• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.431-434
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• 2011

In this paper, bandwidth enhanced design of dielectric resonator antenna fabricated in multi-layer substrate is introduced. The proposed dielectric resonator antenna is operating with fundamental TE101 mode and higher-order TM111 mode. Each resonance frequency is dependent on resonator dimensions. As increasing the height of radiating aperture, the higher-order TM111 mode resonance frequency approach the fundamental TE101 mode resonance frequency and the antenna bandwidth increase by double resonance. Three different aperture height size antennas that operated at 7GHz are fabricated in FR4 multi-layer substrate. Measured 10 dB matching bandwidth is 8 percent for single resonace antenna and 18 percent for double resonance antenna.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.243-246
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• 2000

The sputtering systems mainly consist of the three-target holder. The target and substrate were the on-axis type. The MgO and STO substrate were used for the deposition of each layer. The optimum conditions of single-layer thin film were investigated from the SEM images and the XRD patterns. Based on the above conditions, the multi-layer thin films such as YBaCuO/LaGaO/Au/Nb and YBaCuO/Au/Nb were fabricated. The crystalline, the electrical Properties, the energy gap structure and the characteristics of the tunneling barrier on the multi-layer thin film have been investigated and characterized.

• Journal of IKEEE
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• v.25 no.1
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• pp.37-41
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• 2021

In this paper, a low-profile and broadband bowtie antenna using multi-layer substrate for UWB sensor application is presented. A compact bowtie antenna is designed and implemented on two multi-layered substrate with total thickness of 4.5 mm. The antenna consists of bowtie radiator and planar-type balun. The designed radiator and balun are connected to each other so that it can be easily implemented in various structures. The implemented antenna provides 3 to 6 dBi of gain for whole frequency range from 6.8 to 10 GHz.

• Journal of the Korea Society for Simulation
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• v.26 no.1
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• pp.69-75
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• 2017

An MCP(Multi-chip Package) is a package consisting of several chips. Since several chips are stacked on the same substrate, multiple assembly steps are required to make an MCP. The characteristics of the chips in the MCP are dependent on the layer sequence. In the MCP manufacturing process, it is very essential to carefully consider the layer sequence in scheduling to achieve the intended throughput as well as the WIP balance. In this paper, we propose a scheduling methodology considering the layer sequence constraint.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.37-37
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• 2002

Diamoncl/Mo/Ni multi-layers on SKH-51 steel substrate was prepared to improve the abrasive wear resistance of a tool and die by a commercial chemical vapor deposition unit and electro-plating. The diamond after 7 hour deposition had cuba-octahedral structure with 2~5$\mu\textrm{m}$ grains. The existence of non-ferrous metals such as chromium, nickel and molybdenum between diamond and SKH-51 substrate results in forming higher quality of diamond layer by retarding carbon diffusion in the diamond layer during deposition, and also improving hardness and wear resistance. Surface cracks on the film was sometimes observed by the difference of by the thermal expansion coefficients between the steel substrate and the deposited layers during cooling.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.814-818
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• 2016

DSSCs (dye-sensitized solar cells) based on $TiO_2/SiO_2$ multi layer AR (anti-reflection) coating on the outer glass FTO (fluorine-doped tin oxide) substrate are investigated. We have coated an AR layer on the surface of a DSSCs device by using an IAD (ion beam-assisted deposition) system and investigated the effects of the AR layer by measuring photovoltaic performance. Compared to the pure FTO substrate, the multi layer AR coating increased the total transmittance from 67.4 to 72.9% at 530 nm of wavelength. The main enhancement of solar conversion efficiency is attributed to the reduction of light reflection at the FTO substrate surface. This leads to the increase of Jsc and the efficiency improvement of DSSCs.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.618-618
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• 2013

Graphene is only one atom thick planar sheet of sp2-bonded carbon atoms arranged in a honeycomb crystal lattice, which has flexible and transparent characteristics with extremely high mobility. These noteworthy properties of graphene have given various applicable opportunities as electrode and/or channel for various flexible devices via suitable physical and chemical modifications. In this work, for the development of all-graphene devices, we performed to synthesize alternately patterned structure of mono- and multi-layer graphene by using the patterned Ni film on Cu foil, having much different carbon solid solubilities. Depending on the process temperature, Ni film thickness, introducing occasion of methane and gas ratio of CH4/H2, the thickness and width of the multi-layer graphene were considerably changed, while the formation of monolayer graphene on just Cu foil was not seriously influenced. Based on the alternately patterned structure of mono- and multi-layer graphene as a channel and electrode, respectively, the flexible TFT (thin film transistor) on SiO2/Si substrate was fabricated by simple transfer and O2 plasma etching process, and the I-V characteristics were measured. As comparing the change of resistance for bending radius and the stability for a various number of repeated bending, we could confirm that multi-layer graphene electrode is better than Au/Ti electrode for flexible applications.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.82-91
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• 1991

Molecular beam epitaxial growth of GaAs on Si substrate and the results on its analysis are reported. Epitaxy was performed on two different types of the substrate under various grwth conditions, and was analyzed by scanning and transmission electron microscopes, X-ray diffractometer, photoluminescence and Hall measurements. GaAs epitaxial layer has better crystalline quality when it was grown on a tilt-cut substrate. The stress seems to be releaxed more easily when multi-quantum well was introduced in the buffer layer. The epilayer was doped unintentionally with Si during growth due to the diffusion of the substrate. Also observed is that the quantum efficiency of excitonic radiative recombination of the heteroepitaxy is not as good as that of the homoepitaxy in the same doping level.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.1
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• pp.6-11
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• 2003

The multi layer spiral inductors, which enhance the quality factor Q of an inductor fabricated on the silicon substrate, has been designed using a TSMC CMOS 0.2sum 1-poly 5-metal layer technology. To investigate the performance of the designed inductors, a 2.5-dimensional field simulation tool(Momentum) is used. The simulation results show that the quality factor Q of the 5-metal inductor is improved 1.8 times over that of a convention31 spiral inductor at 2GHz for wireless LAN applications.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.1-5
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• 2004

A multi-layer flexible substrate is composed of copper(Cu)/polyimide that are known as good electrical conductivity, and low dielectric constant, respectively. In this study. conductor line of $5{\mu}m$-pitch was successfully fabricated without non-uniform pattern shape by electroplating copper and coating polyimide on patterned stainless steel. For multi-layer flexible substrate, via holes were drilled by UV laser and filled with electroplating copper and tin. And then, the PI layer with vias and conductor lines was stripped from stainless steel substrate. The PI layers were laminated at once with careful alignment between layers. Solid state reaction between tin and copper during lamination formed the intermetallic compounds of $Cu_6Sn_5$($\eta$-phase) and $Cu_3Sn$($\epsilon$-Phase) and achieved a complete inter-connection by vertically positioning the plugged via holes on via pad. The via formation process has several advantages; such as better electrical property and lower cost than V type via and paste via.