• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.809-816
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• 1995

Ti1-xAlxN films were successfully deposited on high speed steel and silicon wafer by plasma-assisted chemical vapor deposition using a TiCl4/AlCl3/N2/Ar/H2 gas mixture. Plasma process enabled N2 gas to nitride AlCl3, which is not possible in sense of thermodynamics. XPS analyses revealed that the deposited layer contained Al-N bond as well as Ti-N bond. Ti1-xAlxN films were polycrystalline and had single phase, B1-NaCl structure of TiN. Interplanar distance, d200, of (200) crystal plane of Ti1-xAlxN was, however, decreased with Al content, x. Al incorporation into TiN caused the grain size to be finer and changed strong (200) preferred orientation of TiN to random oriented microstructure. Those microstructural changes with Al addition resulted in the increase of micro-hardness of Ti1-xAlxN film up to 2800Kg/$\textrm{mm}^2$ compared with 1400Kg/$\textrm{mm}^2$ of TiN.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.69-76
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• 1993

The statistical methodology using RSM (response surface method) was used too ptimize the deposition conditions of selective CVD tungsten process for improving the deposition rate and the adhesion property. Temperature, flow rate of SiH$_4$ and WF$_6$ and H$_2$ and Ar carrier gases were chosen for the deposition variables and process characteristics due to carrier gas were intensively investigated. It was observed that temperature was the main factor influencingthe deposition rate in the case of H$_2$ carrier gas while the reactant ratio, $SiH_{4}/WF_{6}$, had the principal effect on the deposition rate in the case of Ar carrier gas. The increased deposition rate and the good adhesion to Si were obtained under Ar carrier gas compared to H$_2$ carrier gas. The optimum conditions for deposition rate and antipeeling property were found to be the temperature range of 300~32$0^{\circ}C$ and the reactant ratio, $SiH_{4}/WF_{6}$, of 0.5~0.6.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.121-121
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• 2011

Graphene formed by chemical vapor deposition was exposed to the various plasmas of Ar, O2, N2, and H2 to examine its effects on the bonding properties of graphene to metal. Upon the Ar plasma exposure of patterned graphene, the subsequently deposited metal electrodes remained intact, enabling successful fabrication of field effect transistor (FET) arrays. The effects of enhancing adhesion between graphene and metals were more evident from O2 plasmas than Ar, N2, and H2 plasmas, suggesting that chemical reaction of O radicals induces hydrophilic property of graphene more effectively than chemical reaction of H and N radicals and physical bombardment of Ar ions. From the electrical measurements (drain current vs. gate voltage) of field effect transistors before and after Ar plasma exposure, it was confirmed that the plasma treatment is very effective in controlling bonding properties of graphene to metals accurately without requiring buffer layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.321-322
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• 2009

Al doped ZnO films deposited on glass substrate using RF magnetron sputtering in Ar and $Ar+H_2$ gas ambient at $100^{\circ}C$. The films deposited in $Ar+H_2$ were hydrogen-annealed at the temperature of $150\sim300^{\circ}C$ for 1hr. The lowest resistivity of $4.25\times10^{-4}{\Omega}cm$ was obtained for the AZO film deposited in $Ar+H_2$ after hydrogen annealing at $300^{\circ}C$ for 1hr. The average transmittance is above 85% in the range of 400-1000 nm for all films. The absorption efficiency of solar cell was improved by using the optimized AZO films as a top electrode.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1336-1336
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• 1998

A twt -step carbothermal reduction scheme has been employed for the synthesis of SiC whiskers in an Ar or a H2 atmosphere via vapor-solid two-stage and vapor-liquid-solid growth mechanism respectively. It has been shown that the whisker growth proceed through the following reaction mechanism in an Ar at-mosphere : SiO2(S)+C(s)-SiO(v)+CO(v) SiO(v)3CO(v)=SiC(s)whisker+2CO2(v) 2C(s)+2CO2(v)=4CO(v) the third reaction appears to be the rate-controlling reaction since the overall reaction rates are dominated by the carbon which is participated in this reaction. The whisker growth proceeded through the following reaction mechaism in a H2 atmosphere : SiO2(s)+C(s)=SiO(v)+CO(v) 2C(s)+4H2(v)=2CH4(v) SiO(v)+2CH4(v)=SiC(s)whisker+CO(v)+4H2(v) The first reaction appears to be the rate-controlling reaction since the overall reaction rates are enhanced byincreasing the SiO vapor generation rate.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.426-428
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• 1989

As a first phase of plasma study intended for semiconductor processing research, we have studied the discharge phenomena. In particular, we have obtained a specific formula for the breakdown voltage as a function of the neutral state pressure of reactive gases. Our experimental results with H2,O2,Ar,CF4 seem ro verify this formula. In addition we find the voltage levels for various gases in the descending order of CF4>O2=Ar>H2 in high pressure region, while H2>CF4>O2>Ar in low pressure region. When H2 and CF4 were mixed, we observe the overall voltage dominated by the gas with lower breakdown volotage.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.155-159
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• 2007

This paper calculates and gives the analysis of electron swarm transport coefficients as described electric conductive characteristics of pure Ar, pure $SiH_4$, $Ar-SiH_4$ mixture gases ($SiH_4$--0.5%, 2.5%, 5%) over the range of E/N =$0.01{\sim}300$[Td], P=0.1, 1, 5.0[Torr] by Monte Carlo the Backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF, PT SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.106-109
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• 2002

This paper calculates and gives the analysis of electron swarm transport coefficients as described electric conductive characteristics of pure Ar, pure $SiH_4$, Ar + $SiH_4$ mixture gases ($SiH_4$--0.5%, 2.5%, 5%) over the range of E/N =0.01${\sim}$300[Td]. P=0.1, 1, 5.0[Torr] by Monte Carlo the Backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF. PT.SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation.

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.229-236
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• 1995

The effect of ${\alpha}_1$-adrenoceptor(${\alpha}_1$-AR) stimulation on intracellular pH($pH_i$), $Na^+$ activity($a_{Na}{^i}$) and contractility were investigated in isolated papillary muscles of euthyroid or hyperthyroid guinea pig with conventional microelectrode, $Na^+$ or $H^+$-selective microelectrodes, and tension transducer. Stimulation of the ${\alpha}_1$-AR by phenylephrine produced a decrease in $a_{Na}{^i}$ in euthyroid preparations. This decrease in $a_{Na}{^i}$ was abolished in presence of PKC activator, phorbol dibutyrate, and increased contrary to decrease. Phenylephrine also increased $a_{Na}{^i}$ in hyperthyroid ones. However, phenylrephtine produced an increase in $pH_i$ in both euthyroid and hyperthyroid ones. These changes were blocked by prazosin, an antagonist of ${\alpha}_1$-AR. These findings suggest that the changes in $a_{Na}{^i}$ and $pH_i$ are mediated by a stimulation of $Na^+-H^+$ exchange via ${\alpha}_1$-AR stimulation. This study focused on the increase in $a_{Na}{^i}$, $pH_i$ and contractility. The increase in $pH_i$ was blocked by amiloride or EIPA, $Na^+-H^+$ exchange inhibitors. Therefore, the increase in $a_{Na}{^i}$ and $pH_i$ mediated by ${\alpha}_1$-AR appeared to be due to an influx of $Na^+$ and a reduction of $H^+$ through $Na^+-H^+$ exchange. This study also revealed that the increase in $pH_i$ and $a_{Na}{^i}$ might be related to the sustained positive inotropic response. The $a_{Na}{^i}$ increase may contribute to the intracellular $Ca^{2+}$ through the $Na^+-Ca^{2+}$ exchange, and the $pH_i$ increase could cause an increase in the $Ca^{2+}$ sensitivity of myofilaments and may augment the ${\alpha}_1$-AR-mediated positive inotropic response.

• Resources Recycling
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• v.20 no.4
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• pp.71-77
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• 2011

$MoO_3$ powders were reduced to $MoO_2$ under Ar+$H_2$ gas mixture in a tubular furnace at temperature range 723~873 K. Reaction rate was quantitatively deduced by measuring relative humidity of off gas. Observed reaction rate increased significantly with hydrogen partial pressure and reaction temperature and the rate of $H_2O$ evolution increased drastically during the initial period of reduction. As reduction proceeded, however, $H_2O$ partial pressure decreased noticeably. During the initial period of the reduction, a linear relationship for time dependence of the reduction fraction was observed. The activation energy for the reduction of $MoO_3$ to $MoO_2$was 73.56 kJ/mol during the initial period of reduction.