• ETRI Journal
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• v.39 no.6
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• pp.866-873
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• 2017

We propose a multilayered-substrate-based power semiconductor discrete device package for a low switching loss and high heat dissipation. To verify the proposed package, cost-effective, low-temperature co-fired ceramic, multilayered substrates are used. A bare die is attached to an embedded cavity of the multilayered substrate. Because the height of the pad on the top plane of the die and the signal line on the substrate are the same, the length of the bond wires can be shortened. A large number of thermal vias with a high thermal conductivity are embedded in the multilayered substrate to increase the heat dissipation rate of the package. The packaged silicon carbide Schottky barrier diode satisfies the reliability testing of a high-temperature storage life and temperature humidity bias. At $175^{\circ}C$, the forward current is 7 A at a forward voltage of 1.13 V, and the reverse leakage current is below 100 lA up to a reverse voltage of 980 V. The measured maximum reverse current ($I_{RM}$), reverse recovery time ($T_{rr}$), and reverse recovery charge ($Q_{rr}$) are 2.4 A, 16.6 ns, and 19.92 nC, respectively, at a reverse voltage of 300 V and di/dt equal to $300A/{\mu}s$.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.105-110
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• 2014

The aim of this work was to investigate the effects of electrodeposition conditions on the microstructural characteristics of copper thin films. The microstructure of electroplated Cu films was found to be highly dependent on electrodeposition conditions such as system current and current density, as well as the bath solution itself. The current density significantly changed the preferred orientation of electroplated Cu films in a DC system, while the solution itself had very significant effects on microstructural characteristics in a pulse-reverse pulse current system. In the DC system, polarization at high current above 30 mA, changed the preferred orientation of Cu films from (220) to (111). However, Cu films showed (220) preferred orientation for all ranges of current density in the pulse-reverse pulse current system. The grain size decreased with increasing current density in the DC system while it remained relatively constant in the pulse-reverse pulse current system. The sheet resistance increased with increasing current density in the DC system due to the decreased grain size.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.9
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• pp.56-64
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• 1992

Because of a small bandgap energy, a high doping density, and a low operating temperature, the dark current in HgCdTe photodiode is almost composed of a tunneling current. The tunneling current is devided into an indirect tunneling current via traps and a band-to-band direct tunneling current. The indirect tunneling current dominates the dark current for a relatively high temperature and a low reverse bias and forward bias. For a low temperature and a high reverse bias the direct tunneling current dominates. In this paper, to verify the tunneling currents in HgCdTe photodiode, the new tunneling-recombination equation via trap is introduced and tunneling-recombination current is calculated. The new tunneling-recombination equation via trap have the same form as SRH (Shockley-Read-Hall) generation-recombination equation and the tunneling effect is included in recombination times in this equation. Chakrabory and Biswas's equation being introduced, band to band direct tunneling current are calculated. By using these equations, HgCdTe (mole fraction, 0.29 and 0.222) photodiodes are analyzed. Then the temperature dependence of the tunneling-recombination current via trap and band to band direct tunneling current are shown and it can be known what is dominant current according to the applied bias at athe special temperature.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.233-235
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• 2004

This paper studies protective coordination of utility interconnected multiple distirbuted generations(DG). The study of protective coordination interconnected DG has been conducted. A protective coordination of utility disturbed by reverse current of DG. Therefore, A protetive device is not operate when reverse current flows. In this paper, we use phase difference between V and I. Also, we studied protective coordination algorithm of utility interconnected multiple DG.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.136-137
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• 2009

전자파 차폐재로 메쉬를 제작하는 기존의 배치 방식은 복잡한 작업공정과 비싼 설비로 인해 생산원가 높다. 그래서 pulse reverse current를 이용하여 Cu mesh 도금을 하였다. 정펄스의 전류밀도가 $31mA/cm^2$일일 때 역펄스의 전류밀도 및 duty cycle에 상관없이 표면은 매끄럽게 나왔다. 정펄스의 전류밀도가 $454mA/cm^2$일때는 duty cycle이 25%이하는 표면상태가 매끄럽게 나타났지만 33%이상에서 표면상태가 거칠게 도금이 되었다.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1292-1294
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• 1996

The general output circuit for PWM output is pushpull using a complimentary MOSFET. The gate driver coupled directly at gate can switch easy upto a high frequency. However, a high reverse recovery current and parastic components make a oscillation output. This paper analyses this phenomenon and proposes a novel output circuit preventing the oscillation.

• Korean Journal of Materials Research
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• v.26 no.8
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• pp.412-416
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• 2016

The electrical properties of Au/n-type Ge Schottky contacts with different contact areas were investigated using current-voltage (I-V) measurements. Analyses of the reverse bias current characteristics showed that the Poole-Frenkel effect became strong with decreasing contact area. The contribution of the perimeter current density to the total current density was found to increase with increasing reverse bias voltage. Fitting of the forward bias I-V characteristics by considering various transport models revealed that the tunneling current is dominant in the low forward bias region. The contributions of both the thermionic emission (TE) and the generation-recombination (GR) currents to the total current were similar regardless of the contact area, indicating that these currents mainly flow through the bulk region. In contrast, the contribution of the tunneling current to the total current increased with decreasing contact area. The largest $E_{00}$ value (related to tunneling probability) for the smallest contact area was associated with higher tunneling effect.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2572-2574
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• 1999

본논문은 제작된 다이오드 switching시 나타난 전류 증가현상을 관측하고 그 원인을 분석했다. 증가현상을 보이는 구조는 다이오드에 전자를 조사한 소자로 proton을 조사한 구조에 비해서 접합부근에 high defect density 영역이 형성된다. Reverse recovery시에 이영역에 높은 역방향 전계가 형성, 조사에 순간적으로 전류가 증가하게 한다.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.9-16
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• 1991

The current status of reverse osmosis and ultrafiltration membranes are reviewed with the view for the future. In the case of reverse osmosis (RO) membranes, as examples, new crosslinked aromatic polyamide membranes exhibited the superior separation performance with the sufficient water permeability, the high tolerance for oxidizing agents and chemicals. Ultrafiltration (UF) membrane based on poly(phenylene sulfide sulfone) (PPSS) also exibited the superior separation performance with the high solvent, heat and fouling resistance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.87-91
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• 1998

In this paper, We analyzed the current-voltage characteristics with n-type silicon substrates concentration and temperature variations (Room temperature, 50$^{\circ}C$, 75$^{\circ}C$) in platinum silicide and silicon junction. The electrical parameters of measurement are turn-on voltage, saturation current, ideality factor, barrier height, dynamic resistance in forward bias and reverse breakdown voltage according to variations of junction concentration of substrates and measurement temperature variations. As a result, the forward turn-on voltage, reverse breakdown voltage, barrier height and dynamic resistance were decreased but saturation currents and ideality factor were increased by substrates increased concentration variations in platinum silicide and n-silicon junction. In increased measurement temperature (RT, 50$^{\circ}C$, 75$^{\circ}C$), the extracted electrical parameter values of characteristics were rises by increased temperature variations according to the forward and reverse bias.