• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.2
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• pp.79-93
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• 1991

With the advent of ULSI, many problems in previous metallization techniques and interconnection materials have become more serious. In this work, selective deposition of copper to fill the submicron contact has been tried. After forming electro-deposited copper films on p-type (100) silicon wafer using 0.75M $CuSO_4{\cdot}$5H_2O$ as an electrolyte, the effect of deposition time, current density and concentration of an additive on film properties were investigated. Film thickness, particle size and resistivity were analyzed by Alpha Step, SEM and 4 - point probe measurement respectively. The deposition rate was about $0.5-0.6\mu\textrm{m}$/min at $2A/dm^2$ and the particle size increased with increasing current density. The resistivities of electro-deposited copper films were about $3-6{\mu}{\Omega}{\cdot}$cm for the particle size above $4000{\AA}$. By the addition of 0.2 g/l gelatin, the particle size was reduced to less than $0.1{\mu}m $ and selective plugging of copper on submicron contacts could be successfully achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.429-429
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• 2007

For various applications of liquid crystal displays (LCDs), the uniform alignment of liquid crystal (LC) molecules on treated surfaces is significantly important. Generally, a rubbing method has been widely used to align the LC molecules on polyimide (PI) surfaces. Rubbed PI surfaces have suitable characteristics, such as uniform alignment. However, the rubbing method has some drawbacks, such as the generation of electrostatic charges and the creation of contaminating particles. Thus, we strongly recommend a non contact alignment technique for future generations of large high-resolution LCDs. Most recently, the LC aligning capabilities achieved by ultraviolet and ion-beam exposures which are non contact methods, on diamond-like carbon (DLC) inorganic thin film layers have been successfully studied because DLC thin films have a high mechanical hardness, a high electrical resistivity, optical transparency, and chemical inertness. In addition, nitrogen-doped DLC (NDLC) thin films exhibit properties similar to those of the DLC thin films and a higher thermal stability than the DLC thin films because C:N bonding in the NDLC thin filmsis stronger against thermal stress than C:H bonding in the DLC thin films. Our research group has already studied the NDLC thin films by an ion-beam alignment method. The $SiN_x$ thin films deposited by plasma-enhanced chemical vapor deposition are widely used as an insulation layer for a thin film transistor, which has characteristics similar to those of DLC inorganic thin films. Therefore, in this paper, we report on LC alignment effects and pretilt angle generation on a $SiN_x$, thin film treated by ion-beam irradiation for various N ratios

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.92-99
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• 2009

Deeply-driven ground rod in the rainy season may contact with rainwater and ground water. When surge voltages are applied to the submerged ground rods, the ionization around the ground rods are occurred. Ionization in soil and/or water is affected in dynamic performance of ground rod systems. This work aims at studying the transient performance of ground rod system under impulse voltage using scale model in an electrolytic tank. The potential reduction and energy dispersion caused by ionization were treasured and quantitatively analyzed using the Matlab Program. As a result, the peak voltage at the terminal of ground rod was varied with water resistivity and charging voltage of Marx generator. The potential at the terminal of the ground rod was approximately reduced to a half of the applied voltage just below breakdown voltage. Also the energy more than half of the applied energy was dispersed through the ground rod due to ionization just below breakdown voltage.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.2007-2013
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• 2017

In order to give hydrophobic surface properties on carbon steel, the fluorinated amorphous carbon films were prepared by using linear 2.45GHz microwave PECVD device. Two different process approaches have been tested. One is direct deposition of a-C:H:F films using admixture of $Ar/CH_4/CF_4$ working gases and the other is surface treatment using $CF_4$ plasma after deposition of a-C:H film with $Ar/CH_4$ binary gas system. $Ar/CF_4$ plasma treated surface with high $CF_4$ gas ratio shows best hydrophobicity and durability of hydrophobicity. Nanometer scale surface roughness seems one of the most important factors for hydrophobicity within our experimental conditions. The properties of a-C:H:F films and $CF_4$ plasma treated a-C:H films were investigated in terms of surface roughness, hardness, microstructure, chemical bonding, atomic bonding structure between carbon and fluorine, adhesion and water contact angle by using atomic force microscopy (AFM), nano-indentation, Raman analysis and X-ray photoelectron spectroscopy (XPS).

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2396-2400
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• 2007

Transparent In-doped (1 at.%) zinc oxide (IZO) thin films are deposited by pulsed DC magnetron sputtering with H2 mixed Ar atmosphere on glass substrate without any heating process. Even at room temperature, highly c-axis oriented IZO thin films were grown in perpendicular to the substrate. The hydrogenated IZO (IZO:H) film isolated in H2 atmosphere for 30 min exhibited an average optical transmittance higher than 85% and low electrical resistivity of less than 2.7 × 10?3 Ω·cm. These values are comparable with those of commercially available ITO. Each of the IZO films was used as an anode contact to fabricate organic light-emitting diodes (OLEDs) and the device performances studied. At the current density of 1 × 103 A/m2, the OLEDs with IZO:H (H2) anode show excellent efficiency (11 V drive voltage) and a good brightness (8000 cd/m2) of the light emitted from the devices, which are as good as the control device built on a commercial ITO anode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.374-378
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• 2010

The effects of $O_2$ plasma pretreatment on the properties of Ga-doped ZnO films on polyimide substrate were studied. GZO films were fabricated by RF magnetron sputtering process. To improve surface energy and adhesion between the polyimide substrate and the GZO film, $O_2$ plasma pretreatment process was used prior to GZO sputtering. As the RF power and the treatment time increased, the crystallinity increased and the contact angle decreased significantly. When the RF power was 100 W and the treatment time was 120 sec, the resistivity of GZO films on the polyimide substrate was $1.90{\times}10^{-3}{\Omega}-cm$.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.55-60
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• 2009

Porous silicon film is fabricated by electrochemical etching in a chemical mixture of HF and ethanol. Effects of Si type, Si resistivity, ultrasonic frequency, current density and etching time on surface morphology of PS film were studied. Electrochemical etching in ultrasonic bath promotes the uniformity of porous layer of Si. Frequency of ultrasonic was increased from 40 kHz to 130 kHz to obtain uniform pores on the Si surface. When current density was higher, the sizes of pores were larger. The new etching cell using back contact metal and current shield help to overcome nonhomogeneity and current crowding effect, and then leads to fabricate uniform pores on the Si surface. The distribution of pore size shows no notable tendency with etching time.

• Journal of the Korean Electrochemical Society
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• v.4 no.1
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• pp.10-13
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• 2001

Effects of an anionic surfactant pentadecafluorooctanoic acid on the photoluminescence of porous silicon was investigated, which was prepared by photoelectrochemical etching at 4V of single crystalline n-type silicon (100) with the specific resistivity of $0.4\~0.8{\Omega}{\cdot}cm$. Photoluminescence shifted to shorter wavelength and its intensity decreased when the concentration of the surfactant increased. FT-IR and contact angle data supported the presence of the surfactant lying on the surface of porous silicon.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.1-11
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• 2014

Flexible transparent conductive electrodes (TCEs) have recently attracted a great deal of attention owing to rapid advances in flexible electronic devices, such as flexible displays, flexible photovoltanics, and e-papers. As the performance and reliability of flexible electronics are critically affected by the quality of TCE films, it is imperative to develop TCE films with low resistivity and high transparency as well as high flexibility. Indium tin oxide (ITO) has been the most dominant transparent conducting material due to its high optical transparency and electrical conductivity. However, ITO is susceptible to cracking and delamination when it is bent or deformed. Therefore, various types of flexible TCEs, such as carbon nanotube, conducting polymers, graphene, metal mesh, Ag nanowires (NWs), and metal mesh have been extensively investigated. Among several options to replace ITO film, Ag NWs and metal mesh have been suggested as the promising candidate for flexible TCEs. In this paper, we focused on Ag NWs and metal mesh, and summarized the current development status of Ag NWs and metal mesh. The several critical issues such as high contact resistance and haze are discussed, and newly developed technologies to resolve these issues are also presented. In particular, the flexibility and durability of Ag NWs and metal mesh was compared with ITO electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.458.2-458.2
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• 2014

We have demonstrated that simple brush-painted Ti-doped $In_2O_3$(TIO) films can be used as a cost effective transparent anodes for organic solar cells (OSCs). We examined the RTA effects on the electrical, optical, and structural properties of the brush painted TIO electrodes. By the direct brushing of TIO nanoparticle ink and rapid thermal annealing (RTA), we can simply obtain TIO electrodes with a low sheet resistance of 28.25 Ohm/square and a high optical transmittance of 85.48% under atmospheric ambient conditions. Furthermore, improvements in the connectivity of the TIO nano-particles in the top region during the RTA process play an important role in reducing the resistivity of the brush-painted TIO anode. In particular, the brush painted TIO films showed a much higher mobility ($33.4cm^2/V-s$) than that of previously reported solution-process transparent oxide films ($1{\sim}5cm^2/V-s$) due to the effects of the Ti dopant with higher Lewis acid strength (3.06) and the reduced contact resistance of TIO nanoparticles. The OSCs fabricated on the brush-painted TIO films exhibited cell-performance with an open circuit voltage (Voc) of 0.61 V, shot circuit current (Jsc) of $7.90mA/cm^2$, fill factor (FF) of 61%, and power conversion efficiency (PCE) of 2.94%. This indicates that brush-painted TIO film is a promising cost-effective transparent electrode for printing-based OSCs with its simple process and high performance.