• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.200.1-200.1
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• 2013

실리콘 태양전지 표면에는 구조적인 결함에 의해 소수 캐리어의 재결합이 일어난다. 재결합에 의해 캐리어의 반송자 수명은 줄어들게 되고, 태양전지의 효율은 감소하게 된다. 이를 줄이기 위해 태양전지 전 후면에 패시베이션을 하게 되는데, 이번 연구는 단결정 실리콘 태양전지 전면에 SiNx막을 증착함으로 수소 패시베이션이 반송자 수명에 미치는 영향에 대하여 연구하였다. 공정을 위해 $156{\times}156mm^2$, 200 ${\mu}m$, 0.5-3.0 ${\Omega}{\cdot}cm$ and p-type 단결정 실리콘 웨이퍼를 사용하였고, SiNx막을 올리기 전에 KOH 8.5% 용액으로 SDR을 실행하였다. RF-PECVD 장비로 SiNx 막을 증착하였고 증착 온도는 $200{\sim}400^{\circ}C$, 반응기 내부의 압력을 200~1,000 mtorr, SiH4/NH3/N2 각각의 가스 비율 조절, 그리고 플라즈마 RF power 변화시킴에 따라 증착된 SiNx막의 균일도 및 특성을 분석하였다. 반사광 측정 장비인 Reflectometer장비로 막의 두께와 굴절률, 반사율을 측정하였고, 반송자 수명을 측정하여 태양전지의 표면결함을 최대한 패시베이션 시켜주는 조건에 대한 연구를 수행하였다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.10
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• pp.78-88
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• 1995

For producing iron or steel products with good quality, the concentration of the material components should be analyzed quickly with high relability using XRF(Fluorescent X-Ray Spectrometer). Since the analysis results are much dependent upon the surface con- dition, the samples have to be prepared to have good test condition. This study presents an image processing system for inspecting the surface condition of the iron test sample. In order to use thd computer vision system, we need to develop a lighting device and image processing algorithm. For the adequate lighting device of inspection system, the indirect lighting device is contrived to cut the external light and provide uniform, stable and cold light. The image processing algorithm is aimed to reduce inspection time and to get similar analyzing results to those of the experienced operators. At first, the image processing algorithm checks whether the surface of the iron sample is ground well or not. Then, the defects; hole or dig are conted and surface condition is evaluated. In addition, the algorithm gives the reliability of the analyzing results in order to help operator's decision.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.499-504
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• 2010

Korean traditional buildings, Hanok, are mostly constructed with dimension lumbers and roundwoods. They are hardly kiln-dried without severe defects, thus usually air-dried from some months to an year. Dimension lumbers and roundwoods were heat-treated above $170^{\circ}C$ and drying defects were examined. Temperature rising curves of all dimension timbers used for this study show one or two deflection points. The time when the temperature at 37.5mm depth reached at $100^{\circ}C$ for spruce dimension heat-treated at $170^{\circ}C$ was twice longer than that heat-treated at $190^{\circ}C$. There were many internal checks in roundwoods of $148mm{\Phi}$, while surface checks were apparently closed at the end of heat treatment. The drying time of $300{\times}300mm$ dimensions with 65mm hole was shorter than that without hole by half.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1461_1462
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• 2009

송전선로에 설취된 애자들은 지속적인 전기적 기계적 스트레스에 노출되어 있기 때문에 여러 환경적 요인으로 인해 애자 표면의 열화가 가속된다. 이와 같은 애자의 표면 열화는 dryband를 형성하게 되고 지속적인 애자 표면상의 dryband와 누설 전류 증가의 상호작용은 애자의 섬락를 일으키는 원인이 된다. 이러한 연구의 결과 고전압용 애자로 유입되는 누설 전류는 애자 열화의 정도를 평가할 수 있는 매우 중요한 parameter임을 알 수 있다. 따라서 고전압용 애자의 누설전류를 분석하고 취득하여 애자의 열화 평가 및 이로 인해 발생할 수 있는 결함 애자의 검출에 대한 연구가 절실히 요구되고 있다. 본 논문에서는 고전압용 애자 중 자기애자의 습도변화에 따른 누설전류 특성을 조사하기 위해 자체 제작한 실험 챔버, power transformer, 전류센서, 오실로스코프, PC등으로 구성된 실험 시스템을 구축하였고, 데이터 분석을 위한 S/W로서 LabView를 사용하였다. 그에 따른 실험결과로서 다양한 습도변화(30%~90%)의 경우 정상 애자련과 결함 애자를 포함한 애자련의 누설전류 데이터를 취득하여 본 연구에서 제시한 알고리즘을 통해 분석함으로써 정상 애자 내의 결함 애자 포함 여부를 판별하고 다양한 습도 변화시에 정상 애자련과 불량 애자련의 특징을 볼 수 있었다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.29-35
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• 2015

The photo-response characteristics of polysilicon based metal-semiconductor-metal (MSM) photodetector structure, depending on deuterium treatment method, was analyzed by means of the dark-current and the light-current measurements. Al/Ti bilayer was used as a Schottky metal. Our purpose is to incorporate the deuterium atoms into the absorption layer of undoped polysilicon, effectively, for the defect passivation. We have introduced two deuterium treatment methods, a furnace annealing and an ion implantation. In deuterium furnace annealing, deuterium bond was distributed around polysilicon surface where the light current flows. As for the ion implantation, even thought it was a convenient method to locate the deuterium inside the polysilicon film, it creates some damages around polysilicon surface. This deteriorated the photo-response in our photodetector structure.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.1
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• pp.8-11
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• 2012

Automated Vision Inspection (AVI) systems automatically detect any defect feature in a surface image. The performance of the system can be measured under a special circumstances such as ultimate defect detection. In this situation, the defect signal level is similar to noise level and it becomes hard to make a solid decision with AVI systems. In this paper, we propose an effective preprocessing technique to enhance SNR (Signal to Noise Ratio). The method is motivated by some principles of HVS (Human Visual System) and RLC (Run Length Coding) techniques is used for this purpose. The proposed preprocessing technique enhances SNR under ultimate defect conditions and improves overall performance of AVI system.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.6
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• pp.445-454
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• 1998

In order to establish a technical concept for the detection of defects in weldments in thin steel plate, an experimental and theoretical investigation was carried out for artificial defects in a steel plate having a thickness of 2.4mm by using the guided wave technique. In particular the goal was to find the most effective testing parameters paying attention to the relationship between the excitation frequency by a tone burst system and various incident angles. It was found that the test conditions that worked best was for a frequency of 840kHz and an incident angle of 30 or 85 degrees, most of the defects were detected with these conditions. Also, it was clear that a guided wave mode generated under an incident angle of 30 degrees was a symmetric mode, So, and that of 85 degrees corresponded to an antisymmetric mode, Ao. By using the two modes, most of all of the defects could be detected. Furthermore, it was shown that the antisymmetric mode was more sensitive to defects near the surface than the symmetric mode. Theoretical predictions confirmed this sensitivity improvement with Ao for surface defects because of wave structure variation and energy concentration near the surface.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.1
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• pp.33-40
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• 1992

Several etching phenomena were observed and analyzed in diaphragm process performed on 4-inch (100) Si wafers for sensor application. In case of deep etching to above 300$\mu$m depth, the etch-defects appeared at etched surface could be classified into three categories such as hillocks, reaction products, and white residues. It was known that the hillock had a pyramidal shape or trapizoidal hexahedron structure depending on the density and size of the reaction products. The IR spectra showed that the white residue, which was due to the local over-saturation of Si dissolved in solution, was mostly Si-N-O compounds mixed with a small amount of H and C etc. Also, the difference in both the existence of etch-defects and etch rate distribution over a whole wafer was investigated when the etched surfaces were downward, upward horizontally and erective in etching solutions. The obtained data were analyzed through flow pattern in the etching bath. As the results, the downward and erective postures were favorable in the etch rate uniformity and the etch-defect removal, respectively.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.75-80
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• 2003

In this paper, we designed add current scan system basically. Although NDT system using AC method in now days had problem with limit of detection rate and limit of device organization, in this paper, we made up these problem so that designed device smaller than system used, reduction of cost of system organization and precision of measuring crack. Also, AC leakage flux system had high accuracy about minute crack in the surface and advantage of designing system easily so that we designed system for concerning about crack of surface. Furthermore, it can be able to detect exact crack of reference in wide area by using DSP320C31 chip to reduce the time of measuring crack.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.145-153
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• 2009

The purpose of this research is to propose a system to detect a strip defect on a iron plate using an image processing, one way of finding defects on an iron plate. An existing way of image processing is using a light source which release a light energy in a certain frequency and a light absorbing display which responds to the light source. This research attempts to detect defects by using a image processing and multi-Tread which handles an illumination, without depending on characteristics of light frequency. One of the advantages of this method is that it makes up for the weakness of the existing method which was too difficult for users to notice a defect. Also this method makes it possible to realize a real-time monitoring on a plate of iron. The other advantage of this method is that it reduces the price of hardwares on demand to match the frequency of light emitting display and light absorbing display because this method only needs a hardware which is easy to buy in any market.