• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.5-11
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• 2004

Optical properties of PET(Polyethylene terephthalate), PC(Polycarbonate), Acrylic resin and PE(Polyethylene) sheets were studied as a function of heat treating temperature of $60^{\circ}C$ to $150^{\circ}C$. By the heat treatment, optical properties of transmittance, absorbance, and reflectance showed a considerable change with different ways according to the materials. To understand the reason of optical property change, X-ray diffraction and surface morphology were also investigated. It was observed that small crystallite and pore that can cause scattering largely affect the transmittance. It was suggested that change of surface chemical bond induce the reflectance variation.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.31-35
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• 2003

We present a formation technique of thin film heater for heat transfer components. Thin film structures of Cr-Si have been prepared on top of alumina substrates by magnetron sputtering. More samples of Mo thin films were prepared on silicon oxide and silicon nitride substrates by electron beam evaporation technology. The electrical properties of the thin film structures were measured up to the temperature of $500^{\circ}C$. The thickness of the thin films was ranged to about 1 um, and a post annealing up to $900^{\circ}C$ was carried out to achieve more reliable film structures. In measurements of temperature coefficient of resistance (TCR), chrome-rich films show the metallic properties; whereas silicon-rich films do the semiconductor properties. Optimal composition between Cr and Si was obtained as 1 : 2, and there is 20% change or less of surface resistance from room temperature to $500^{\circ}C$. Scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) were used for the material analysis of the thin films.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.116-119
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• 2017

In this paper, natural convection around the ambient evaporator was numerically studied using commercial computational fluid dynamics software. From the simulations, temperature and velocity fields around the evaporator were found as a function of evaporator size and liquefied gas flow rate. The heat transfer coefficient at the external surface of the evaporator was also calculated from the simulation results. In order to give the heat transfer coefficient for various conditions, correlation between Rayleigh number and Nusselt number was proposed.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.65-69
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• 2017

This paper presents a Technology-CAD (TCAD) simulation of the characteristics of crystalline Si pillar array solar cells. The junction depth and the surface concentration of the solar cells were optimized to obtain the targeted sheet resistance of the emitter region. The diffusion model was determined by calibrating the emitter doping profile of the microscale silicon pillars. The dimension parameters determining the pillar shape, such as width, height, and spacing were varied within a simulation window from ${\sim}2{\mu}m$ to $5{\mu}m$. The simulation showed that increasing pillar width (or diameter) and spacing resulted in the decrease of current density due to surface area loss, light trapping loss, and high reflectance. Although increasing pillar height might improve the chances of light trapping, the recombination loss due to the increase in the carrier's transfer length canceled out the positive effect to the photo-generation component of the current. The silicon pillars were experimentally formed by photoresist patterning and electroless etching. The laboratory results of a fabricated Si pillar solar cell showed the efficiency and the fill factor to be close to the simulation results.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.185-190
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• 2004

Plasma Display Panel is a display device emitting fluorescent light from gas discharge between a front and a rear panel sealed together. Front and rear panel have multitude of film layers and barrier ribs in the rear panel has the largest area so releasing various gases and affecting light emitting characteristics and lifetime. The remaining gases in a barrier rib were studied by thermal desorption analysis up to $400^{\circ}C$ and main gases were $H_2$ $H_2$O, CO. During sustaining at $300^{\circ}C$, the outgassing rates from other gases were decreased but$ H_2$ kept constantly increasing until 1 hour, which can be originated from the dissociation of organics remained in the inside of barrier rib material. In $H_2$O, two distinct peaks were observed: desorption from physically adsorbed one at $l00^{\circ}C$ and from chemically adsorbed one $400^{\circ}C$. The result can be utilized in interpretation of electronic and optical characteristics and evacuation process control of PDP

• Journal of Information Display
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• v.8 no.3
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• pp.22-28
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• 2007

We reported the diffraction analysis of the liquid crystal (LC) binary gratings and the surface anchoring energies for planar and homeotropic alignments. The planar and homeotropic anchoring energies were directly derived based on the linearly distorted director distribution near domain boundaries, in which the distorted lengths correspond to the extrapolation lengths into both planar and homeotropic regions. From the diffraction analysis for the LC binary gratings with various grating periods based on the linearly graded phase model, both distorted lengths into planar and homeotropic regions were simultaneously obtained. In this work, the planar and homeotropic anchoring energies were found to be about $1.4\;{\times}\;10^{-4}\;J/m^2$ and $0.9\;{\times}\;10^{-5}\;J/m^2$, respectively.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.57-60
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• 2015

Electric power in large devices is controlled by digital circuits, such as switching mode power supply. This kind of power circuits require accurate current sensor for power distribution. We studied characteristics of shunt resistor, which has many advantages for commercial application compared to Hall-effect current sensor. We applied ceramic package to the shunt resistor. Ceramic package has good thermal conductivity compared to plastic package, and this point is important for space requirement in Printed Circuit Board (PCB). Another advantage of the ceramic package is that surface mount technology (SMT) can be used for production. Our experimental results showed that the ceramic packaged resistor showed about 50% lower temperature than the plastic packaged one. Burning point and frequency characteristics are also discussed.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.23-26
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• 2015

A seam carving based micro-crack detection method is proposed which aims at detecting the micro-crack regions in heterogeneously textured surface of polycrystalline solar cells. By calculating the seam which is a connected path of low energy pixels in the image, the micro-crack regions can be detected. Experimental results show that the proposed seam carving based micro-crack detection method has superior efficiency in detecting the micro-crack without background noise pixels and the algorithm's computation time is less than the conventional algorithm.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.71-74
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• 2012

Uniformity of the wafer temperature is one of the important factors in etching process. Plasma, chucking force, backside helium pressure and the surface temperature of ESC(electrostatic chuck) affect the wafer temperature. ESC consists of several layers of structure. Each layer has own thermal resistance and the Si-adhesive layer has highest thermal resistance among them. In this work, the temperature distribution of ESC was analyzed by 3-D FEM with various defects and the thickness deviation of the Si-adhesive layer. The result with Si-adhesive layer with the low center thickness deviation shows modified temperature distribution of ESC surface.

• Journal of the Semiconductor & Display Technology
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• v.14 no.4
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• pp.78-83
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• 2015

The method of electrical discharge machining (EDM), one of the processing methods based on non-traditional manufacturing procedures, is gaining increased popularity, since it does not require cutting tools and allows machining involving hard, brittle, thin and complex geometry. Modern ED machinery is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, etc. This paper reports the results of an experimental investigation by Taguchi method carried out to study the effects of machining parameters on material surface roughness in electric discharge machining of SM45C. The work material was ED machined with graphite and copper electrodes by varying the pulsed current, voltage and pulse time. Investigations indicate that the surface roughness is strongly depend on pulsed current.