• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.461-476
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• 2014

Continuous Water-Soluble Organic Carbons (WSOC) by the Particle Into Liquid Sampler - Total Organic Carbon (PILS-TOC) analyzer were measured at the Seoul intensive monitoring site from June 17 through July 5 in 2014. In addition, the 24 hour integrated PM2.5 collected by Teflon and Quartz filters were analyzed for water soluble ions by Ion chromatography (IC), WSOC by TOC from water extracts, organic carbon (OC), elemental carbon (EC) by carbon analyzer using the thermal optical transmittance (TOT) method, and mass fragment ions (m/z) related to alkanes and PAHs (Poly Aromatic Hydrocarbons) by Gas Chromatography-Mass Spectrometer-Thermal Desorption (GC/MS-TD). Based on the statistical analysis, four different Carbonaceous Thermal Distributions (CTDs) from OCEC thermal-gram were identified. This study discusses the primary and secondary sources of WSOC based on the Classified CTD, organic mass fragments, and diurnal patterns of WSOC. The results provide knowledge regarding the origins of WSOC and their behaviors.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.188.1-188.1
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• 2014

Aluminum is widely used as a material for electrode on silicon based devices. Especially, aluminum films are used as backside and front-side electrodes in silicon quantum dot (QD) solar cells. In this point, the diffusion of aluminum is very important for the enhancement of power conversion efficiency by improvement of contact property. Aluminum was deposited on a Si (100) wafer and a Si QD layer by ion beam sputter system with a DC ion gun. The Si QD layer was fabricated by $1100^{\circ}C$ annealing of the $SiO_2/SiO_1$ multilayer film grown by ion beam sputtering deposition. Cs ion beam with a low energy and a grazing incidence angle was used in SIMS depth profiling analysis to obtain high depth resolution. Diffusion behavior of aluminum in the Al/Si and Al/Si QD interfaces was investigated by secondary ion mass spectrometry (SIMS) as a function of heat treatment temperature. It was found that aluminum is diffused into Si substrate at $450^{\circ}C$. In this presentation, the effect of heat treatment temperature and Si nitride diffusion barrier on the diffusion of Al will be discussed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.10
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• pp.1-10
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• 2000

A rigorous modeling of ultra-low energy implantation is becoming increasingly more important as devices shrink to deep submicron dimensions. In this paper, we have developed an efficient three-dimensional Monte Carlo ion implantation model based on a modified Binary Collision Approximation(BCA). To this purpose, the modified electronic stopping model and the multi-body collision model have been taken into account in this simulator. The dopant and damage profiles show very good agreement with SIMS(Secondary Ion Mass Spectroscopy) data and RBS(Rutherford Backscattering Spectroscopy) data, respectively. Moreover, the ion distribution replica method has been implemented into the model to get a computational efficiency in a 3D simulation, and we have calculated the 3D Monte Carlo simulation into the topographically complex structure.

• Korean Journal of Materials Research
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• v.8 no.3
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• pp.268-273
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• 1998

Standard Zircaloy-4 sheets, charged with 230-250ppm hydrogen by the gas-charging method and homogenized at $400^{\circ}C$ for 72hrs in a vacuum, were corroded in pure water and aqueous LiOH solutions using static autoclaves at $350^{\circ}C$. Their corrosion behaviors were characterized by measuring their weight gains with the corrosion time and observing their microstructures using an optical microscope and a scanning electron microscope. The elemental depth profiles for hydrogen and lithium were measured using a secondary ion mass spectrometry(S1MS) to confirm their distributions at the oxidelmetal interface. The normal Zircaloy-4 specimens corroded abruptly and heavily at the concentration of Li ions more than 30ppm in the aqueous solution. This is due to accelerations by the rapid oxidation of many Zr- hydrides formed by the large amount of absorbed hydrogen, resulting from the increased substitution of $Li^{+}$ ions with $Zr^{4+}$-sites in the oxide as the Li ion concentration increased. The specimens that had been charged with amounts of hydrogen greater than its solubility corroded early with a more rapid acceleration than normal specimens, regardless of the corrosion solutions. At longer corrosion times. however, normal specimens showed a rather accelerated corrosion rate compared to the hydrogen-charged specimens. These slower corrosion rates of the hydrogen-charged specimens at the longer corrosion times would be due to the pre-existent Zr-hydride in the matrix, which causes the hydrogen pick- up into the specimen to be depressed, when the oxide with an appropriate thickness formed.

• 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 Navigation and Port Research Conference
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• 2000.11a
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• pp.21-24
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• 2000

Ferroelectric YMnO$_3$thin films are excellent dielectric materials for high integrated ferroelectric random access memory (FRAM) with metal-ferroelectric-silicon field effect transistor (MFSFET) structure. In this study, YMnO$_3$thin films were etched with Cl$_2$/Ar gas chemistries in inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$thin films is 285 $\AA$/min under Cl$_2$/Ar of 10/0, 600 W/-200 V and 15 mTorr. The selectivities of YMnO$_3$over CeO$_2$and $Y_2$O$_3$are 2.85, 1.72, respectively. The results of x-ray photoelectron spectroscopy (XPS) reflect that Y is removed dominantly by chemical reaction between Y and Cl, while Mn is removed more effective by Ar ion bombardment than chemical reaction. The results of secondary ion mass spectrometer (SIMS) were equal to these of XPS. The etch profile of the etched YMnO$_3$film is approximately 65$^{\circ}$and free of residues at the sidewall.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.996-1002
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• 2000

Ferroelectric (Ba, Sr) TiO$_3$(BST) thin films have attracted much attention for use in new capacitor materials of dynamic random access memories (DRAMs). In order to apply BST to the DRAMs, the etching process for BST thin film with high etch rate and vertical profile must be developed. However, the former studies have the problem of low etch rate. In this study, in order to increase the etch rate, BST thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP) that have much higher plasma density than RIE (reactive ion etching) and ICP (inductively coupled plasma). Experiment was done by varying the etching parameters such as CF$_4$/(CF$_4$+Ar) gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 170nm/min under CF$_4$/CF$_4$+Ar) of 0.1, 600 W/-350 V and 5 mTorr. The selectivities of BST to Pt and PR were 0.6 and 0.7, respectively. Chemical reaction and residue of the etched surface were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.84-87
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• 2001

In this study, $CeO_2$ thin films were etched with a $CF_4/Ar$ gas combination in inductively coupled plasma (ICP), The maximum etch rate of $CeO_2$ thin films is $270{\AA}/min$under $CF_4/(CF_4+Ar)$ of 0.2, 600 W/-200 V, 15 mTorr, and $25^{\circ}C$. The selectivities of $CeO_2$ to PR and SBT are 0.21, 0.25. respectively. The surface reaction of the etched $CeO_2$ thin films was investigated with x-ray photoelectron spectroscopy (XPS). There is a chemical reaction between Ce and F, Compounds such as $Ce-F_x$ are remains on the surface of $CeO_2$ thin films. Those products can be removed by Ar ion bombardment effect, The results of secondary ion mass spectrometer (SIMS) were equal to these of XPS. Scanning electron microscopy (SEM) was used to examine etched profiles of $Ce-F_x$ thin films. The etch profile of over-etched $CeO_2$ films with the $0.5 {\mu}m$ line was approximately $65^{\circ}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.12-16
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• 2001

We investigated the etching characteristics of $YMnO_3$ thin films in high-density plasma etching system. In this study. $YMnO_3$ thin films were etched with $CF_{4}/Ar$ gas chemistries in inductively coupled plasma (ICP). Etch rates of $YMnO_3$ were measured according to gas mixing ratios. The maximum etch rate of $YMnO_3$ is 18 nm/min at $CF_{4}/(CF_{4}+Ar)$ of 20%. In optical emission spectroscopy (OES) analysis, F radical and Ar* ions in plasma at various gas chemistries decreased with increasing $CF_4$ content. Chemical states of $YMnO_3$ films exposed in plasma were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). There is a chemical reaction between metal (Y, Mn) and F and metal-fluorides were removed effectively by Ar ion sputtering. $YF_x$, $MnF_x$ such as YF, $YF_2$, $YF_3$ and $MnF_3$ Were detected using SIMS analysis. The etch slope is about $65^{\circ}C$ and free of residues.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.11
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• pp.933-938
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• 2002

(Ba,Sr)TiO$_{4}$ (BST) thin films on Pt/Ti/SiO$_{2}$/Si substrates were deposited by a sol-gel method and the etch characteristics of BST thin films have been investigated as a function of gas mixing ratio. The maximum etch rate of the BST films was 440 $AA$/min under such conditions as: CF$_{4}$(CF$_{4}$＋Ar) of 0.2, RF-power of 700 W, DC-bias voltage of -200 V, pressure of 15 mTorr and substrate temperature of 30 $^{circ}C$. The selectivities of BST to Pt, SiO$_{2}$ and PR were 0.38, 0.25 and 0.09, respectively. In the XPS (X-ray photoelectron spectroscopy) analysis, Barium (Ba) and Strontium (Sr) component in BST thin films formed low volatile compounds such as BaFx, SrFx, which are forms by the chemical reaction with F atoms and is removed by Ar ion bombardment. Titanium (Ti) is removed by chemical reaction such as TiF with ease. The result of secondary ion mass spectrometry (SIMS) analysis confirmed the existence of the BaFx, SrFK, TiFx.