• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.901-904
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• 2001

For the c-axis oriented epitaxial YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin film on r-cut sapphire substrate it is necessary to deposit buffer layers. The CeO$_2$buffer layer was deposited on sapphire substrate using RF magnetron sputtering system. We investigated XRD pattern of CeO$_2$thin films at various sputtering conditions such as sputtering gas ratio, sputtering power, target to substrate distance, sputtering pressure and substrate temperature. The optimum condition was 15 mTorr with deposition pressure, 1:1.2 with $O_2$and Ar ratio and 9cm with target to substrate distance. The CeO$_2$(200) peak was notable for a deposition temperature above 75$0^{\circ}C$. The YBa$_2$Cu$_3$O$_{7-{\delta}}$ was deposited on CeO$_2$buffered r-cut sapphire substrate using pulsed laser ablation. The YBa$_2$Cu$_3$O$_{7-{\delta}}$CeO$_2$(200)/A1$_2$O$_3$thin film was exhibited a critical temperature of 89K.xhibited a critical temperature of 89K.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.341-348
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• 1997

X-ray diffraction patterns of Pt/Co modulated films prepared by RF comagnetron sputtering method was investigated. Modulated films ([$Pt10.7\AA/Co2.8{\AA}{\times}{12}$]) were deposited on glass substrate with various sputtering conditions : sputtering with variations of gas pressures, sputtering with Xe instead Ar gas, and etching of the buffer layers. In order to obtain the structural information of Pt/Co modulated films, the structural model was constructed and calculated data of the model were compared with experimental ones. Comparison results showed that there were good agreements in satellite peak position and its intensity between them. This suggests that the realistic Pt/Co modulated film can be reproduced by our structure model.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.6
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• pp.398-404
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• 2000

The Ti-Al-V-N films have been deposited on various substrates by d.c and r.f reactive magnetron sputtering from a Ti-6Al-4V alloy target in mixed $Ar-N_2$ discharges. The films were investigated by means of XRD, AES, SEM/EDX, microhardness, TG and scratch test. The XRD and SEM results indicated that the films were of single B1 NaCl phase having dense columnar structure with the (111) preferred orientation. The composition of Ti-Al-V-N film was the Ti-7.1Al-4.3V-N(wt%) films. Adhesion and microhardness of Ti-Al-V-N films deposited by r.f magnetron sputtering method were better than those deposited by d.c magnetron sputtering method. The anti-oxidation properties of Ti-Al-V-N films were also superior to that of Ti-N film deposited by the same deposition conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.99-99
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• 2010

Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.510-515
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• 2014

Thin films of cubic $Na_{0.6}WO_3$, which is one of the sodium tungsten bronze, were fabricated by rf sputtering for the electrode applications in integrated sensors and actuators. A single-phase cubic $Na_{0.6}WO_3$ sputtering target of power type was prepared by conventional solid-state reaction. Thin films were deposited from the powder target, and the as-deposited films were amorphous, thus they annealed by tube furnace or RTP for crystallization. Thin films having cubic phase $Na_xWO_3$ were fabricated by the optimization of sputtering and post-annealing conditions, but single-phase cubic $Na_{0.6}WO_3$ thin films were not obtained. Although the films were not in single phase, they had good electrical conduction properties showing electrical resistivities of $10-4{\Omega}{\cdot}cm$ order.

• Korean Journal of Materials Research
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• v.21 no.12
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• pp.703-707
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• 2011

The electrochromic properties of tungsten oxide films grown by RF sputtering were investigated. Among the sputter parameters, first the $Ar:O_2$ ratios were controlled with division into only an $O_2$ environment, 1:1 and 4:1. The structure of each film prepared by these conditions was studied by X-ray diffraction, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. The sputter-deposited tungsten oxide films had an amorphous structure regardless of the $Ar:O_2$ ratios. The chemical compositions, however, were different from each other. The stoichiometric structure and low-density film was obtained at higher $O_2$ contents. Electrochemical tests were performed by cyclic voltammetry and chronoamperometry at 0.05 M $H_2SO_4$ solutions. The current density and charge ratio was estimated during the continuous potential and pulse potential cycling at -0.5 V and 1.8 V, respectively. The film grown in a higher oxygen environment had a higher current density and a reversible charge reaction during intercalation and deintercalation. The in-situ transmittance tests were performed by He-Ne laser (633 nm). At higher oxygen contents, a big transmittance difference was observed but the response speed was too slow. This was likely caused by higher film resistivity. Furthermore, the effect of sputtering pressure was also investigated. The structure and surface morphology of each film was observed by X-ray diffraction and scanning electron microscopy. A rough surface was observed at higher sputtering pressure, and this affected the higher transmittance difference and coloration efficiency.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1712-1715
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• 2018

To study the applications for ferroelectric non-volatile memory and ferroelectric memristor, etc., deposition pressure dependent electric the properties of $(Hf,\;Zr)O_2$ thin films by RF sputtering deposition method were investigated. The bottom electrode was TiN thin film to produce stress effect on the formation of orthorhombic phase and top electrode was Pt thin film by DC sputtering deposition. Deposition pressure was varied along with the same other deposition conditions, for example, sputtering power, target to substrate distance, post-annealing temperature, annealing gas, annealing time, etc. The structural and electric properties of the above thin films were investigated. As a result, it is confirmed that the electric properties of the $(Hf,\;Zr)O_2$ thin films depend on the deposition pressure which affects structural properties of the thin films, such as, structural phase, ratio of the constituents, etc.

• Transactions on Electrical and Electronic Materials
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• v.12 no.5
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• pp.209-212
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• 2011

Hafnium nitride (HfN) thin films were deposited onto a silicon substrate by inductive coupled nitrogen plasma-assisted radio frequency magnetron sputtering. The films were prepared without intentional substrate heating and a substrate negative bias voltage ($-V_b$) was varied from -50 to -150 V to accelerate the effects of nitrogen ions ($N^+$) on the substrate. X-ray diffractometer patterns showed that the structure of the films was strongly affected by the negative substrate bias voltage, and thin film crystallization in the HfN (100) plane was observed under deposition conditions of -100 $V_b$ (bias voltage). Atomic force microscopy results showed that surface roughness also varied significantly with substrate bias voltage. Films deposited under conditions of -150 $V_b$ (bias voltage) exhibited higher hardness than other films.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.77-82
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• 1995

PTCR(Positive Temperature Coefficient of Resistivity) thermistor in thin film BaTiO$_{3}$ system was prepared by using radio frequency(13.56 MHz) and DC magnetron sputter equipment. Polycrystalline, surface structure, and R-T(Resistivity-Temperature) characteristics of the specimens were measured by X-ray diffraction(D-Max3, Rigaku, Japan), SEM(Scanning Electron Microscopy: M.JSM84 01, Japan), and insulation resistance measuring system (Keithley 719), respectively. Thin films characteristics of the thermistor showed different properties depending on the substrate even with the same sputtering condition. The thin film formed on the A1$_{2}$O$_{3}$ substrate showed a good crystalline and a low resistivity at below curie point. However, the thin films prepared on slide glass and Si wafer were amorphous. The thicknesses of the three samples prepared under the same process conditions were 700[.angs.], 637.75[.angs.], and 715[.angs.], respectively.

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.733-739
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• 1998

C-axis oriented zinc oxide thin films were deposited on Cornign 1737 glass substrate by an rf magnetron sputtering technique. The effects of deposition parameters and post heat-treatment on the crystallinity and electical properties of ZnO films were investigaed. As-deposited ZnO films showed the strong c-axis growth and excellent crystallinity under the deposition conditions as follows: substrate temperature 350$^{\circ}C$ ; growth and excellent crystallinity under the deposition conditions as follows ; substrate temperature 350$^{\circ}C$ rf power 75W ; gas pressure 6m Torr; percentage of oxygen 50% The higher heat-treating temperatue was the stronger c-axis growth and the better crystallinity of the deposited ZnO films were. The resistivity of ZnO films was significantly affected by deposition parameters and post heat-treatment. With increasing increased. After post heat-treating at 400$^{\circ}C$ in air the resistivity of ZnO films increased but post heat-treat-ing temperature 500$^{\circ}C$ rather diminished the film resistivity.