments on the adhesion of copper-coated polymer films were investigated. Copper-coated polymer films were prepared by an electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) coupled with a DC bias system at room temperature. PET(polyethylene terephthalate) film was employed as a substrate material and it was pretreated by industrially feasible methods such as chromic acid, sand-blasting, oxygen plasma and ion-implantation treatment. Surface characterization of the copper-coated polymer film was carried out by AFM(Atomic Force Microscopy) and FESEM(Field Emission Scanning Electron Microscopy). Surface energy was calculated by based on the value of the contact angle measured. The adhesion of copper/PET films was determined by a pull-off test according to ASTM D-5179. It was found that suitable pretreatment of the PET substrate was required for obtaining good adhesion property between copper films and the substrate. In this study the highest adhesion was observed in sand-blasting, and then followed by those of acid and oxygen plasma treatment. However, the effect of surface energy was insignificant in our experimental range. This is probably due to compensating the difference in surface energy from various pretreatments by exposing substrate to ECR plasma for 5 min or longer at the early stage of the copper deposition. Therefore, it can be concluded that surface roughness of the polymer substrate plays an important role to determine the adhesion of copper-coated polymer for the deposition of copper by ECR-MOCVD.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.913-918
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• 2005

It is expected that the inkjet technology offers prospect for reliable and low cost manufacturing of FPD (Flat Panel Display). This inkjet technology also offers a more simplified manufacturing process for various part of the FPD than conventional process. For example, recently the novel manufacturing processes of color filter (C/F) in LCD, or RGB patterning in OLED by inkjet printing method have been developed. This elaborates will be considered as the precious point of manufacturing process for the mass production of enlarged-display panel with a low price. On this point of view, we would like to review the status of inkjet technology in FPD, with some results on forming micro line by inkjet patterning of suspension type silver nano ink as below. We have studied the inkjet patterning of synthesized aqueous silver nano-sol on interface-controlled ITO glass substrate. Furthermore, we designed the conductive ink for direct inkjet patterning on bare ITO glass substrate. The first, the highly concentrated polymeric dispersant-assisted silver nano sol was prepared. The high concentration of batch-synthesized silver nano sol was possible to 40 wt%. At the same time the particle size of silver nanoparticles was below $10{\sim}20nm$. The second, the synthesized silver nano sol was inkjet - patterned on ITO glass substrate. The connectivity and width of fine line depended largely on the wettability of silver nano sol on ITO glass substrate, which was controlled by surfactant. The relationship was understood by wetting angle. The line of silver electrode as fine as $50{\sim}100\;{\mu}m$ was successfully formed on ITO glass substrate. The last, the direct inkjet-patternable silver nano sol on bare ITO glass substrate was designed also.

• 전자공학회논문지
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• 제49권12호
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• pp.95-110
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• 2012

유한한 기판 크기가 2 소자 E-평면 마이크로스트립 패치 선형 위상 배열 안테나의 방사 특성에 미치는 영향에 대하여 연구하였다. 서로 다른 유전상수를 가지는 기판을 이용하여 2 소자 E-평면 배열 안테나의 기판 크기에 따른 평균 능동소자패턴 특성을 분석하고 빔 주사각도에 따른 배열 안테나의 방사패턴 특성을 분석하였다. 전산모의 실험 결과 E-평면상에 배열된 2 소자 배열안테나의 방사패턴은 주로 E-평면 기판 가장자리에서 회절되어 방사되는 필드에 의해 결정되며 안테나 소자 간 상호 결합으로 인한 기생 방사가 배열 안테나의 방사패턴에 미치는 영향은 상대적으로 작게 나타났다. 안테나 소자 중심에서 E-평면 방향 기판 가장자리까지의 거리가 $0.35{\lambda}_0$ 일 때 배열 안테나의 방사패턴 특성이 가장 향상되었다.

• 전기학회논문지
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• 제59권3호
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• pp.588-593
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• 2010

Sputter deposition on a Pt counter electrode was studied using radio frequency (RF) plasma as the improvement of incident photon to current conversion efficiency (IPCE) for dye-sensitized solar cells (DSCs). Effects of the sputtering thickness and the incident angle on a Pt counter electrode for DSCs were investigated. Experiments to get the optimal sputtering time for the performance of the DSCs were carried out. And it is found that the optimized sputtering time was 120 seconds, in addition, the incident angles of the substrate was adjusted from $0^{\circ}$ to $60^{\circ}$. The maximum efficiency of 5.37% was obtained at the incident angle of $40^{\circ}$ with an active cell area of $1cm^2$.

• ETRI Journal
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• 제31권3호
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• pp.271-281
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• 2009

This paper presents a novel multiband microstrip-fed right angle slot antenna design technique for multiple independent frequency bands. The new technique uses various slot sizes at various appropriate positions. We first propose a tri-band slot antenna consisting of three right angle slots. Then, a quad-band slot antenna is developed with four right angle slots which achieves slant ${\pm}45^{\circ}$ linear polarization, omnidirectional pattern coverage, good antenna gain, and acceptable impedance bandwidths over all the operating frequency range. Moreover, an open-circuited tuning stub is introduced to achieve good impedance matching. Both proposed antennas are designed on a ground plane of RT/duroid 5880 substrate with a thickness of 1.575 mm. The real measurable results show that the desired frequencies used in wireless communication systems, namely, WLAN and WiMax, are efficiently achieved.

• 대한기계학회논문집B
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• 제27권7호
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• pp.956-962
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• 2003

The Lippmann-Young equation has been widely used in electrowetting to predict the contact-angle change of a droplet on a insulating substrate with respect to the externally-applied electrical voltage. The Lippmann-Young equation is derived by assuming a droplet as a perfect conductor, so that the effect of the electrical double layer and the line tension are not taken into account. The validity of the assumption has never been checked before, systematically. In the present investigation, a modified Lippmann-Young equation is derived taking into account of the effect of the electrical double layer and the line tension. To assess their influence on contact-angle change in electrowetting, the electrostatic field around the three-phase contact line is analyzed by solving the Poisson-Boltzmann equation numerically. The validity of the numerical methods is verified by using the past theoretical results on the electrostatic field around a wedge-shaped geometry, which shows fairly good agreement. The results of the present investigation clearly indicate that the effect of the electrical double layer and the line tension is negligible for a millimeter-sized droplet. On the other hand, for a micron-sized droplet, the effect of the line tension can become a dominating factor which controls the contact-angle change in electrowetting.

• 한국표면공학회지
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• 제44권2호
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• pp.50-54
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• 2011

Hydrophobic a-C:F film was coated on polycarbonate film with $CF_4$, $C_2F_6$ and HFC ($C_2F_4H_2$) gas in helium discharge generated by 5~100 kHz AC power supply at atmospheric pressure and room temperature. The highest water contact angle of the a-C:F film formed with $He/C_2F_6$ mixed gas is $155^{\circ}$. X-ray photoelectron spectrum showed that there was 40% of C-$CF_3$ bond at the surface of the super hydrophobic film. The contact angle and deposition rate were decreased with increasing substrate temperature. The contact angle was generally increased with the surface roughness of the film. The contact angle was high when the surface microstructure of the film was fine and sharp at the similar roughness and chemical composition of the surface.

• 마이크로전자및패키징학회지
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• 제6권1호
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• pp.1-10
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• 1999

본 논문에서는 평탄형 GaAs 기판과 $2^{\circ}$, $6^{\circ}$, $10^{\circ}$경사형 GaAs 기판 등 네 종류의 기판에 유기금속 기강성장장치를 이용하여 InGaP 에피막을 성장시켰고, 기판-에피막간의 격자부정합, 탄성변형, 격자굴곡, 부정합응력 등을 측정하여 기판 경사도, 즉 misorientation이 InGaP 에피막의 탄성특성에 미치는 영향에 대해 최초로 연구하였다. 또한 에피막의 x-선 반치폭과 PL강도 및 PL 반치폭, 발진파장 등을 측정하여 기판의 경사도가 에피막의 결정질에 미치는 영향에 대하여도 연구하였다. 시료 분석은 TXRD(tripple-axis x-ray diffractometer)와 저온 (11K) PL(photoluminescence)를 이용하여 수행했다. 기판 경사도 증가에 따라 Ga 원자의 흡착율이 평탄기판의 경우에 비해 상대적으로 증가하였으며, x-선 반치폭이 감소하였다. 또한 선형 탄성이론에 입각하면 격자 misfit 감소에 따라 부정합응력도 감소해야 하나, 반대로 미세하게 증가하는 현상이 관측되었으며 이는 경사기판을 사용할 때 접계면의 에피막 원자의 탄성효율이 향상되는 것에 기인함을 밝혔다. 그리고 기판의 경사도가 증가함에 따라 PL발진파장이 감소하였고, PL 강도는 증가하였으며, PL 반치폭은 감소하였다. 따라서 본 연구에서는 경사기판을 사용할 때 접계면의 탄성효율이 향상되고, InGaP 에피막의 결정질이 향상됨을 밝혔다.