• Applied Science and Convergence Technology
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• v.27 no.2
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• pp.23-25
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• 2018

With respect to the electrode structure and the discharge characteristics, the atmospheric pressure plasma sheet of a thin polyimide film is introduced in this study; here, the flexible plasma device of a dielectric-barrier discharge with the ground electrode and the high-voltage electrode formulated on each surface of a polyimide film whose thickness is approximately $100{\mu}m$, that is operated with a sinusoidal voltage at a frequency of 25 kHz and a low voltage from 1 kV to 2 kV is used. The streamer discharge is appeared along the cross-sectional boundary line between two electrodes at the ignition stage, and the plasma is diffused on the dielectric-layer surface over the high-voltage electrode. In the development of a plasma sheet with thin dielectric films, the avoidance of the insulation breakdown and the reduction of the leakage current have a direct influence on the low-voltage operation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.244-245
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• 2015

PEALD TiN 금속 전극을 갖는 MOS device에서 SC1 ($NH_4/H_2O_2/H_2O=1:2:5$), SPM ($H_2SO_4/H_2O_2=10:1$), $H_2O_2$ etch chemical을 이용해 TiN 식각 후 oxide 표면 잔류 Ti에 의한 전기적 특성 분석을 진행 하였다. Etch chemical 중 SPM을 이용한 소자의 전기적 특성이 우수하였는데, 이는 잔류Ti atom의 양이 다른 etch chemical을 사용한 것 대비 낮았기 때문이다. 이로 인하여 낮은 leakage current, less frequency dependence의 특성이 관찰되었다. 또한, 후속 열처리를 통해 더욱 우수한 특성이 관찰 되었다. 이러한 공정기술은 single 전극을 갖는 CMOS 형성 시 사용 될 수 있을 것으로 기대된다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.11
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• pp.550-556
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• 2001

The computerized cardiac analysis system, which acquires and analyzes the electrical activation signal propagating along the surface of the heart, is indispensible equipment for the open heart surgery and electrical cardiac study. In this paper, the design requirement and the electrical circuit analysis are performed to construct the multi-channel cardiac activation pre-amplifier necessary for a signal conditioning circuit. The general 64 channel configuration is expanded into 128 channels to enhance the spatial resolution on the mapped surface of the heart. The 128 channels pre-amplifier consists of input circuit, differential amplifier, right leg driven circuit and isolation part. It has distinct features; high voltage protection, leakage current limitation, isolation and the maximization of common mode rejection ratio with respect to the half-cell potential difference due to different electrode materials. The final pre-amplifier circuit is assembled with 8 boards, each of which composing of 16 channels.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.306-310
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• 1996

In this paper a series of developing process for an insulator which can be employed in overhead distribution lines, using polymeric composite materials, is introduced. In order to design an insulator for heavily polluted area, weathershed of alternating type was adopted, which could have longer leakage distance. Modified EVA was used as surface material which has good electrical and mechanical characteristics as well as superior chemical stability. FRP core was covered with above surface material through heat shrinking process. By standardization of each process, higher productivity and lower production cost could be ensured. The developed insulator has been put under various tests including long-term field test and artificial aging test and satisfactory results were obtained.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.47-53
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• 2007

Ultra thin Si p-n junctions shallower than $300{\AA}$ were fabricated and biased to the avalanche regime. The ultra thin junctions were fabricated to be parallel to the surface and exposed to the surface without $SiO_2$ layer. Those junctions emitted white light and electrons when junctions were biased in the avalanche breakdown regime. Therefore, we could observe the avalanche breakdown region visually. We could also observe the influence of electric field to the current flow visually by observing the white light which correspond to the avalanche breakdown region. Arrayed diodes emit light and electrons uniformly at the diode area. But, the reverse leakage current were larger than those of ordinary diodes, and the breakdown voltage were less than 10V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.25-28
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• 1998

In this study, we investigated the electrical characteristics of silicone rubber that being used outdoor insulating material, which had been immersed in salt water. After immersed the sample in salt water, we measured surface hydrophobicity, weight loss and microscopic surface appearance, and then compared with these of the original. And we tested the electrical characteristics of the aged sample by the water under salt-fog. These electrical characteristics are described by the average of leakage current, peak pulse number, which are recorded by data acquisition system The experimental results show that the resistance against tracking and erosion is decreased significantly by water penetration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.767-770
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• 2000

This study was investigated for searching a cause of flashover failure of polymer insulator and preparing countermeasures. Hydrophobicity, microstructure and chemical structural change of polymer weathershed were studied by polymer characterization methods. In addition, the electrical properties such as power frequency dry flashover voltage/impulse voltage tests, contamination characteristics were carried out. The hydrophobicity of polymer weathershed was decreased significantly and cracks were observed on the surface. Also, the electrical characteristics did not satisfy the KEPCO specification. The failed polymer insulators showed the more leakage current than 4 years service-aged ones. From the result, it can be concluded that the flashover failure of polymer insulator was attributed to the surface aging and severe contamination.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.131-132
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• 2007

An AlGaN/GaN high electron mobility transistor(HEMT) was fabricated and the effect of photoelectrochemical oxidation of AlGaN/GaN surface was investigated. The oxidation of AlGaN surface was done in water at the bias of 10 V under the deep UV light illumination. The sheet resistance of the AlGaN/GaN structure was increased and gate leakage current of the HEMT was decreased by the oxidation. However, the transconductance of the HEMT was not degraded by the oxidation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.417-420
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• 2004

The electrical effects of dry-etch on n-type GaN by an inductively coupled $Cl_2/CH_4/H_2/Ar$ plasma were investigated as a function of ion energy, by means of ohmic and Schottky metallization method. The specific contact resistivity(${\rho}_c$) of ohmic contact was decreased, while the leakage current in Schottky diode was increased with increasing ion energy due to the preferential sputtering of nitrogen. At a higher rf power, an additional effect of damage was found on the etched sample, which was sensitive to the dopant concentration in terms of the ${\rho}_c$ of ohmic contact. This was attributed to the effects such as the formation of deep acceptor as well as the electron-enriched surface layer within the depletion layer. Furthermore, thermal annealing process enhanced the ohmic and Schottky property of heavily damaged surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.558-559
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• 2005

Recently, polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. In this paper, the tracking property of polymer suspension insulator for power transmission is investigated with CEA tracking wheel test. The diagnosis of insulator sample in tracking test has been analyzed by leakage current, STRI Guide, SEM, FTIR and thermal image.