• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.43-43
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• 2003

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.6
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• pp.350-355
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• 2014

Bottom-gate tin oxide ($SnO_2$) thin film transistors (TFTs) were fabricated on $N^+$ Si wafers used as gate electrodes. 60-nm-thick $SnO_2$ thin films acting as active layers were sputtered on $SiO_2/Al_2O_3$ films. The $SiO_2/Al_2O_3$ films deposited on the Si wafers were employed for gate dielectrics. In order to increase the resistivity of the $SnO_2$ thin films, oxygen mixed with argon was introduced into the chamber during the sputtering. The mobility of $SnO_2$ TFTs was measured as a function of the flow ratio of oxygen to argon ($O_2/Ar$). The mobility variation with $O_2/Ar$ was analyzed through studies on crystallinity, oxygen binding state, optical properties. X-ray diffraction (XRD) and XPS (X-ray photoelectron spectroscopy) were carried out to observe the crystallinity and oxygen binding state of $SnO_2$ films. The mobility decreased with increasing $O_2/Ar$. It was found that the decrease of the mobility is mainly due to the decrease in the polarizability of $SnO_2$ films.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.8
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• pp.8-14
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• 1997

RuO$_{2}$ thin films are prepared by RF magnetron reactive sputtering and their characteristics of crystallization, microstructue, surface roughness and resistivity are studied with various O$_{2}$/(Ar+O$_{2}$) ratios and substrate temperatures. As O$_{2}$/(Ar+O$_{2}$) ratio decreas and substrate temperature increases, the preferred growing plane of RuO$_{2}$ thin films are changed from (110) to (101) plane. With increase of the O$_{2}$/(Ar+O$_{2}$) ratio from 20% to 50%, the surface roughness and the resistivity of RuO$_{2}$ thin films increase form 2.38nm to 7.81 nm, and from 103.6.mu..ohm.-cm to 227.mu..ohm.-cm, resepctively, but the deposition rate decreases from 47 nm/min to 17nm/min. On the other hand, as the substrate temperature increases form room temperature to 500.deg. C, resistivity decreases from 210.5.mu..ohm.-cm to 93.7.mu..ohm.-cm. RuO$_{2}$ thin film deposited at 300.deg. C shows a execellent surface roughness of 2.38nm. As the annealing temperature increases in the range between 400.deg. C and 650.deg. C, the resistivity decreases because of th improvement of crystallinity. We find that RuO$_{2}$ thin film deposited at 20% of O$_{2}$/(Ar+O$_{2}$) ratio and 300.deg. C of substrate temperature shows execellent combination of surface smoothness and low resistrivity so that it is well qualified for bottom electrodes for ferroelectric thin films.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.494-498
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• 2000

RuO$_2$ thin films are prepared by RF magnetron reactive sputtering and their characteristics of crystallization, microstructure, surface roughness and resistivity are studied with various $O_2$/ (Ar+O$_2$) ratios and substrate temperatures. As $O_2$/(Ar+O$_2$) ratio decreases and substrate temperature increases, the preferred growing plane of RuO$_2$ thin films are changed from (110) to (101) plane. With increase of the $O_2$/(Ar+O$_2$) ratio from 20% to 50%, the surface roughness and the resistivity of RuO$_2$ thin films increase from 2.38nm to 7.81 nm, and from 103.6 $\mu$$\Omega$-cm to 227 $\mu$$\Omega$-cm, respectively, but the deposition rate decreases from 47 nm/min to 17 nm/min. On the other hand, as the substrate temperature increases from room temperature to 500 $^{\circ}C$, resistivity decreases from 210.5 $\mu$$\Omega$-cm to 93.7 $\mu$$\Omega$-cm. RuO$_2$ thin film deposited at 300 $^{\circ}C$ shows a excellent surface roughness of 2.38 nm. As the annealing temperature increases in the range between 400 $^{\circ}C$ and 650 $^{\circ}C$, the resistivity decreases because of the improvement of crystallinity. We find that RuO$_2$ thin film deposited at 20% of $O_2$/(Ar+O$_2$) ratio and 300 t of substrate temperature shows excellent combination of surface smoothness and low resistivity so that it is well Qualified for bottom electrodes for ferroelectric thin films.

• Journal of the Korean Vacuum Society
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• v.13 no.4
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• pp.139-144
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• 2004

Recently, the importance of clean vacuum and partial pressure measurement of gas species has been increased in the vaccum process. In this study, the partial pressures of $H_2$, He, C, N, $O_2$, $H_2O $, Ar/2, $N_2$(CO), Ar, $CO_2$ were measured by residual gas analyzer according to temperature of cryogenic pump which is used to clean vacuum generation and compared. The experimental results showed that the cryopanel temperature was reached to 12K after 72 minutes of pumping and after 25hours, the partial pressures in percent were 24.9 %, 6.6%, 5.5 %, 2.2 %, 3.8%, 30.7%, 6.5%, 6.1 %, 5.5%, 8.2% for $H_2$, He, C, N, $O_2$, $H_2O $, Ar/2, $N_2$, Ar, $CO_2$ respectively. The dominant gases were $H_2$ and $H_2O $, and the partial pressures were relatively high compare to other gases.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.25.1-28
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• 2000

In this study, $Y_2O_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$were investigated by varying $Cl_2$/($Cl_2$+Ar) gas mixing ratio. The maximum etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$ were 302/min, and 2.4 at $Cl_2$/($Cl_2$+Ar) gas mixing ratio of 0.2 repetitively. In x-ray photoelectron spectroscopy (XPS) analysis, $Y_2O_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCl, and $YC_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.25-28
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• 2000

In this study, $Y_2$O$_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of $Y_2$O$_3$, and the selectivity of $Y_2$O$_3$ to YMnO$_3$ were investigated by varying Cl$_2$/(Cl$_2$+Ar) gas mixing ratio. The maximum etch rate of $Y_2$O$_3$, and the selectivity Of $Y_2$O$_3$ to YMnO$_3$ were 302/min, and 2.4 at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2 repectively. In x-ray photoelectron spectroscopy (XPS) analysis, $Y_2$O$_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCI, and YCl$_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.62-65
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• 2001

$SrBi_2Ta_2O_{9}$ thin films were etched in inductively coupled $Cl_{2}$/$CF_{4}$/Ar plasma. The maximum etch rate was 1060 $\AA\textrm{m}$/min in $Cl_{2}$/$CF_{4}$/Ar (80). The chemical reactions on the etched surface were studied with x-ray photoelectron spectroscopy. The etching of SBT thin films in $Cl_{2}$/$CF_{4}$/Ar were etched by chemically assisted reactive ion etching. The small addition of $Cl_2$ into $CF_4$(20)/Ar(80) plasma will decrease the fluorine radicals and the increase Cl radical.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.294-300
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• 2017

$TeO_x$ thin films were deposited at various $O_2$/Ar gas-flow ratios by a reactive RFmagneton sputtering technique from $TeO_2$ and Te targets. X-ray diffraction (XRD) results revealed that the $TeO_x$ thin films were amorphous. The structure and chemical composition of the $TeO_x$ thin films were investigated by fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The optical characteristics of the $TeO_x$ thin films were investigated by an Ellipsometer and a UV-VIS-NIR spectrophotometer. According to the $O_2$/Ar gas-flow ratios, the atomic composition ratio of $TeO_x$ thin films was divided into two regions(x=1-2, 2-3). Different optical characteristics were shown in each region. With an increasing $O_2$/Ar gas-flow ratio, the refractive index of the $TeO_x$ thin films decreased and the optical bandgap of the films increased.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.92-94
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• 2003

The sputtering yield change of an amorphous Si layer on Si(100) was measured quantitatively for 0.5 keV $O_2^{+}$ and $Ar^{+}$ ion bombardment with in suit MEIS. In the case of 0.5 keV $O_2^{+}$ ion bombardment, at the initial stage of sputtering before surface oxidation, the sputtering yield of Si was 1.4 (Si atoms/$O_2^{+}$) and then decreased down to 0.06 at the ion dose of $3\times10^{16}O_2\;^{+}\textrm{/cm}^2$. In the case of 0.5 keV $Ar^{+}$ ion bombardment, the sputtering yield of Si for the surface normal incidence was 0.56 at the ion dose of 2.5 ${\times}$ 10$^{15}$ $Ar^{+}\textrm{cm}^2$, and rapidly saturated to 1.2 at dose of $7.5\times10^{15}Ar^+\textrm{cm}^2$. For the incidence angle of 80 from surface normal, the sputtering yield of Si was saturated to about 1.4 at the initial stage of sputtering. The surface transient effects, caused by change in sputtering yield at the initial stage of sputtering can be negligible when 0.5 keV $Ar^{+}$ ion at extremely grazing angle was used for sputter depth profiling.g.