• 한국초전도학회:학술대회논문집
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• v.9
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• pp.296-299
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• 1999

Bi$_2Sr_2CaCu_2O$(Bi-2212) thick films were fabricated on Y2l1 substrate by screen printing method. And the samples were annealed in various atmospheres, respectively. Though samples had many voids, the sample annealed in N$_2$ ; O$_2$ = 1:0 atmosphere and the sample in N$_2$ : O$_2$ = 0:1 showed some Bi 2212 low phase in comparison to other samples. The thickness of Bi-2212 on Y2ll substrates was about 20 ${\mu}$m.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.247-247
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• 2006

Chemical and physical synthesis routes were combined to prepare macroporous thin films of semiconducting metal-oxides such as $CaCu_{3}Ti_{4}O_{12}\;and\;TiO_{2}$ by sputtering onto (PMMA) microsphere templated substrates. Subsequently, the colloidal templates were removed by thermal decomposition. The remaining inorganic films comprised a monolayer of hollow hemispheres with diameter commensurate with that of the microspheres. This unique morphology increases the surface area and reduces the interfacial area between film and substrate. Consequently, the surface activity is markedly enhanced while deleterious interfacial effects between film and substrate are significantly reduced. Both effects are highly advantageous for gas sensing applications.

• Progress in Superconductivity and Cryogenics
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• v.7 no.1
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• pp.13-16
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• 2005

High temperature superconductor, $\YBa_2Cu_3O_{7-x}$ (YBCO) and ferroelectric, $\Ba_{0.1}Sr_{0.9}TiO_{3}$ (BST) multilayer thin films were deposited using on MgO(100) substrates pulsed laser deposition. The thin films exhibited only (001) peaks of YBCO and 1357 The HTS thin films demonstrated excellent zero resistance temperature of 92.5 K. We designed and fabricated HTS ferroelectric phase shifter using high frequency system simulator and standard photolithography method, respectively The HTS phase shifter shows a low insertion loss (2.97 dB) and large phase change ($\162^{circ}$) with 40 V do bias at 10 GHz. The HTS phase shifter shows 54 of figure of merit. These results can be applicable to phased anay antenna system for satellite communication services.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.250-250
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• 2010

We have prepared CIGS thin film absorber layers with simple solution spray deposition technique and thin film were synthesized with different atomic ratio. CIGS thin films were synthesized using non-vacuum solution deposition method on pre-heated sodalime glass substrates and Mo-coated soadlime glass substrate. In precursor solution were Cu : In : Ga: S ratio 4 : 3 : 2 : 8 and the crystal type of sprayed thin film were CIGS chalcopyrite structures. This structure was identified as typical chalcopyrite tetragonal structure with XRD analysis. This result showed that CIGS solution deposition technique has potential for the one step synthesis and low cost fabrication process for CIS or CIGS thin film absorber layer.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.288-290
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• 1997

Pulsed laser ablation has been used to fabricate superconducting $YBa_2Cu_3O_{7-x}$(YBCO) thin films on MgO substrates. The epitaxial YBCO thin films were grown at $750^{\circ}C$ and oxygen partial pressure of 200 mTorr. The electrical property and the characteristics of the YBCO thin films have been studied by R-T measurement. scanning electron microscopy (SEM) and X-ray diffraction (XRD). A microstrip line resonator has been fabricated using YBCO superconducting thin films by photolithography and wet-etch process. The resonator has linear microstrip line separated by a gap of 0.278 mm. We observed a fundamental resonance peak at the frequency of 10.007 GHz.

• Journal of Surface Science and Engineering
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• v.29 no.6
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• pp.803-808
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• 1996

Material and electrical characteristies of copper thin films prepared by metal organic chemical vapor deposition (MOCVD) have been investigated for interconnection applications in ultra large scale integration circuits (ULSI). The copper films have been deposited a TiN substrates using a metal organic precursor, hexafluoro acetylacetonate trimethyvinylsilane copper, VTMS(hfac)Cu (I). Deposition rate, grain size, surface morphology, and electrical resistvity of the copper films have been measuredfrom samples prepared at various experimental conditions, which include substrate temperature, chamber pressure, and carrier gas flow rate. Results of the experiment showed that the electrical property of the copper films is closely related to the crystallinity of the films. Lowest electrical resistivity, $2.4{\mu}{\Omega}.cm$ was obtained at the substrate temperature of $180^{\circ}C$, but the resistivity slightly increased with increasing substrate temperature due to the carbon content along the copper grain boundaries.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.3
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• pp.143-148
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• 2009

We have fabricated Ti metal films on Cu wire substrates by using a RF magnetron sputtering method at different RF powers (0, 30 and 60 W) in a high vacuum, and we have investigated the thin film characteristics and resistivity. The ion bombardment effect is increased by the method to superimpose RF power to DC power applied to two poles of the base; thus, the thin film is deposited at sputtering gas pressures below 1 Pa. Moreover, the thin film formation of the multilayer structure becomes possible by gradually injecting the RF power, and the thin film quality is improved.

• Progress in Superconductivity
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• v.9 no.2
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• pp.188-192
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• 2008

We investigated the size effect on quench development in $Au/YBa_2Cu_3O_7$ (YBCO) thin film meander lines on sapphire substrates. The meander lines were fabricated by patterning YBCO films coated with gold layers. The lines were subjected to simulated AC fault current, and immersed in liquid nitrogen during the experiment. After the initial rapid rise, the resistance increased moderately and then slowly. In 4 inch-diameter meander lines, the period during which the resistance increased moderately was considerably longer than in 2 inch-diameter line. Moderate increase of resistance was originated from quench propagation. The film temperature was about 180 K at the point when the propagation was completed. The rate of resistance increase after the quench completion was not affected by the film size.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.21-23
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• 2003

MOCVD method is one of promising techniques which can fabricate YBCO coated conductors in a low Price A continuous reel-to-reel MOCVD device using a dispersed solid source was designed and manufactured. YBCO films were deposited on various substrates of metallic silver, (100) MgO and SrTiO3 single crystals. The chemical composition of the metal organic sources was changed to optimize the processing condition associate to the deposition of the stoichiometric Y3a2Cu3O7-y. We report the superconducting transition temperature, surface morphology and chemical composition of the YBCO film surfaces.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.282-287
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• 2003

″H″ type resonator has the advantage for the miniaturization of high-T7 superconducting (HTS) microstrip antenna in comparison with the conventional microstrip antenna such as rectangular type or circular type. In this paper we designed miniaturized HTS antennas using this "H"-type resonator and reported the characteristics of our antennas including return loss, bandwidth, radiation patterns, efficiency and so on. To fabricate the "H" type antenna, HTS YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between 50 $\Omega$ feed line and HTS radiating patch. The ″H" type superconducting antenna showed the performance of 1.38 in SWR, 26 % in efficiency, and 13.8 dB in the return loss superior to the normal conducting counterpart.