• Transactions on Electrical and Electronic Materials
• /
• v.11 no.2
• /
• pp.81-84
• /
• 2010

Al-doped ZnO (AZO) films were prepared by an Ar:$H_2$ gas radio frequency (RF) magnetron sputtering system with a AZO ($2\;wt{\cdot}%\;Al_2O_3$) ceramic target at the low temperature of $100^{\circ}C$ and annealed in hydrogen ambient at the temperature of $300^{\circ}C$. To investigate the influence of the $H_2$ flow ratio on the properties of the AZO films, the $H_2$ flow ratio was changed from 0.5% to 2%. As a result, the AZO films, deposited with a 1% $H_2$ addition, showed a resistivity of $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. When the AZO films were annealed at $300^{\circ}C$ for 1 hour in a hydrogen atmosphere, the resistivity decreased from $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$ to $5.63\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. The lowest resistivity of $5.63\;{\times}\;10^{-4}{\Omega}{\cdot}cm$ was obtained by adding 1% hydrogen gas to the deposition and annealing process. The X-ray diffraction patterns of all the films showed a preferable growth orientation in the (002) plane. The spectrophotometer measurements showed that the transmittance of 85% was obtained by the film deposited with the $H_2$ flow ratio of 1% at 940 nm for GaAs/GaAlAs LEDs.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1540-1541
• /
• 2011

We calculated the electron transport coefficients in $H_2$+Ar gas calculated E/N values 0.01 ~ 1 Td by the Boltzmann equation method. This study gained the values of the electron swarm parameters such as the electron drift velocity and the transverse diffusion coefficients for $H_2$+Ar gas at a range of E/N. The transport coefficient W and Dt/u have been calculated in mixtures of 0.5% and 4% hydrogen in argon. All values were made at 293 K.

• Journal of Ceramic Processing Research
• /
• v.13 no.spc2
• /
• pp.260-264
• /
• 2012

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of IZO thin films intended for use as anode contacts in the organic light emitting diodes (OLED) devices. These IZO thin films were deposited on the PES film by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar + O2, and Ar + H2) at room temperature. In order to investigate the influences of the ambient gases, the flow rate of oxygen and hydrogen in argon has been changed from 0.1 sccm to 0.5 sccm, respectively. All the IZO thin film has an (222) preferential orientation regardless of ambient gases. The electrical resistivity of the IZO film increased with increasing O2 flow rate, whereas the electrical resistivity decreased sharply under an Ar + H2 atmosphere and was nearly similar regardless of the H2 flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. All the films showed the average transmittance over 85% in the visible range. The OLED device was fabricated with different IZO substrates made with the configuration of IZO/α-NPD/DPVB/Alq3/LiF/Al in order to elucidate the performance of the IZO substrate. The current density and the luminance of OLED devices with IZO thin films deposited in 0.5 sccm H2 ambient gas are the highest amongst all other films.

• Applied Chemistry for Engineering
• /
• v.25 no.2
• /
• pp.204-208
• /
• 2014

This study investigated the effect of hydrogen permeance and selectivity, catalyst amount, $H_2O/CO$ ratio in a feed stream, and Ar sweep gas on the performance of a water gas shift reaction in a membrane reactor. It was observed that a minimum hydrogen selectivity of 100 was needed in a membrane reactor to obtain a hydrogen yield higher than the one at equilibrium and the hydrogen yield enhancement gradually decreased as the hydrogen permeance increased. The CO conversion in a membrane reactor initially increased with the catalyst amount and reached a plateau later for a membrane reactor with a low hydrogen permeance while the high CO conversion independent of a catalyst amount was observed for a membrane reactor with a high hydrogen permeance. For the $H_2O/CO$ ratio in a feed stream higher than 1.5, a hydrogen permeance had little effect on the CO conversion in a membrane reactor and it was found that a minimum Ar molar flow rate of $6.7{\times}10^{-6}mol\;s^{-1}$ was needed to achieve the CO conversion higher than the one at equilibrium in a membrane reactor.

• Journal of the Korean Vacuum Society
• /
• v.9 no.3
• /
• pp.197-206
• /
• 2000

The deposition characteristics of MOCVD Cu using the (hfac)Cu(1,1-COD)(1,1,1,5,5,5-hexafluoro-2,4-pentadionato Cu(I) 1,5-cyclooctadine) have been investigated in terms of the effects of carrier gas such as hydrogen and argon as well as the effects of H(hfac) ligand addition. MOCVD Cu using a hydrogen carrier gas led to a higher deposition rate and lower resistivity than an argon carrier gas system. The improvement in the surface roughness of the MOCVD Cu films and the (111) preferred orientation texture was obtained by using a hydrogen carrier gas. However, the adhesion characteristics of the films showed relatively weaker compared to the Ar carrier gas system, probably due to the larger amount of F content in the films, which was confirmed by the AES analyses. When an additional H(hfac) ligand was added, the deposition rate was significantly enhanced in the case of an argon + H(hfac) carrier gas system while significant change in the deposition rate of MOCVD Cu was not observed in the case of the hydrogen carrier gas system. However, the addition of H(hfac) in both carrier gases led to lowering the resistivity of the MOCVD Cu films. In conclusion, this paper suggests the deposition mechanism of MOCVD Cu and is expected to contribute to the enhancement of smooth Cu films with a low resistivity by manipulating the deposition conditions such as the carrier gas and addition of H(hfac) ligand.

• Journal of the Korean Society for Heat Treatment
• /
• v.18 no.5
• /
• pp.281-287
• /
• 2005

Titanium aluminium nitride((TiAl)N) film is anticipated as an advanced coating film with wear resistance used for drills, bites etc. and with corrosion resistance at a high temperature. In this study, (TiAl)N thin films were deposited both at room temperature and at elevated substrate temperatures of 573 to 773 K by using a two-facing-targets type DC sputtering system in a mixture Ar and $N_2$ gases. Atomic compositions of the binary Ti-Al alloy target is Al-rich (25Ti-75Al (atm%)). Process parameters such as precursor volume %, substrate temperature and Ar/$N_2$ gas ratio were optimized. The crystallization processes and phase transformations of (TiAl)N thin films were investigated by X-ray diffraction, field-emission scanning electron microscopy. The microhardness of (TiAl)N thin films were measured by a dynamic hardness tester. The films obtained with Ar/$N_2$ gas ratio of 1:3 and at 673 K substrate temperature showed the highest microhardness of $H_v$ 810. The crystallized and phase transformations of (TiAl)N thin films were $Ti_2AlN+AlN{\rightarrow}TiN+AlN$ for Ar/$N_2$ gas ratio of 1:3, $Ti_2AlN+AlN{\rightarrow}TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 1:1 and $TiN+AlN{\rightarrow}Ti_2AlN+TiN+AlN{\rightarrow}Ti_2AlN+AlN{\rightarrow}Ti_2AlN+TiN+AlN$ for Ar/$N_2$ gas ratio of 3:1. The above results are discussed in terms of crystallized phases and microhardness.

• Journal of the Korean institute of surface engineering
• /
• v.48 no.6
• /
• pp.269-274
• /
• 2015

In this experiment, post-nitriding treatment was performed at $400^{\circ}C$ on AISI 316 stainless steel which was plasma carburized previously at $430^{\circ}C$ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% $N_2$, 50% $N_2$ and 75% $N_2$) for 4 hours. Additionally, during post nitriding Ar gas was used with $H_2$ and $N_2$ to observe the improvement of surface properties. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduced the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% $N_2$ gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment degraded the corrosion resistance of the sample compared with the carburized sample.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.177-178
• /
• 2012

In this experiment, post-nitriding treatment has been performed at $400^{\circ}C$ on AISI 316 stainless steel which is plasma carburized previously at $430^{\circ}C$ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% N2, 50% N2 and 75% N2) for 4 hours. Additionally, during post nitriding Ar gas was used with H2 and N2 to observe the improvement of treatment. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduces the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% N2 gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment were degraded the corrosion resistance of the sample compared with the carburized sample.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.2
• /
• pp.219-223
• /
• 2006

The thermal decomposition of tetrakis(ethylmethylamido) titanium (TEMAT) has been investigated in Ar and $H_2$ gas atmospheres at gas temperatures of 100-400 ${^{\circ}C}$ by using Fourier Transform infrared spectroscopy (FTIR) as a fundamental study for the chemical vapor deposition (CVD) of titanium nitride (TiN) thin film. The activation energy for the decomposition of TEMAT was estimated to be 10.92 kcal/mol and the reaction order was determined to be the first order. The decomposition behavior of TEMAT was affected by ambient gases. TEMAT was decomposed into the intermediate forms of imine (C=N) compounds in Ar and $H_2$ atmosphere, but additional nitrile (RC$\equiv$N) compound was observed only in $H_2$ atmosphere. The decomposition rate of TEMAT under $H_2$ atmosphere was slower than that in Ar atmosphere, which resulted in the extension of the regime of the surface reaction control in the CVD TiN process.

• Journal of the Korean Magnetics Society
• /
• v.11 no.4
• /
• pp.146-150
• /
• 2001

The effect of H$_2$ content in Ar sputtering gas on exchange coupling field(H$_{ex}$) for NiFe/FeMn interface was studied. When NiFe layer of Si(100)/Ta(50 $\AA$)/NiFe(60 $\AA$)/FeMn(250 $\AA$)Ta(50 $\AA$) was deposited at 8% H$_2$ in sputtering gas, the maximum exchange coupling field(H$_{ex}$) and minimum coercivity(H$_{c}$) were obtained. When Si(100)/Ta(50 $\AA$)/NiFe(60 $\AA$)/FeMn(250 $\AA$)/NiFe(70 $\AA$)/Ta(50 $\AA$) was deposited at 5% H$_2$ in sputtering gas, the maximum exchange coupling field(H$_{ex}$) of 148 Oe was obtained. The (111) preferred orientation and grain size of underlayer NiFe were increased and the internal stress was reduced by H$_2$ in sputtering gas. And the (111) preferred orientation and grain size of FeMn layer were also increased.d.ased.