• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.40-41
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• 2006

본 논문은 수직형 트랜치 IGBT 구조에서 에미터를 트랜치로 형성하여 그 전기적인 특성을 MEDICI를 이용하여 고찰하였다. 제안한 구조의 항복전압과 온-상태 전압, 래치업 전류 그리고 턴-오프 시간이 기존 트랜치 IGBT에 비하여 향상되었음을 알 수 있었다. 항복전압은 트랜치 에미터에 의해 트랜치 게이트에 집중되는 전계를 완화시켜 일반적인 트랜치 IGBT보다 19%정도 향상되었으며 온-상태 전압과 래치업 전류는 각각 25%, 16% 정도 향상되었다. 하지만 제안된 구조의 턴-오프 시간은 무시할 수 있을 정도로 약간 증가하였음을 알 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.22-27
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• 2008

Analytical models for breakdown voltage and specific on-resistance of 4H-silicon carbide Schottky diodes have been derived successfully by extracting an effective ionization coefficient $\gamma$ from ionization coefficients $\alpha$ and $\beta$ for electron and hole in 4H-SiC. The breakdown voltages extracted from our analytical model are compared with experimental results. The specific on-resistance as a function of doping concentration is also compared with the ones reported previously. Good fits with the experimental results are found for the breakdown voltage within 10% in error for the doping concentration in the range of about $10^{15}{\sim}10^{18}\;cm^{-3}$. The analytical results show good agreement with the experimental data for the specific on-resistance in the range of $3{\times}10^{15}{\sim}2{\times}10^{16}\;cm^{-3}$.

• Journal of IKEEE
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• v.22 no.4
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• pp.916-921
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• 2018

In this paper, we analyzed the power MOSFET devices for high voltage and high current operation. 4H-SiC was used instead of Si to improve the static characteristics of the device. Since 4H-SiC has a high critical electric field due to wide band gap, 4H-SiC is more advantageous than Si in high voltage and high current operation. In the conventional VDMOSFET structure using 4H-SiC, the breakdown voltage is limited due to the electric field crowding at the edge of the p-base region. Therefore, in this paper, we propose a Curvature VDMOSFET structure that improves the breakdown voltage and the static characteristics by reducing the electric field crowding by giving curvature to the edge of the p-base region. The static characteristics of conventional VDMOSFET and curvature VDMOSFET are compared and analyzed through TCAD simulation. The Curvature VDMOSFET has a breakdown voltage of 68.6% higher than that of the conventional structure without increasing on-resistance.

• Journal of IKEEE
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• v.19 no.4
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• pp.491-499
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• 2015

Silicon Carbide(SiC) has large advantage in high temperature and high voltage applications because of its high thermal conductivity and large band gap energy. When using SiC to design power semiconductor devices, edge termination techniques have to be adjusted for its maximum breakdown voltage characteristics. Many edge termination techniques have been proposed, and the most appropriate technique for SiC device is Junction Termination Extension(JTE). In this paper, the change of breakdown voltage efficiency ratio according to the change of doping concentration and passivation oxide charge of each JTE techniques is demonstrated. As a result, the maximum breakdown voltage ratio of Single Zone JTE(SZ-JTE), Double Zone JTE(DZ-JTE), Multiple Floating Zone JTE(MFZ-JTE), and Space Modulated JTE(SM-JTE) is 98.24%, 99.02%, 98.98%, 99.22% each. MFZ-JTE has the smallest and SZ-JTE has the largest sensitivity of breakdown voltage ratios according to the change of JTE doping concentration. Additionally the degradation of breakdown voltage due to the passivation oxide charge is analyzed, and the sensitivity is largest in SZ-JTE and smallest in MFZ-JTE, too. In this paper, DZ-JTE and SM-JTE is the best efficiency JTE techniques than MFZ-JTE which needs large doping concentration in short JTE width.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.377-380
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• 2003

An Analytic breakdown voltage model of LDMOS with internal field ring is proposed. The model is a simple analytic formula which has variables such as the dimension of drift retion, the position and doping concentration of the internal field ring, the thickness and permittivity of oxide. By comparing the results from two dimensional TCAD simulation, the proposed model explains the breakdown phenomena fairly well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1175-1179
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• 2009

We analyze voltage characteristics of charged particle type display according to particle layers and cell gap between two electrodes and ascertain the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of charged particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for charged particle type display.

• Journal of Digital Contents Society
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• v.18 no.6
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• pp.1193-1198
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• 2017

The IGBT structure developed in this paper is used as a high power switch semiconductor for DC transmission and distribution and it is expected that it will be used as an important electronic device for new and long distance DC transmission in the future by securing fast switching speed and improved breakdown voltage characteristic. As a new type of next generation power semiconductors, it is designed to improve the switching speed while at the same time improving the breakdown voltage characteristics, reducing power loss characteristics, and achieving high current density advantages at the same time. These improved properties were obtained by further introducing SiO2 into the N-drift region of the Planar IGBT and were compared and analyzed using the Sentaurus TCAD simulation tool.

• Journal of IKEEE
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• v.11 no.4
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• pp.235-238
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• 2007

The planar edge termination techniques of field-ring and deep junction field-ring were investigated and optimized using a two-dimensional device simulator TMA MEDICI. By trenching the field ring site which would be implanted, a better blocking capability can be obtained. The results show that the p-n junction with deep junction field-ring can accomplish near 30% increase of breakdown voltage in comparison with the conventional field-rings. The deep junctionfield-rings are easy to design and fabricate and consume same area but they are relatively sensitive to surface charge. Extensive device simulations as well as qualitative analyses confirm these conclusions.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.1-5
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• 2009

Analytical expressions for breakdown voltage and specific on-resistance of 6H-SiC PN diodes have been derived successfully by extracting an effective ionization coefficient from ionization coefficients for electron and hole in 6H-SiC. The breakdown voltages induced from our analytical model are compared with experimental results. The variation of specific on-resistance as a function of doping concentration is also compared with the one reported previously. Good fits with experimental results are found for the breakdown voltage within 10% in error for the doping concentration in the range of $10^{15}{\sim}10^{18}cm^{-3}$. The analytic results show good agreement with the numerical data for the specific on-resistance in the region of $5{\times}10^{15}{\sim}10^{16}cm^{-3}$.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1406-1407
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• 2006

본 논문에서는 기존의 250V급 트렌치 전극형 파워 MOSFET을 구조적으로 개선하여, 600V 이상의 순방향 항복 전압을 갖는 파워 MOSFET을 설계 하였다. 본 논문에서 제안한 구조로 기존의 250V급 트렌치 전극형 파워 MOSFET에 비하여 더욱 높은 순방향 항복 전압을 얻었다. 또한, 기존의 LDMOS 구조로 500V 이상의 항복 전압을 얻기 위해서 $100{\mu}m$ 이상의 크기를 필요로 했던 반면에, 본 논문에서 제안한 소자의 크기(vertical 크기)는 $50{\mu}m$로서, 소자의 소형화 및 고효율화 측면에서 더욱 우수한 특성을 얻었다. 본 논문은 2-D 공정시뮬레이터 및 소자 시뮬레이터를 바탕으로, 트렌치 옥사이드의 두께 및 폭, 에피층의 두께 변화 등의 설계변수와 이온주입 도즈 및 열처리 시간에 따른 공정변수에 대한 시뮬레이션을 수행하여, 본 논문에서 제안한 구조가 타당함을 입증하였다.