• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.104-104
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• 2005

• Journal of Sensor Science and Technology
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• v.10 no.4
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• pp.207-213
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• 2001

A Schottky type GaN ultraviolet photodetector with a mesa structure was fabricated by depositing an Al ohmic contact on an $n^+$-GaN layer and a Pt Schottky contact on a GaN layer. The undoped GaN(0.5um)/$n^-$-GaN(0.1 um)/$n^+$-GaN(1.5 um) multi-layer structure was grown on a sapphire substrate using MOCVD. The Schottky contact properties were characterized for different passivation conditions. The leakage current of the fabricated Schottky diode was 2 nA at a reverse voltage of 5V. Plus the photocurrent was 120uA using a hydrargyrum lamp with an optical power of 1mW at a wavelength of 365 nm. The diode exhibited an ultraviolet-visible rejection ratio of $10^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.334-337
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• 2002

The Quantum Hall Resistance(QHR) device which consists of GaAs/AlGaAs heterojunction structure is used for the realization of QHR Standard based on QHE. In order to characterize electrical contact resistances and dissipations of the device, it is slowly cooled down for eliminating thermal shock and unwanted noise. Then, the two properties are measured under 1.5 K and 5.15 T. Contact resistances are all within 1.2 Ω and longitudinal resistivities are all within 1 mΩ up to DC 90${\mu}$A. The results mean the device is operated well to realize the QHR Standard. To confirm it, the QHR Standard having the device is compared using a direct current comparator bridge with a 1 Ω resistance standard which the calibrated value is known from QHR standards maintained by other countries. The difference between them is agreed well within measurement uncertainty. It is thus considered that the properties of the device is estimated well and has good performance.

• Journal of Applied Reliability
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• v.7 no.1
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• pp.23-29
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• 2007

Probe card is a test component which is to classify the known good die with electrical contact before the packaging in the ATE (automatic testing equipment). Conventional probe tip was mostly needle type, it has been difficult to meet with conventional type, because of decreasing chip size, pad to pad pitch and pads size increasingly. For that reason, probe cards using MEMS (micro electro mechanical system) technology have been developed for various semiconductor chips. In this paper, Area Array type MEMS Probe tip was designed,, fabricated, and characterized its mechanical and electrical properties. The authors found that good electrical characteristics under $1{\Omega}$ were acquired with gold (Au) and aluminium (Al) pad contact test over 0.5gf and 4gf respectively. And, contact resistance variation under $0.1{\Omega}$ were achieved with 100,000 times of repetition test. And, insertion loss (IS) for high frequency operation was ascertained over 300MHz at -3dB loss.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.225-228
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• 2017

In this study, zinc tin oxide (ZTO) films were prepared on indium tin oxide (ITO) glasses and annealed at different temperatures under vacuum to investigate the correlation between the Ohmic/Schottky contacts, electrical properties, and bonding structures with respect to the annealing temperatures. The ZTO film annealed at $150^{\circ}C$ exhibited an amorphous structure because of the electron-hole recombination effect, and the current of the ZTO film annealed at $150^{\circ}C$ was less than that of the other films because of the potential barrier effect at the Schottky contact. The drift current as charge carriers was similar to the leakage current in a transparent thin-film device, but the diffusion current related to the Schottky barrier leads to the decrease in the leakage current. The direction of the diffusion current was opposite to that of the drift current resulting in a two-fold enhancement of the cut-off effect of leakage drift current due to the diffusion current, and improved performance of the device with the Schottky barrier. Hence, the thin film with an amorphous structure easily becomes a Schottky contact.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.986-988
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• 2022

본 연구는 전기전자기기를 비접촉 ON/OFF제어와 기기의 수명연장을 개선 시키기위해 전기전자기기에 다용도로 활용되는 제어컨트롤러 모듈인 PLC(Programmable Logic Controller)의 입력측에 마이크로컨트롤러와 AI 비젼카메라를 설치하여, 비접촉 ON/OFF 제어에 관한 아이디어 제시하고, 이를 기반으로 구현하였다. 구현 결과 단순 I,O 신호에 의한 제어와는 다르게 이미지 인식을 구체적으로 구분하여 센싱하고, 다양한 인식 구분을 위해 머신러닝 기반으로 AI 비젼카메라를 학습시킨 결과 물체 및 색깔 구분에 따라서 전기전자기기를 제어 할 수 있었으며, 접촉이 아닌 비접촉 ON/OFF 제어가 간단하게 구현되어, 전기전자기기 수명연장도 기대 할 수 있게 되었다..

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.194-202
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• 1999

Various ways of designing heat sink are available for commercial high power converters and among them, the method of air cooling is the most popular and practical method than any other ones. In this paper, a practical method of cooling high power converter, which includes a method of reducing noise and vibration caused by the fan and a method of estimating the gap and contact resistances existing between the thyristor and heat sink, is presented. Finally, the heat transfer analysis and implementation methods of heat sink for high power converter is presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.373-373
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• 2007

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.36-37
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• 2016

The main cause of electrical fires are caused due to short circuit and open circuit. This is generates an instantaneous electric arc or spark accompanied with such electric faults. These arcs generate a pressed wire, contact badness, and a weakness in the wire coating etc.. This research proposes a protection circuit to prevent open-phase accident due to contact failure of electromagnetic contactor, tracking arc fault, open-phase within the three-phase electrical control panel which is the most commonly applied in the industry. The proposed circuit also alarms and cuts off of power system when electrical faults occurs. In addition, the proposed circuit is validated by various electric accident simulator.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.41-47
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• 2013

The electrical relay in an essential part of the Smart Grid, Electrical Vehicle (EV) and LED lightning system. For these reasons, research of electrical relay is actively underway. In this paper, analyze of the relationship between the bouncing of relay contact and magnetic flux of permanent magnet. Experiment result, changes the bouncing numbers depending on the magnetic flux of the latching relay. And find the value of the magnetic flux that occurs to minimize the bouncing of the contacts. In additions, by the increasing the magnetic flux, unconditional bounce is not reduced. The bouncing number of latching relay is less than expected the armature relay for present results. Further experiments are need to prove it, bouncing on the armature relays.