• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.157-157
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• 2011

Graphene has generated significant interest in the recent years as a functional material for electronics, sensing, and energy applications due to its unique electrical, optical, and mechanical properties. Much of the considerable interest in graphene stems from results obtained for samples mechanically exfoliated from graphite. Practical applications, however, require reliable and well-controlled methods for fabrication of large area graphene films. Recently high quality graphene layers were fabricated using chemical vapor deposition (CVD) on nickel and copper with methane as the source of the carbon atoms. Here, we report a simple and efficient method to synthesize graphene layers using solid carbon source. Few-layer graphene films are grown using filtered vacuum arc source (FVAS) technique by evaporation of carbon atom on Ni catalytic metal and subsequent annealing of the samples at 800$^{\circ}$C. In our system, carbon atoms diffuse into the Ni metal layer at elevated temperatures followed by their segregation as graphene on the free surface during the cooling down step as the solubility of carbon in the metal decrease. For a given annealing condition and cooling rate, the number of graphene layers is easily controlled by changing the thickness of the initially evaporated amorphous carbon film. Based on the Raman analysis, the quality of graphene is comparable to other synthesis methods found in the literature, such as CVD and chemical methods.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.121-125
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• 2004

Nickel oxide (NiO) thin films were deposited on Si(100) substrates at room temperature by RF magnetron sputtering from a NiO target. The effects of plasma gas and RF power on the crystallographic orientation and surface morphology of the NiO films were investigated. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were employed to characterize the deposited film. It was found that the type of plasma gases affected the crystallographic orientation, deposition rate, surface morphology, and crystallinity of NiO films. Highly crystalline NiO films with (100) orientation were obtained when it was deposited under Ar atmosphere. On the other hand, (l11)-oriented NiO films with poor crystallinity were deposited in $O_2$. Also, the increase in RF power resulted in not only higher deposition rate, larger grain size, and rougher surface but also higher crystallinity of NiO films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.448-448
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• 2007

OLED has many advantages of low voltage operation, self radiation, light weight, thin thickness, wide view angle and fast response time to overcome existing liquid crystal display (LCD)'s weakness. Therefore, It draws attention as promising display and has already developed for manufactured goods. Also, OLED is regarded as a only substitute of flexible display with a thin display. However, Indium tin oxide(ITO) thin film for electrode of OLED shows a low electrical properties and is impossible to deposit at high thermal condition because electrical characteristics of ITO is getting worse. One of the ways to realize an improved flexible OLED is to use high internal efficiency electrodes, which have higher work function than those single layer of ITO films of the same thickness. The high internal efficiency electrodes film is developed with structure of nickel oxide for bottom Emission Type of OLED.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.48-56
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• 2011

Black cobalt solar selective coatings were prepared by thermal oxidation of electroplated cobalt metal on copper and nickel substrates. The optical properties and structure of the black cobalt selective coating for solar energy utilizations were characterized by glow discharge spectrometry (GDS), ultraviolet-visible-near infrared (UV-VIS-NIR) spectrometer, atom force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). The optical properties of optimum black cobalt selective coating prepared on copper substrate were a solar absorptance of 0.82 and a thermal emittance of 0.01. From the GDS depth profile analysis of these coatings, the concentration of cobalt particles near the interface was higher than at the surface, but oxygen concentration at the surface was higher than at the interface. These results suggest that the selective absorption was dominated by this chemical composition variation in the coating. The surface of this film exhibited morphology with root-mean-square(rms) roughness of about 144.3nm. XPS measurements data showed that several phases of Co coexist($Co_3O_4$,CoO) in the film.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.61-66
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• 2012

Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.631-635
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• 2006

The properties of metal interlayered DLC films between the Si substrate and the DLC films were studied. DC magnetron sputtering method has been used to deposit intermediate layers of metals. And RF-PECVD method has been employed to synthesize DLC onto substrates of the silicon and metal layers. After we used metal Inter-layers, such as chromium, nickel, titanium and we studied tribological properties of the DLC films. The thickness of films were observed by field emission scanning electron microscope (FE-SEM). Also the surface morphology of the films were observed by an atomic force microscope (AFM). The crystallographic properties of the films were analyzed with X-ray diffraction (XRD), the friction coefficients were investigated by AFM in friction force microscope (FFM) mode. Tribological performances of the films were estimated by nano-indenter, stress tester measurement.

• Journal of the Korean Applied Science and Technology
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• v.28 no.1
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• pp.48-56
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• 2011

In this study, we investigated the C-V diagrams and metal surface related to the electrochemistry characterization of metal(nickel, SUS-304). We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150, 200 and 250 mV/s. As a result, the C-V characterization of metal using N,N-dimethylacetamide and N,N-dimethylformamide inhibitors appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding organic corrosion inhibitors, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the addition of inhibitors containing amide functional group enhances the corrosion resistance properties.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.48-53
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• 1998

Poly-Si TFT's could be fabricated on glass substrates by metal induced lateral crystallization (MILC) method at 450.deg. C. Channel area of the poly-Si TFT's was laterally crystallized from source and drain areas, where a thn nickel film was deposited. Dopants activation for the formation of source and drain region could be achieved by thermal annealing at 450.deg. C after the ion mass doping of phosphorus. The field effect mobility of thus formed N-channel poly-Si TFT's was 76cm$^{2}$/Vs, and the on/off current ratio was higher than 7E6.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.159-164
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• 2005

The Hot Embossing Lithography(HEL) as a method fur the fabrication of the nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this paper, we carried out experimental studies and numerical simulations in order to understand the viscous flow of the polymer (PMMA) film during the hot embossing process. To grasp the characteristics of the micro patterning rheology by process parameters (embossing temperature, pressure and time), we have carried out various experiments by using the nickel-coated master fabricated by the deep RIE process and the plasma sputtering. During the hot embossing process, we have observed the characteristics of the viscoelastic behavior of polymer. Also, the viscous flow during the hot embossing process has been simulated by the continuum based FDM(Finite Difference Method) analysis considering the micro effect, such as a surface tension and a contact angle.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.865-871
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• 2005

Submicron thick solid electrolyte membrane is essential to the implementation of low temperature solid oxide fuel cell, and, therefore, development of new electrode structures is necessary for the submicron thick solid electrolyte deposition while providing functions as current collector and fuel transport channel. In this research, a nickel membrane with multi-stage nano hole array has been produced via modified two step replication process. The obtained membrane has practical size of 12mm diameter and $50{\mu}m$ thickness. The multi-stage nature provides 20nm pores on one side and 200nm on the other side. The 20nm side provides catalyst layer and $30\~40\%$ planar porosity was measured. The successful deposition of submicron thick yttria stabilized zirconia membrane on the substrate shows the possibility of achieving a low temperature solid oxide fuel cell.