• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.515-518
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• 2000

The electrochromic properties of $WO_{3}$/$MoO_{3}$ and $MoO_{3}$/$WO_{3}$ double-layers have been systemically studied. The double-layers were made by a e-beam evaporation method and investigated by studying optical modulation, transmittance, and cyclic voltammetry. The devices exhibit good optical properties with wavelength range of 400 to 1100 nm(visible and infrared) during coloration as a function of lithium ion charge injection. It has shown that the double-layer electrochromic thin films are improved the electrochromic properties, but the electrochemical properties are less stable.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.861-864
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• 2000

Ferroelectric thin film capacitors with high dielectric constant are important for the application of memory devices. In this work, thin films of PLT(28)(Pb$\sub$0.72/La$\sub$0.28/Ti$\sub$0.93/O$_3$) were fabricated on Pt/Ti/SiO$_2$/Si substrates in-situ annealing and ex-situ annealing have been compared depending on the annealing time. We have systematically investigated the variation of grain sizes depending on the condition of post-annealing and the variation of deposition rate. C-V measurement, ferroelectric properties, leakage current and SEM were performed to investigate the electrical properties and the microstructural properties of Pb(La,Ti)O$_3$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.376-382
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• 2000

We successfully fabricated OLED(Organic Light Emitting Diodes) with Al cathodes electrode deposited by the DC magnetron sputtering. The effects of a controlled Al cathode layer of an Indium Tin Oxide (ITO)/blended single polymer layer (PVK Bu:PBD:dye)/Al light emitting diodes are described. The PVK (Poly(N-vinylcarbazole)) and Bu-PBD (2-(4-biphenyl-phenyl)-1,3,4-oxadiazole) are used hole transport polymer and electron transport molecule respectively. We found that both current injection and electroluminescence output are significantly different with a variable DC sputtering power. The difference is believed to be due to the influence near the blended polymer layer/cathode interface that results from the DC power and H$\sub$2//O in a chamber. And DC sputtering deposition is an effective way to fabricate Al electrodes with pronounced orientational characteristics without damage occurring to metal-organic interface during the sputtering deposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.486-489
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• 2003

Red organic electroluminescent(EL) devices based on poly(N-vinylcarbazole)(PVK) and tris(8-hydroxyquinorine aluminum)($Alq_3$) doped with red emissive material, 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran(DCJTB), poly(3-hexylthiophene)(P3HT), Rubrene and 4-dicyanomethylene-2-methyl-6[2-(2,3,6,7-tetrahydro-1H,5H-benzo-[i.j])quinolizin-8yl)vinyl-4H-pyran(DCM2) were fabricated. We examine the energy transfer from $Alq_3$ to DCJTB, P3HT, Rubrene and DCM2 by comparing between the PL and EL spectrum. The maximum peak PL intensities were achieved when the doping concentration of DCJTB, DCM2, P3HT and Rubrene has 5, 1, 0.5, 2wt%, respectively. The maximum luminance of device using DCJTB showed $594\;cd/m^2$ at 15V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.494-497
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• 2003

We report the dark spots in organic light emitting diodes by using a near-field scanning microwave microscope. Devices structure was glass / indium-tin-oxide(ITO) / copper-pthalocyiane(Cu-Pc) / tris-(8-hydroquinoline)aluminum(Alq3) / aluminum(Al). We made artificial dark spots by using a etching technique on a ITO substrate. Near-field scanning microwave microscope images and reflective coefficient of dark spots were measured and compared by the change of various applied voltage changes 0-15V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.276-279
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• 2004

CdS thin films on polymer substrates such as polycarbonate(PC) and polyethylene terephthalat(PET) have many merits such as light weight, small volume and can make the obtained devices folded, easily carried. In present work, CdS thin films on glass, PC, and PET substrates have been prepared by chemical bath deposition. The structural and optical propertied of the films depending on substrate types have been investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.163-166
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• 2003

The electrothermal simulation of high voltage LIGBT(Lateral Insulated Gate Bipolar Transistor) in thin Silicon on insulator (SOI) and Silicon on sapphire (SOS) for thermal conductivity and sink is performed by means of MEDICI. The finite element simulations demonstrate that the thermal conductivity of the buried oxide is an important parameter for the modeling of the thermal behavior of silicon-on-insulator (SOI) devices. In this paper, using for SOI LIGBT, we simulated electrothermal for device that insulator layer with $SiO_2\;and\;Al_2O_3$ at before and after latch up to measured the thermal conductivity and temperature distribution of whole device and verified that SOI LIGBT with $Al_2O_3$ insulator had good thermal conductivity and reliability

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.372-375
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• 2003

MCA deflection control is a important technology for the development of MEMS applications. In this study, deflection analysis at the MLA/Si diaphragm was investigated by Finite Element Method. Analysis of Si diaphragm combined with MCA has been implemented into the ANSYS (Solid5 and Solid45). On the basis of this structure, deflection versus MCA number of layers has been modelled and MCA/Si contact area characteristics with different diaphragm conditions were analyzed. Consequently, it is expected that fabrication technology of MCA/Si diaphragm could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.108-111
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• 2003

Currently, molecular devices are reported utilizing active self-assembled monolayers containing the nitro group as the active component, which has active redox centers[1]. We confirm the electrical properties of 4,4-di(ethynylphenyl)-2'-nitro-1-benzenethiolate. To deposit the SAM layer onto gold electrode, we transfer the prefabricated Au(111) substrates into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured current-voltage curve using ultra high vacuum scanning tunneling microscopy (UHV STM), I-V curve also clearly shows several current peaks between the negative bias region (-0.3958V) and the positive bias region (0.4658V), respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.353-356
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• 2004

This paper discribes the analysis of the I-V characteristics of 4H-SiC DiMOSFET with single epi-layer Silicon Carbide has been around for over a century. However, only in the past two to three decades has its semiconducting properties been sufficently studied and applied, especially for high-power and high frequency devices. We present a numerical simulation-based optimization of DiMOSFET using the general-purpose device simulator MINIMIS-NT. For simulation, a loin thick drift layer with doping concentration of $5{\times}10^{15}/cm^3$ was chosen for 1000V blocking voltage design. The simulation results were used to calculate Baliga's figure of Merit (BFOM) as the criterion structure optimization and comparison.