• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.911-915
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• 2004

In this study, the electrical characteristics of high-voltage LDMOSFET fabricated by the existing CMOS technology were investigated depending on its process and design parameter. In order to verify the experimental data, two-dimensional device simulation was carried out simultaneously. The off- state breakdown voltages of n-channel LDMOSFETs were increased nearly in proportional to the drift region length. For the case of decreasing n-well ion implant doses from $1.0\times{10}^{13}/cm^2$ to $1.0\times{10}^{12}/cm^2$, the off-state breakdown voltage was increased approximately two times. The on-resistance was also increased about 76 %. From 2-D simulation, the increase in the breakdown voltage was attributed to a reduction in the maximum electric field of LDMOS imolanted with low dose as well as to a shift toward n+ drain region. Moreover, the on- and off-state breakdown voltages were also linearly increased with increasing the channel to n-tub spacing due to the reduction of impact ionization at the drift region. The experimental and design data of these high-voltage LDMOS devices can widely applied to design smart power ICs with low-voltage CMOS control and high-voltage driving circuits on the same chip.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권1호
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• pp.18-22
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• 2005

We have proposed and fabricated a dual gate AlGaN/GaN high electron mobility transistor (HEMT), which exhibits the low leakage current and the high breakdown voltage for the high voltage switching applications. The additional gate between the main gate and the drain is specially designed in order to decrease the electric field concentration at the drain-side of the main gate. The leakage current of the proposed HEMT is decreased considerably and the breakdown voltage increases without sacrificing any other electric characteristics such as the transconductance and the drain current. The experimental results show that the breakdown voltage and the leakage current of proposed HEMT are 362 V and 75 nA while those of the conventional HEMT are 196 V and 428 nA, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권4호
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• pp.246-248
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• 2000

Closed-form expressions for the temperature dependent breakdown voltage and the on-resistance of the Si power MOSFETs were derived by employing effective temperature dependent ionization coefficient for electrons and holes. The breakdown voltage increases by 20% and the on-resistance increases 2 times when the temperature increases from 300 K to 423 K. The analytic results normalized to the values at 300 K show good agreement with the experimental data of Motorola within 3.5% and 7% for the breakdown voltage and the on-resistance, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권9호
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• pp.605-610
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• 1999

An SOI(Silicon-On-Insulator) LD(Lateral Double-diffused)MOS with a recessed source structure is proposed to improve the on-resistance and the breakdown voltage. The recessed source structure can decrease the on-resistance by reducing the path of electron current, also increase the breakdown voltage by extending the effective length of gate field plate. Simulation results by TSUPREM4 and MEDICI have shown that the on-resistance of the LDMOS with a recessed source was 26% lower than conventional LDMOS. The breakdown voltage of proposed device was found to be 45V while that of conventional device was 36.5 V. At the same breakdown voltage of 36.5V, the on-resistance of the LDMOS with a recessed source was 41% lower than that of conventional structure.

• 전기학회논문지
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• 제61권12호
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• pp.1872-1876
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• 2012

A calculation method of the breakdown voltage for the drain region with the cylindrical structure in LDMOS is proposed. The depletion region of the drain is divided into many smaller regions and the doping concentration of each split region is assumed to be uniformly distributed. The field and potential in each split region is calculated by the integration of the Poisson equation and the ionization integral method is used to compute the breakdown voltage. The breakdown voltage resulted from the proposed method shows the maximum relative error of 2.2% compared with the result of the 2-dimensional device simulation using BANDIS.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.149-150
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• 2005

Thyristor breakdown voltage variation acceleration aging test was investigated. The breakdown voltage was deceased after 1000 hours acceleration aging test. It temperature rising caused by electric field concentration at the edge beveling region of the thyristor was confirmed using Silvaco device simulation. The local temperature rising is driving force for the defect propagation. Consequently, propagated defects of the beveling region seems to decrease thyristor's breakdown voltage.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.631-635
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• 2007

Diagnostic, surge and ac breakdown tests are widely used to evaluate the insulation condition of stator winding in traction motor. Diagnostic test included ac current, tan delta and maximum partial discharge. The result of diagnostic test indicates that five kinds of stator windings are good condition. Surge test was peformed to confirm the healthy of turn insulation in stator windings. This test is very easy to detect the turn insulation failure between normal and defect stator windings. After completing the diagnostic test, ac breakdown test has conducted gradually increasing ac voltage, until the stator winding punctured. No. 5 stator windings failed near rated voltage of 18.9 kV The breakdown voltage of No. 1 stator windings was 13.0 kV The ac breakdown voltage of normal winding is about 1.45 times higher than that of defect windings. The failure was located in a line-end coil at the exit from the core slot.

• 한국초전도ㆍ저온공학회논문지
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• 제17권3호
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• pp.37-40
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• 2015

Recently, the electrical insulation design for electrical apparatuses is important to cope with the tendency of high voltage. The degradation characteristics of a superconducting coil due to an electrical breakdown should be considered to design a high voltage superconducting coil. In this paper, the degradation characteristics of 2G high temperature superconducting (HTS) wires are studied with respect to electrical breakdown tests. To analyze the dependency of the degradation characteristics of 2G HTS wires, the electrical breakdown tests are performed with AC(alternating current) and DC(direct current) voltage. All tests are performed by applying various magnitudes of AC and DC breakdown voltages. To verify the degradation characteristics of 2G HTS wires, the tests are performed with various 2G HTS wires with respect to stabilizer materials. The degradation characteristics of 2G HTS wires, such as Ic(critical current) and index number are measured by performing electrical breakdown tests. It is found that the characteristics such as Ic and index number can be degraded by an electrical breakdown. Moreover, it is concluded that the degradation characteristics of 2G HTS wires are affected by the stabilizer material and applied voltages. The cross-sectional view of 2G HTS wires is observed by using a scanning electron microscope (SEM). As results, it is found that the degradation characteristics of 2G HTS wires are concerned with hardness and electrical conductivity of stabilizer layers.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.646-652
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• 2010

This paper investigates a method to improve the breakdown voltage characteristics of a gas discharge arrester (GDA) for a surge suppressor. The middle electrode is inserted between two terminal electrodes. Voltage application to the electrode synchronized and amplified by the impulse voltage decreases spark overvoltage from 45% to 57.6%. The decrease is caused by higher voltage slope, as opposed to applied impulse voltage (by 5.5 to 6.2 times). In addition, the GDA model using ATP-Draw was used to analyze the operation characteristics of GDAs. The test and simulation results agree to within 2% when the trigger source was used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.302-305
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• 1989

Ac, dc and impulse dielectric strengths of $LN_2$ at 0.1MPa were investigated experimentally, referring to the behavior of thermally induced bubble, which might be generated at quenching condition of immerged-cooling superconducting devices. The experimental results show that the bubble shape under electric field stress depends significantly on the applied voltage waveform. With ac voltage, the breakdown voltage of $LN_2$ falls suddenly near to one of the saturated gas at the threshold heater power of boiling onset. In control to this, the reduction of impulse breakdown voltage with heater peter is gradual and the time to breakdown depends on the existence of thermal bubble. These breakdown characteristics can be explained satisfactorily by the bubble behavior under electric fields.