• 한국세라믹학회지
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• 제34권12호
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• pp.1227-1234
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• 1997

ZnO thin films were prepared by rf-magnetron sputter at various conditions. Crystallinity, microstructure, chemical composition, and optical composition, and optical properties of the films were investigated as functions of substrate temperature (R. T.-50$0^{\circ}C$) an sputter gas (O2/Ar=0-50%). ZnO thin films grown at 50$0^{\circ}C$ with sputter gas of pure argon as well as at R. T. with sputter gas of a mixture of argon & oxygen(O2/Ar=2%) exhibit a strong tendency of (002) preferred orientation, compared with a considerable random orientation at the other conditions. The thin films with (002) preferred orientation has a chemical stoichiometry of Zn/O-1.01, a band gap of 3.3eV, and a packing density of 98% respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.770-772
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• 1998

The highest etch rate of Pt film was obtained at 10% $Cl_2$/90% Ar gas mixing ratio in our previous investigation. However, the problems such as the etch residues(fence) remained on the pattern sidewall, low selectivity to oxide as mask and low etch slope were presented. In this paper, the etching by additive $O_2$ gas to 10% $Cl_2$/90% Ar gas base was examined. As a result, the fence-free pattern and high etch slope was observed and the selectivity to oxide increased without decreasing of the etch rate. And the reasons for this phenomenon was investigated by XPS(x-ray photoelectron spectroscopy) surface analysis and plasma characteristic.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.300-315
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• 2005

Recently plasma surface-cleaning or surface-etching techniques have been focused in the respect of decontamination of spent or used nuclear parts and equipment. In this study decontamination rate of metallic cobalt surface was experimentally investigated via its surface etching rate with a $CF_4-O_2$ mixed gas plasma and metallic surface wastes of cobalt oxides were simulated and decontaminated with $NF_3$ - Ar mixed gas plasma. Experimental results revealed that a mixed etchant gas with about $80{\%}\;CF_4-20{\%}\;O_2$ gives the highest reaction rate of cobalt disk and the rate reaches with a negative 300 DC bias voltage up to $0.43\;{\mu}m$/min at $380^{\circ}C$ and $20{\%}\;NF_3-80\%$ Ar mixed gas gives $0.2\;{\mu}m$/min of reaction rate of cobalt oxide film.

• 한국안전학회지
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• 제23권5호
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• pp.79-83
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• 2008

The corrugated stainless steel tubing(CSST) for the fuel gas piping system can be installed easily and quickly. It is often constructed under the ceiling and the wall which has a good flexibility and installation in comparison with iron pipe. However, the quality of the CSST is determined to depend upon the welding skill of stainless steel tubing. In this study, it is tested by controlling jet point of Ar as inert and cooling gas, and also compared with the bead state of welding point and the performance. As a result, it has the best condition when the jet point of Ar is located behind $5{\sim}10mm$ of the welding point.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.72-75
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• 2005

In this study Al electrode for OLED was deposited by FTS(Facing Targets Sputtering) system which can deposit thin films with low substrate damage. The Al thin films were deposited on the cell(LiF/EML/HTL/Bottom electrode) as a function of working gas such as Ar, Kr or mixed gas. Also Al thin films were prepared with working gas pressure (1, 6 mTorr ). The film thickness and I-V curve of Al/cell were evaluated by $\alpha$-step and semiconductor parameter (HP4156A) measurement. In the results, when Al thin film were deposited using pure Ar gas, the turn-on voltage of Al/cell was about 11[V]. And the turn-on voltage of Al/cell can be decrease to about 7[V].

• 공업화학
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• 제25권2호
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• pp.204-208
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• 2014

본 연구는 1차원 반응기 모델을 이용한 수치 시뮬레이션을 통해 수소투과량, 수소선택도, 사용된 촉매의 양, 급송흐름에서의 $H_2O/CO$ 조성비 및 Ar sweep gas가 막반응기(membrane reactor)에서의 수성가스전이반응의 성능에 미치는 영향을 분석하였다. 막반응기에서 평형상태보다 향상된 수소수율을 얻기 위해선 적어도 100 이상의 수소선택도를 가져야 함이 관찰되었으며, 수소투과량이 계속 증가될 경우에는 수소수율의 증가폭이 점차 감소됨이 보였다. 낮은 수소투과량의 경우에는 촉매량이 증가할수록 초기엔 증가된 CO 전환율을 보이다가 점차 그 증가폭이 감소되었으며, 높은 수소투과량의 경우에는 촉매의 양과 무관하게 높은 CO 전환율이 관찰되었다. 급송흐름에서의 $H_2O/CO$ 조성비가 1.5 이상인 경우엔 수소투과량이 막반응기에서의 CO 전환율에 미치는 영향이 미미하였고, 막반응기에서 평형상태보다 향상된 CO 전환율을 얻기 위해선 적어도 $6.7{\times}10^{-6}mol\;s^{-1}$ 의 Ar 몰유속이 필요함이 밝혀졌다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.77-77
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• 2011

These days, a growing demand for memory device is filled up with the flash memory and the dynamic random access memory (DRAM). Although DRAM is a reasonable solution for current demand, the universal novel memory with high density, high speed and nonvolatility, needs to be developed. Among various new memories, the magnetic random access memory (MRAM) device is considered as one of good candidate memories because of excellent features including high density, high speed, low operating power and nonvolatility. The etching of MTJ stack which is composed of magnetic materials and insulator such as MgO is one of the vital process for MRAM. Recently, MgO has attracted great interest in the MTJ stack as tunneling barrier layer for its high tunneling magnetoresistance values. For the successful realization of high density MRAM, the etching process of MgO thin films should be investigated. Until now, there were some works devoted to the investigations on etch characteristics of MgO thin films. Initially, ion milling was applied to the etching of MgO thin films. However, ion milling has many disadvantages such as sidewall redeposition and etching damage. High density plasma etching containing the magnetically enhanced reactive ion etching and high density reactive ion etching have been employed for the improvement of etching process. In this work, inductively coupled plasma reactive ion etching (ICPRIE) system was adopted for the improvement of etching process using MgO thin films and etching gas mixes of $CH_4$/Ar and $CH_4$/$O_2$/Ar have been employed. The etch rates are measured by a surface profilometer and etch profiles are observed using field emission scanning emission microscopy (FESEM). The effects of gas concentration and etch parameters such as coil rf power, dc-bias voltage to substrate, and gas pressure on etch characteristics will be systematically explored.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.390-390
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• 2012

Information technology industries has grown rapidly and demanded alternative memories for the next generation. The most popular random access memory, dynamic random-access memory (DRAM), has many advantages as a memory, but it could not meet the demands from the current of developed industries. One of highlighted alternative memories is magnetic random-access memory (MRAM). It has many advantages like low power consumption, huge storage, high operating speed, and non-volatile properties. MRAM consists of magnetic-tunnel-junction (MTJ) stack which is a key part of it and has various magnetic thin films like CoFeB, FePt, IrMn, and so on. Each magnetic thin film is difficult to be etched without any damages and react with chemical species in plasma. For improving the etching process, a high density plasma etching process was employed. Moreover, the previous etching gases were highly corrosive and dangerous. Therefore, the safety etching gases are needed to be developed. In this research, the etch characteristics of CoFeB magnetic thin films were studied by using an inductively coupled plasma reactive ion etching in $CH_4/O_2/Ar$ gas mixes. TiN thin films were used as a hardmask on CoFeB thin films. The concentrations of $O_2$ in $CH_4/O_2/Ar$ gas mix were varied, and then, the rf coil power, gas pressure, and dc-bias voltage. The etch rates and the selectivity were obtained by a surface profiler and the etch profiles were observed by a field emission scanning electron microscopy. X-ray photoelectron spectroscopy was employed to reveal the etch mechanism.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.591-593
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• 2000

In this paper, we describe the results of a combined experimental theoretical study designed to understand and predict the dielectric properties of SF$_{6}$ and SF$_{6}$+Ar mixtures. The electron transport, ionization, and attachment coefficients for pure SF$_{6}$ and gas mixtures containing SF$_{6}$ has been analysed over the E/N range 30~300[Td] by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2[%] and 0.5[%] SF$_{6}$+Ar mixtures were measured by time- of- flight method, The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with the experimental and theoretical for a rang of E/N values. Electron energy distribution functions computed from numerical solutions of the electron transport and reaction coefficients as functions of E/N. We have calculated $\alpha$,η and $\alpha$-η the ionization, attachment coefficients, effective ionization coefficients, and (E/N), the limiting breakdown electric-field to gas density ratio, in SF$_{6}$ and SF$_{6}$+Ar mixtures by numerically solving the Boltzmann equation for the electron energy distribution. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of theections of the

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.72-74
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• 2004

In this study, we used a inductively coupled plasma (ICP) source for etching $Al_2O_3$ thin films because of its high plasma density, low process pressure and easy control bias power. $Al_2O_3$ thin films were etched using $Cl_2/BCl_3$, $N_2/Cl_2/BCl_3$, and Ar/$Cl_2/BCl_3$ plasma. The experiments were carried out measuring the etch rates and the selectivities of $Al_2O_3$ to $SiO_2$ as a function of gas mixing ratio, rf power, and chamber pressure. When $Cl_2$ 50% was added to $Cl_2/BCl_3$ plasma, the etch rate of the $Al_2O_3$ films was 118 nm/min. We also investigated the effect of gas addition. In case of $N_2$ addition, the etch rate of the $Al_2O_3$ films decreased while $N_2$ was added into $Cl_2/BCl_3$ plasma. However, the etch rate increased slightly as Ar added into $Cl_2/BCl_3$ plasma, and then further increase of Ar decreased the etch rate. The maximum etch rate was 130 nm/min at Ar 20% in $Cl_2/BCl_3$ plasma, and the highest etch selectivity was 0.81 in $N_2$ 20% in $Cl_2/BCl_3$ plasma. And, we obtained the results that the etch rate increases as rf power increases and chamber pressure decreases. The characteristics of the plasmas were estimated using optical emission spectroscopy (OES).