• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.865-873
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• 2017

Converter transformer is the key equipment of high voltage direct current transmission system. The solid suspending particles originating from the process of installation and operation of converter transformer have significant influence on the insulation performance of transformer oil, especially in presence of DC component in applied voltage. Under high electric field, the particles easily lead to partial discharge and breakdown of insulating oil. This paper investigated copper particle effect on the breakdown voltage of transformer oil at combined AC and DC voltage. A simulation model with single copper particle was established to interpret the particle effect on the breakdown strength of insulating oil. The experimental and simulation results showed that the particles distort the electric field. The breakdown voltage of insulating oil contaminated with copper particle decreases with the increase of particle number, and the breakdown voltage and the logarithm of particle number approximately satisfy the linear relationship. With the increase of the DC component in applied voltage, the breakdown voltage of contaminated insulating oil decreases. The simulation results show that the particle collides with the electrode more frequently with more DC component contained in the applied voltage, which will trigger more discharge and decrease the breakdown voltage of insulating oil.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.813-816
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• 2003

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, according to Weibull distribution analysis, reducing breakdown probability of equipment insulation lower than 0.1 % level requires the allowable field intensity values to be kept under 21.5 MV/cm.

• 대한전기학회논문지
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• 제44권4호
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• pp.490-495
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• 1995

A bipolar junction transistor which exihibits 1000V breakdown voltage is designed and fabricated using FLR (Field Limiting Rings). Three dimensional effects on the breakdown voltage is investigated in the cylindrical coordinate and the simulation results are compared with the results in the rectangular coordinate. Breakdown voltage of the device with 3 FLR is simulated to be 1420V in the cylindrical coordinate while it is 1580V in rectangular coordinate. Bipolar junction transistor has been fabricated using the epitaxial wafer of which resistivity is 86 .OMEGA.cm and thickness is 105 .mu.m. Si$_{3}$N$_{4}$ and glass are employed for the passivation. Breakdown of the fabricated device is measured to be 1442V which shows better greement with the simulation results in cylindrical coordination.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권6호
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• pp.300-304
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• 2004

We have proposed the junction termination design employing shallow trench filled with silicon dioxide and field limiting ring (FLR). We have designed trenches between P+ FLRs to decrease the junction termination radius without sacrificing the breakdown voltage characteristics. We have successfully fabricated and measured improved breakdown voltage characteristics of the Proposed device for 1200 V-class applications. The junction termination radius of the proposed device has decreased by 15%-21% compared with that of the conventional FLR at the identical breakdown voltage. The junction termination area of the proposed device has decreased by 37.5% compared with that of the conventional FLR. The breakdown voltage of the proposed device employing 7 trenches was 1156 V, which was 80% of the ideal parallel-plane .junction breakdown voltage.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.187-191
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• 2001

In this paper, the ac breakdown characteristics of Ar/$N_2$and Kr/$N_2$gas mixtures with gas pressure range of 58.8~137.3[kPa] under uniform and non-uniform fields were investigated. Summarizing the experimental results, the breakdown voltages of Ar/$N_2$ gas mixtures were decreased with decreasing the mixture ratio of pure $N_2$gas. In case of Ar(85%)/$N_2$(15%) and Ar(70%)/$N_2$(30%) gas mixtures comparing to the pure Ar gas, the breakdown voltages under uniform field were increased about 1.8 and 2.2 times, and under non-uniform field were increased about 1.1 and 1.3 times at the pressure of 101.3[kPa]. Also, in case of Kr(85%)/$N_2$(15%) and Kr(70%)/$N_2$(30%) gas mixtures comparing to the pure Kr gas, the breakdown voltages under uniform field were increased about 1.7 and 2.0 times, and under non-uniform field were increased about 1.0 and 1.2 times.

• 대한전자공학회논문지SD
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• 제48권12호
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• pp.8-14
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• 2011

본 논문에서는 이차원 소자 시뮬레이션을 활용하여 주어진 게이트-드레인 간격에서 AlGaN/GaN-on-Si HEMT (high electron mobility transistor) 의 고항복전압 구현을 위한 게이트 전계판의 최적화 구조를 제안하였다. 게이트 전계판 구조를 도입하여 게이트 모서리의 전계를 감소시켜 항복전압을 크게 증가시킬 수 있음을 확인 하였으며, 이때 전계판의 길이와 절연막의 두께에 따라 게이트 모서리와 전계판 끝단에서 전계분포의 변화를 분석하였다. 최적화를 위하여 시뮬레이션을 수행한 결과, 1 ${\mu}m$ 정도의 짧은 게이트 전계판으로도 효과적으로 게이트 모서리의 전계를 감소시킬 수 있으며 전계판의 길이가 너무 길어지면 전계판과 드레인 사이의 남은 길이가 일정 수준 이하로 감소되어 오히려 항복전압이 급격하게 감소함을 보였다. 전 계판의 길이가 1 ${\mu}m$ 일 때 최대 항복전압을 얻었으며, 게이트 전계판의 길이를 1 ${\mu}m$로 고정하고 $SiN_x$ 박막의 두께를 변화시켜본 결과 게이트 모서리와 전계판 끝단에서의 전계가 균형을 이루면서 항복전압을 최대로 할 수 있는 최적의 $SiN_x$ 박막 두께는 200~300 nm 인 것으로 나타났다.

• 한국정보통신학회논문지
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• 제8권8호
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• pp.1719-1724
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• 2004

본 논문에서는 차세대 RF 전력 소자로 기대하고 있는 LDMOST의 BV(Breakdown; 항복전압) 특성을 향상시키는 새로운 구조를 제안하였다. 제안한 구조는 외부 전계 링이라 하며 드리프트 영역 둘레에 3차원적인 구조로 형성된다. 외부 전계 링은 드리프트 영역에서 전계를 완화시키는 역할을 함으로써 BV 특성을 향상시키는 효과를 얻을 수 있다. 3차원 TCAD 시뮬레이션 결과, 외부 전계 링의 접합깊이와 도핑 농도의 증가에 따라 LDMOST의 BV가 증가함을 확인할 수 있었다. 따라서 기존의 p+ sinker 공정을 사용하여 외부 전계 링 구조를 추가한다면 LDMOST의 BV 특성을 크게 향상 시킬 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.155-158
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• 1988

The fabrication of devices using plans technology could lend to n serious degradation in the breakdown voltage as a result of high electric field at the edges. An elegant approach to reducing the electric field at the edge is by using field limiting ring. The presence of surface charge has n strong influrence on the depletion layer spreading at the surface region because this charge complements the charge due to the ionized acceptors inside the depletion layer. Surface charge of either polarity can lower the breakdown voltage because it affects the distribution of electric field st the edges. In this paper we discuss the influrences of fixed oxide charge on the breakdown voltage of the p+/n junction with field limiting ring(or without field limiting ring).

• 한국전기전자재료학회논문지
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• 제28권9호
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• pp.551-554
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• 2015

This paper was analyzed electrical characteristics of super junction IGBT with super junction field rings. As a result of super junction IGBT with super junction field rings, we obtained 3,300 V breakdown voltage and good thermal characteristics. we obtained shrinked chip size because field ring was decreased than field ring for conventional IGBT, too. And we fabricated super junction IGBT with super junction field rings. As a result of measuring fabricated chip, we obtained 3,300 V breakdown voltage. The fabricated devices were replaced thyristos using high voltage conversion, sufficiently.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.232.2-232.2
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• 2013

본 연구에서는 asymmetric과 symmetric MOSFET 소자의 drain breakdown 및 snapback 특성을 분석하였다. 실험에서는 두 MOSFET 소자의 동작 영역에서 게이트와 드레인에 각각 전압을 인가하였다. 드레인 전류-전압 곡선으로 부터 drain breakdown 전압과 snapback 전압을 추출하였다. 결과 avalanche breakdown 발생 전의 드레인 전류는 asymmetric 구조의 경우 더 작은 값을 보였으며 이는 asymmetric 구조에서의 drain field 가 더 낮기 때문이다. 따라서 impact ionization은 asymmetric 구조에서 덜 발생하며, snapback 전압은 avalanche breakdown voltage가 작은 asymmetric 구조에서 크게 나타났다.