• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.190-193
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• 2010

Various power semiconductor devices have been developed and evolved since 1950s. Among them, IGBT is the most developed power semiconductor device which has high breakdown voltage, high current conduction and suitable switching speed which perform trade-offs between each other. In other words, there are trade-offs between a breakdown voltage and on-state voltage drop, and between on-state voltage drop and turn-off time. In this paper, the new structure is proposed to improve a trade-off between a breakdown voltage and on-state voltage drop. The proposed structure has a trench collector and this trench collector induces an accumulation layer at the bottom of an n-drift region during off-state. And this accumulation layer prevents expansion of depletion layer so that trapezoidal electric field distribution is performed in the n-drift region. As a result of this, breakdown voltage is increased without increasing on-state voltage drop. The electrical characteristics of the proposed IGBT is analyzed and optimized by using representative device simulator, TSUPREM4 and MEDICI. After optimization, the electrical characteristics of the proposed IGBT is compared with NPT IGBT which have the same device thickness. As a result of this, it can be confirmed that the proposed structure increases the breakdown voltage of 800 V than that of the conventional NPT IGBT without increasing the on-state voltage drop.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.133-138
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• 2022

In previous studies to obtain the residual magnetic flux of the transformer using the leakage magnetic flux, a transfer function was used. The transfer function was consisted with the leakage magnetic flux measured outside the transformer and the residual magnetic flux measured at the moment passing through the two ± residual points. In this study, a method of calculating the ratio of the maximum operating leakage flux to the residual leakage flux was proposed The advantage of this method is to avoid the uncertainty of the transfer function due to current noise. Then, the noise of the sensor was measured to investigate the effect of the drift of the noise on the measurement results. Comparing the residual leakage magnetic flux density with 80nT of the drift noise, 66 times or more at a distance of 10 mm and 5 times or more at a distance of 100 mm were obtained. 100mm was the maximum measurement distance to obtain the residual magnetic flux.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1544-1545
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• 2011

For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. Processing plasma etching of semiconductor, and research are being used in the etching source $C_4F_6$ gas may be used by itself and mixed with other gases are also used. However, the molecular gas $C_4F_6$ study on the characteristics of the electron transport and the cross-sectional area of the decision is still lacking. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients. And to understand and interpret physical properties of the ionization coefficient ${\alpha}$/N, and the attachment coefficient ${\eta}$/N in $C_4F_6$ gas.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1540-1541
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• 2011

We calculated the electron transport coefficients in $H_2$+Ar gas calculated E/N values 0.01 ~ 1 Td by the Boltzmann equation method. This study gained the values of the electron swarm parameters such as the electron drift velocity and the transverse diffusion coefficients for $H_2$+Ar gas at a range of E/N. The transport coefficient W and Dt/u have been calculated in mixtures of 0.5% and 4% hydrogen in argon. All values were made at 293 K.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.342-345
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• 2005

This paper describes the electron energy distribution function characteristics in $SF_6-He$ gas calculated for range of E/N values from $50{\sim}700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N. The results of Boltzmann equation and Monte carlo simulation have been compared with experimental data by Pollock, Ohmori, cottrell and Walker.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1404_1405
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• 2009

For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. $GeH_4$ is used in many applications with $Si_2H_6$ gas, such as amorphous alloy, a thin film of silicon and solar cell. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients, the electron drift velocity W, the longitudinal and transverse diffusion coefficient $ND_L$ and $ND_T$, and the ionization coefficient $\alpha$/N in $GeH_4$gas over the E/N range from 0.01 to 1000 Td by two-term approximation of the Boltzmann equation.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.455-462
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• 2016

The electron transport coefficients in not only pure atoms and molecules but also in the binary gas mixtures are necessary, especially on understanding quantitatively plasma phenomena and ionized gases. Electron transport coefficients (electron drift velocity, density-normalized longitudinal diffusion coefficient, and density-normalized effective ionization coefficient) in binary mixtures of TEOS gas with buffer gases such as Kr, Xe, He, and Ne gases, therefore, was analyzed and calculated by a two-term approximation of the Boltzmann equation in the E/N range (ratio of the electric field E to the neutral number density N) of 0.1 - 1000 Td (1 Td = 10⁻¹⁷ V.cm²). These binary gas mixtures can be considered to use as the silicon sources in many industrial applications depending on mixture ratio and particular application of gas, especially on plasma assisted thin-film deposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.159-162
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• 1998

This paper describes the electron transport characteristics in $SF_6$+He gas calculated for range of E/N values from 50~700[Td] by the Monte Carlo simulation and Boltzrnann equation method using a set of electmn collision cross sections determined by the authors and the values of electron swarm parameters are obtained by M F method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficents, longitudinal and h-ansverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.152-157
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• 1995

The electron transport coefficients in $SP_{6}$ gas is calculated and analysed for range of E/N values from 150∼800(Td) by a Monte Carlo simulation, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in neatly agreement with the respective experimental and theoretical for a range of E/N. The validity of the results obtained has been confirmed by a Monte Carlo simulation carried out parallel to the analysis.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.16-19
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• 1999

This paper describes the electron transport characteristics in $SF_6$+He gas calculated for range of E/N values from $50{\sim}700[Td]$ by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by TOF method. The results gained that the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.