• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.195-202
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• 1998

The LPCVD system of batch type for the massproduction of semiconductor fabrication has a problem of phosphorous concentration uniformity in the boat. In this paper we study an improvement of the uniformity for phosphorous concentration and sheet resistance. These property was improved by using the nitrogen process and modified long nozzle for gas injection tube in the doped polysilicon deposition system. The phosphorous concentration and its uniformity for polysilicon film are measured by XRF(X-ray Fluorescence) for the conventional process condition and nitrogen process. In conventional process condition, the phosphorous concentration, it uniformity and sheet resistance for polysilicon film are in the range of 3.8~5.4$\times$10\ulcorner atoms/㎤, 17.3% and 59~$\Omega$/ , respectively. For the case of nitrogen process the corresponding measurements exhibited between 4.3~5.3$\times$10\ulcorner atoms/㎤, 10.6% and 58~81$\Omega$/ . We find that in the nitrogen process the uniformity of phosphorous concentration improved compared with conventional process condition, however, the sheet resistance in the up zone of the boat increased about 12 $\Omega$/ . In modified long nozzle, the phosphorous concentration, its uniformity and sheet resistance for polysilicon films are in the range of 4.5~5.1$\times$10\ulcorner atoms/㎤, 5.3% and 60~65$\Omega$/ respectively. Annealing after $N_2$process gives the increment of grain size and the decrement of roughness. Modification of nozzle gives the increment of injection amount of PH$_3$. Both of these suggestion result in the stable phosphorous concentration and sheet resistance. The results obtained in this study are also applicable to process control of batch type system for memory device fabrication.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.242-244
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• 2015

ZnO:Ga thin films were deposited by RF magnetron sputtering technique from ZnO (3 wt.% $Ga_2O_3$) target onto glass substrates under various RF power. The influence of RF power on the structural, electrical, and optical properties of ZnO:Ga thin films was investigated by X-ray diffraction, atomic force microscopy, Hall method and optical transmission spectroscopy. As the RF power increases from 50 to 110W, the crystallinity is deteriorated, the root main square surface roughness is decreased and the sheet resistance is increased. The increase of sheet resistance is caused by decreasing carrier concentration due to interstitial Ga ion. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is a red-shift with increasing RF power.

• Applied Science and Convergence Technology
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• 제26권4호
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• pp.55-61
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• 2017

Graphene, with a carrier mobility achieving up to $140,000cm^2/Vs$ at room temperature, makes it an ideal material for application in semiconductor devices. However, when the metal comes in contact with the graphene sheet, an energy barrier forms at the metal-graphene interface, resulting in a drastic reduction of the carrier mobility of graphene. In this review, the various methods of forming metal-graphene covalent contacts to lower the contact resistance are discussed. Furthermore, the graphene sheet in the area of metal contact can be cut in certain patterns, also discussed in this review, which provides a more efficient approach to forming covalent contacts, ultimately reducing the contact resistance for the realization of high-performance graphene devices.

• 한국정밀공학회지
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• 제22권2호
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• pp.133-138
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• 2005

The deformation of sheet metal due to the residual stress during blanking or piercing process, is numerically simulated by means of a commercial finite element code. Two dimensional plain strain problem is solved and then its result is applied to the deformation analysis of the lead frame. The plain strain element is applied to the 2D problem to observe the Von Mises equivalent stress concentration at the both shearing edges. As the punch penetrates into the sheet material, the stress concentration generated on both edges is getting increased to be the shearing surface. The limits of the punching depth applied to the simulation is 16% and 24% of the sheet thickness for the plain strain element and the hexahedral element, respectively. The hexahedral element and the limit of punching depth were applied to the deformation analysis of the lead frame for the blanking process. The FEM results for the lead deformation were very good agreement with the experimental ones. This paper shows that the coarse mesh has enabled to analyze the lead deformation generated due to the blanking mechanism. This simple approach to save the calculation time will be very effective to the design of the blanking tools in industries.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1561-1563
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• 2004

In this paper, we researched the dielectric properties and voltage dependence on slice XLPE sheet from 22[kV] and 154[kV] power cable. We studied effects for impurities and water for semiconductor shield through a dielectric properties experiment to estimate performance of insulating materials in power cable. Capacitance and tan${\delta}$ of 22[kV], 154[kV] were 53/43[pF] and $7.4{\times}10^{-4},\;2.1510^{-4}$. In these results, the trend was increased with the increase of temperature. The tan${\delta}$ of XLPF/ semiconductor layer was increased as compared with that of XLPE. Dielectric properties reliability of tan${\delta}$ was small.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.51-55
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• 2006

ITO/Ag/AZO and AZ0/Ag/ITO multi-layer films deposited on glass substrate by RF magnetron sputtering have a much better electrical properties than ITO and AZO single-layer films. The multi-layer structure was consisted of three layers of ITO, Ag and AZO. The optimum working pressure of AZO layers deposition was determined to be $1.0{\times}10^{-2}$ torr for high optical transmittance and good electrical conductivity. The electrical and optical properties of sub/IT0/Ag/AZO were higher than those of sub/AZ0/Ag/ITO multi-layer films.

• 소성∙가공
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• 제23권4호
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• pp.206-210
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• 2014

The metal lead frame, a semiconductor component, has product tolerances in micro units as compared to products made with a larger size mold. Therefore, small deflections of the mold and of the press as well as the press molding process itself have a strong influence on accuracy of the product. Hence, it is necessary for the process design to consider the structural response of the mold and the press during deformation. In the current study, the mold deflection and pressure on the punch is examined using the finite element modeling (FEM) program ABAQUS. The results from the simulation were verified with the dynamic deformation measurement equipment using digital image correlation (DIC).

• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.51-55
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• 2014

Ni-CNT(Carbon Nanotubes) composite coating is often used for the surface treatment of mechanical/electronic devices to improve the properties of the Ni coating. For the Ni-CNT coating, the dispersion of CNT fibers is a critical process. In this study, ultrasonic treatment instead of the conventional ball milling was attempted as a dispersion method for the electroless Ni-CNT coating. SEM-EDX analysis was performed and contact angle, sheet resistance, and micro-hardness were measured. Results showed that the ultrasonic treatment was comparable to the ball milling, as a dispersion method, but the difference was negligible. However, combined ball milling and ultrasonic treatment(double treatment) showed much improved micro-hardness value, above 350Hv(close to the value obtained by the Ni-CNT electroplating). In addition, electroless Ni-CNT(double-treated) coatings formed on the thin Ni film deposited by the electroless plating(double coating) showed better mechanical properties. Thus, double treatment and double coating are suggested as an improved electroless Ni-CNT coating method.

• 반도체디스플레이기술학회지
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• 제16권1호
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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.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.93-99
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• 2019

It is a wine recommendation application service designed for people who sometimes drink wine but lack information and have no place to recommend. This study is to develop UI display design method of wine recommendation service using chatbot. The research method was a case study on Korean wine market, a case study on artificial intelligence market, SWOT analysis of wine-related chatbots, and a competitor analysis of related industries. In addition, surveys and in-depth interviews examined the level of interest and understanding of chatbots, and what kind of chatbots they had encountered and what requirements and goals they faced. After grasping the needs and requirements of users, we created a service concept sheet according to them and produced an application UI design that users can use most easily. Therefore, this study is meaningful in that it proposes a UI design that can search wine information more sophisticated and convenient than face-to-face communication through artificial intelligence service called chatbot and recommend wines that match the taste.