• 한국자기학회:학술대회 개요집
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• 한국자기학회 2012년도 임시총회 및 하계학술연구발표회
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• pp.70-71
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• 2012

In summary, the BLS experiments was applied to investigate the magnetic properties of $Co_{40}Fe_{40}B_{20}$ thin films. We find that the exchange stiffness constant decrease with increasing Ar gas pressure.

• 한국분말재료학회지
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• 제17권5호
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• pp.379-384
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• 2010

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 $m^2g^{-1}$ of specific surface area and 45.6 nm of average particles diameter.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.1-7
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• 2018

이산화주석은 리튬 이온 전지의 Anode 전극물질, 또는 $H_2$, NO, $NO_2$ 등의 가스 분자가 표면에 흡착되면 전기저항이 변하는 특성을 이용하여 가스센서로 활용되고 있으며, 나노구조를 갖는 이산화주석의 합성과 관련하여 많은 연구가 활발하게 이루어지고 있다. 나노구조물의 경우 Bulk 상태보다 체적 대비 표면적비가 높기 때문에 기체분자의 흡착확률을 높일 수 있으므로 고감도 가스 센서의 구현이 가능하고, Li-ion 이차전지의 경우에도 비정전용량을 향상시킬 수 있다. 본 연구에서는 열화학기상증착 장비를 이용하여 기상수송방법으로 $SnO_2$ 나노구조물을 Si 기판 위에 직접 성장시켰다. 이때 이송가스로 이용되는 고순도 Ar 가스에 고순도 산소가스를 혼합하였고, 산소가스의 혼합량에 따라 다른 형태의 산화주석 나노구조물이 성장되는 것을 확인하였다. 기상수송방법으로 성장된 산화주석 나노구조물의 결정학적 특성은 Raman 분광학 및 XRD 분석을 통하여 확인하였고, 표면형상을 주사전자현미경을 통하여 확인하였다. 분석결과 산화주석 나노구조물은 산소가스 혼합량에 민감하게 영향을 받았으며, 이송가스로 이용되는 고순도 Ar 1000 SCCM에 고순도 산소가스 10 SCCM을 혼합하였을 때, 적당한 두께를 가지면서 Nanodots 형태의 표면형상을 갖는 $SnO_2$ 결정상의 나노구조물이 성장되는 것을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1550-1552
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• 1999

In this study, (Ba,Sr)$TiO_3$ thin films were etched with a magnetically enhanced inductively coupled plasma (MEICP) as a function $CF_4$/Ar gas mixing ratio. Experimental was done by varying the etching parameters such as rf power, dc bias and chamber pressure. The maximum etch rate of the BST films was $1700{\AA}$/min under $CF_4/(CF_4+Ar)$ of 0.1, 600W/350V and 5 mTorr. The selectivity of BST to Pt and PR was 0.6, 0.7, respectively. X-ray photoelectron spectroscopy (XPS) studies shows that there are surface reaction between Ba, Sr, Ti and C, F radicals during the (Ba,Sr)$TiO_3$ etching. To analysis the composition of surface residue remaining after the etching, films etched with different $CF_4$/Ar gas mixing ratio were investigated using XPS.

• 한국전기전자재료학회논문지
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• 제22권12호
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• pp.1005-1008
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• 2009

In this study, adaptively coupled plasma (ACP) source was used for dry etching of $Al_2O_3$ thin film. During the etching process, the wafer surface temperature is an important parameter to influent the etching characteristics. Therefore, the experiments were carried out in ACP to measuring the etch rate, the selectivities of $Al_2O_3$ thin film to mask materials and the etch profile as functions of $Cl_2$/Ar gas ratio and substrate temperature. The highest etch rate of $Al_2O_3$ was 65.4 nm/min at 75% of $Cl_2/(Cl_2+Ar)$ gas mixing ratio. The etched profile was characterized using field effect scanning electron microscopy (FE-SEM). The chemical states of $Al_2O_3$ thin film surfaces were investigated with x-ray photoelectron spectroscopy (XPS).

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.29-32
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• 2000

Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO$_2$thin films were etched with Cl$_2$/Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$film is 230 $\AA$/min at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$to YMnO$_3$was 1.83. As a XPS analysis, the surface of etched CeO$_2$thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.285-288
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• 1997

Generally the high dielectric films, such as PZT(Pb(Z $r^{1-x}$ $Ti_{x}$ ) $O_3$) and BST(B $a_{l-x}$S $r_{x}$ Ti $O_3$) have been formed on the Pt thin films. However it is generally known that the dry etching of Pt is difficult because of its chemical stability. So, the dry etching of Pt remains at the preliminary work. Therefore, in this study, Pt etching mechanism was investigated with Ar/C $l_2$gas plasma by using XPS(X-ray photoelectron spectroscopy) and QMS(Quadrupole mass spectrometry). Ion current density was measured with Ar/C $l_2$gas plasma by using single Langmuir probe. XPS results shoved that the atomic % of Cl element on the etched Pt sample increased with increasing Ar/(Ar+C $l_2$). And QMS results showed that the increase of Ar partial pressure in the plasma resulted in the improvement of C $l_2$dissociation and Cl redical formation and simultaniously the increase of ion bombardment effects.s.s.

• Transactions on Electrical and Electronic Materials
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• 제11권3호
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• pp.116-119
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• 2010

The etching characteristics of zinc oxide (ZnO) were investigated, including the etch rate and the selectivity of ZnO in a $Cl_2/BCl_3$/Ar plasma. It was found that the ZnO etch rate, the RF power, and the gas pressure showed non-monotonic behaviors with an increasing Cl2 fraction in the $Cl_2/BCl_3$/Ar plasma, a gas mixture of $Cl_2$(3 sccm)/$BCl_3$(16 sccm)/Ar (4 sccm) resulted in a maximum ZnO etch rate of 53 nm/min and a maximum etch selectivity of 0.89 for ZnO/$SiO_2$. We used atomic force microscopy to determine the roughness of the surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the plasmas. Due to the relatively low volatility of the by-products formed during etching with $Cl_2/BCl_3$/Ar plasma, ion bombardment and physical sputtering were required to obtain the high ZnO etch rate. The chemical states of the etched surfaces were investigated using X-ray photoelectron spectroscopy (XPS). This data suggested that the ZnO etch mechanism was due to ion enhanced chemical etching.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.206-209
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• 2003

The purpose of AR and HR coating is acquire the very low reflection rate and the high reflection rate through the deposition of a thin film using the refraction ofmaterial. Basically if the high refractive material and the low refractive material are chosen and the condition for the experiment is determined, then we solve theproject with the optical design and multi thin film coating. First of all, we choose $SiO_2$for the low refractive material and $TiO_2$ for the high refractive material and apply Sputtering System easy to control the refraction rate and excellent in reconstruction to the equipment of thin film multiplication. For the control of the refraction rate and growth rate we modify RF Power and the ratio of Gas(Ar:O2), And we use Ellipsometer for estimation and analysis of the refraction rate and growth rate and AFM&SEM for the analysis of surface and component.

• 전기학회논문지P
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• 제61권1호
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• pp.13-17
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• 2012

Ionization and Attachment Coefficients in pure $CH_4$, $CF_4$ and mixtures of $CF_4$ and Ar, have been analyzed over a range of the reduced electric field strength between 0.1 and 350[Td] by the two-term approximation of the Boltzmann equation (BEq.) method and the Monte Carlo simulation (MCS). The calculations of electron swarm parameters require the knowledge of several collision cross-sections of electron beam. Thus, published momentum transfer, ionization, vibration, attachment, electronic excitation, and dissociation cross-sections of electrons for $CH_4$, $CF_4$ and Ar, were used. The results of the Boltzmann equation and the Monte Carlo simulation have been compared with the data presented by several workers. The deduced transport coefficients for electrons agree reasonably well with the experimental and simulation data obtained by Nakamura and Hayashi. The energy distribution function of electrons in $CF_4$-Ar mixtures shows the Maxwellian distribution for energy. That is, f(${\varepsilon}$) has the symmetrical shape whose axis of symmetry is a most probably energy. The proposed theoretical simulation techniques in this work will be useful to predict the fundamental process of charged particles and the breakdown properties of gas mixtures.