• Journal of the Korean Ceramic Society
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• 제38권6호
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• pp.587-592
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• 2001

난소결성의 TiN에 방전 플라즈마 소결법을 적용하여 고밀도 TiN 소결체를 제조하였다. 제조된 TiN 시편의 소결특성 및 입성장 정도를 평가하였으며, 전자현미경을 이용하여 미세구조를 분석하였다. Milling 과정동안 잠입된 $Al_2$O$_3$는 1$700^{\circ}C$ 이상의 소결온도에서 TiN 분말과 반응하여 부분적으로 액상을 형성하여 물질이동을 가속화함으로써 치밀화가 저온에서 시작하도록 함으로써 궁극적으로 결정립성장 제어에 기여하는 것으로 확인되었다. 이러한 현상은 굽어진 TiN 결정입계와 결정입계 삼중점에 존재하는 $Al_2$O$_3$를 포함하는 2차 결정상 cluster의 존재로 설명되어진다.

• Transactions on Electrical and Electronic Materials
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• 제13권1호
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• pp.6-9
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• 2012

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity to $SiO_2$) of ZnO thin films in $N_2/Cl_2$/Ar inductivity coupled plasma. A maximum etch rate and selectivity of 108.8 nm/min and, 3.21, respectively, was obtained for ZnO thin film at a $N_2/Cl_2$/Ar gas mixing ratio of 15:16:4 sccm. The plasmas were characterized by optical emission spectroscopy. The x-ray photoelectron spectroscopy analysis showed the efficient destruction of oxide bonds by ion bombardment. An accumulation of low volatile reaction products on the etched surface was also shown. Based on this data, an ion-assisted chemical reaction is proposed as the main etch mechanism for plasmas containing $Cl_2$.

• Journal of Environmental Science International
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• 제22권12호
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• pp.1561-1569
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• 2013

This study carried out a laboratory scale plasma reactor about the characteristics of chemically oxidative species (${\cdot}OH$, $H_2O_2$ and $O_3$) produced in dielectric barrier discharge plasma. It was studied the influence of various parameters such as gas type, $1^{st}$ voltage, oxygen flow rate, electric conductivity and pH of solution for the generation of the oxidant. $H_2O_2$ and $O_3$.) $H_2O_2$ and $O_3$ was measured by direct assay using absorption spectrophotometry. OH radical was measured indirectly by measuring the degradation of the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical). The experimental results showed that the effect of influent gases on RNO degradation was ranked in the following order: oxygen > air >> argon. The optimum $1^{st}$ voltage for RNO degradation were 90 V. As the increased of $1^{st}$ voltage, generated $H_2O_2$ and $O_3$ concentration were increased. The intensity of the UV light emitted from oxygen-plasma discharge was lower than that of the sun light. The generated hydrogen peroxide concentration and ozone concentration was not high. Therefore it is suggested that the main mechanism of oxidation of the oxygen-plasma process is OH radical. The conductivity of the solution did not affected the generation of oxidative species. The higher pH, the lower $H_2O_2$ and $O_3$ generation were observed. However, RNO degradation was not varied with the change of the solution pH.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제24권1호
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• pp.41-45
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• 2014

We have investigated the passivation property of $SiN_x$ and $SiO_2$ thin films formed using various process conditions for the application of crystalline Si solar cells. An increase in the thickness of $SiN_x$ deposited using plasma enhanced chemical vapor deposition (PECVD) led to the improvement of passivation quality. This could be associated with the passivation of Si dangling bonds by hydrogen atoms which were supplied during PECVD deposition. The $SiO_2$ thin films grown using dry oxidation process exhibited better passivation behavior than those using wet oxidation process, implying the dry oxidation process was more effective in the formation of high quality $SiO_2$ thin films. The relative effective life time gradually decreased with increasing dry oxidation temperature. Such a degradation of passivation behavior could be attributed to the increase in interface trap density caused by thermal damages.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제19권3호
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• pp.699-706
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• 2018

The permeation properties of plasma polymer membranes were studied for permanent gases such as He, $H_2$, $O_2$, $N_2$, $CH_4$ and condensable vapors such as $CO_2$, $C_2H_4$, $C_3H_8$. The plasma polymers were prepared by the discharge of microwave or radiofrequency(RF) wave. Hexamethyldisiloxane (HMDS) vapor was used as a monomer for plasma polymerization. In HMDS plasma-polymerized membranes prepared under microwave discharge, the permeability coefficient was dependent of the kinetic molecular diameter of the permeate gases. Additionally the membranes showed higher $O_2/N_2$ permselectivity compared to the plasma polymers from radiofrequency discharge. On the contrary, in the HMDS plasma-polymerized membranes prepared under radiofrequency discharge, the permeability coefficient was dependent of the critical temperature of the permeant gases. The membranes showed high selectivities of $C_2H_4$ and $C_3H_8$ over $N_2$. The permeability coefficient of plasma polymerized membranes prepared under microwave discharge was dependent of the molecular diameter of permeant gases because of high crosslinking density of the membrane. However, the crosslinking density of the plasma polymerized membranes prepared under RF discharge was lower because the energy density of RF wave is weaker than that of microwave. Hence, the permeability of RF plasma polymerized membranes became dependent of the critical temperature rather than molecular diameter of the gases.

• Journal of the Korea Organic Resources Recycling Association
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• 제31권3호
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• pp.43-53
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• 2023

This batch experiment evaluated the impacts of major plant nutrient releases by applying the modified Hyperbola model on the leachates and N₂O emissions from incorporated rice hull biochar with organic fertilizer materials. The treatments consisted of the control as incorporated with organic fertilizer materials, the incorporated rice hull biochar with organic fertilizer materials, and the incorporated plasma-activated rice hull biochar with organic fertilizer materials under redox conditions. The results indicated that the maximum release amount of NH₄-N was 3486.3 mg L^-1 in the control, and their reduction rates of NH₄-N, NO₃-N, PO₄-P, and K were 8.0%, 17.5% 44.3.0% and 8.7%, respectively, relative to the control. In the control, the highest soluble amount of PO₄-P was 681.0 mg L^-1. The estimations for accumulated NH₄-N, NO₃-N, PO₄-P, and K-releases in all the treatments were significantly (p<0.01) fitted with a modified Hyperbola model. For greenhouse gas emissions, the lowest cumulative N₂O was 340.4 mg kg^-1 in the soil incorporated with plasma-activated rice hull biochar, and the reduction rates were 27.8% and 86.4% in the rice hull biochar and plasma-activated rice hull biochar treatments, respectively, compared to the control. Therefore, it concluded that the incorporated rice hull biochar can be especially useful for controlling PO₄-P release and N₂O emissions for bio-fertilizer applications.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.489-489
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• 2012

The vibrational distribution of $N_2$ (B, v') in after-glows in $N_2$ RF flowing plasma was investigated. The optical emission of the after-glow was studied as function of distance from plasma. In a tube 2.1 cm, the gas pressure varied 8 Torr with 1000sccm nitrogen gas flowing late.. The discharges were excited by two ring-electrode powered by RF 13.56 MHz 100 Watt. $N_2$ (B, v') vibrational distribution was analyzed to see depends of position in after-glow. Dissociation rate of $N_2$ varied showing maximum in the late after-glow region. We studied $N_2$ RF capacitive flowing plasmas and afterglows by emission spectroscopy and by NO titration to determine the density of N-atoms.

• Journal of the Korean institute of surface engineering
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• 제29권6호
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• pp.834-838
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• 1996

The diagnosis of the plasma in the facing targets sputtering system was performed in mixture gas of Ar 0.18-0.0 Pa, Xe 0.0-0.18 Pa and $O_2$ 0.02 Pa by using Langmiur's probe and the effect of plasma-damage to surface smoothness and magnetic characteristics of Ba ferrite films was clarified. The electron density $N_e$ and the electron temperature $T_e$ were evaluated at the center of the plasma and at the neighborhood of the anode ring. $T_e$ decreased and $N_e$ increased with increase of $P_{Xe}$ at the center of plasma. For the measurement at the neighborhood of the anode ring, $T_e$ was almost constant and $N_e$ took the minimum value at $P_{Xe}$ of 0.1 Pa, where Ba ferrite films with excellent c-axis orientation and magnetic characteristics were obtained. It was suggested that the restriction of the bombardment of recoiled particles as well as the suppress of plasma-damage were effective for obtaining good surface smoothness and excellent magnetic characteristics and it was useful for decreasing the crystallization temperature of Ba ferrite films.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.107-107
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• 2016

TiCrAlSiN films were developed in order to improve the high-temperature oxidation resistance, corrosion resistance, and mechanical properties of conventional TiN films that are widely used as hard films to protect and increase the lifetime and performance of cutting tools or die molds. In this study, a nano-multilayered TiAlCrSiN film was deposited by cathodic arc plasma deposition. It displayed relatively good oxidation resistance at $700-900^{\circ}C$, owing to the formation protective oxides of $Al_2O_3$, $Cr_2O_3$, and $SiO_2$, and semiprotective $TiO_2$. At $1000^{\circ}C$, the increased temperature led to the formation of the imperfect oxide scale that consisted primarily of the outer ($TiO_2$,$Al_2O_3$)-mixed scale and inner ($TiO_2$, $Al_2O_3$, $Cr_2O_3$)-mixed scale.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.254-254
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• 2016

Tin dioxide (SnO2) thin film is one of the most important n-type semiconducting materials having a high transparency and chemical stability. Due to their favorable properties, it has been widely used as a base materials in the transparent conducting substrates, gas sensors, and other various electronic applications. Up to now, SnO2 thin film has been extensively studied by a various deposition techniques such as RF magnetron sputtering, sol-gel process, a solution process, pulsed laser deposition (PLD), chemical vapor deposition (CVD), and atomic layer deposition (ALD) [1-6]. Among them, ALD or plasma-enhanced ALD (PEALD) has recently been focused in diverse applications due to its inherent capability for nanotechnologies. SnO2 thin films can be prepared by ALD or PEALD using halide precursors or using various metal-organic (MO) precursors. In the literature, there are many reports on the ALD and PEALD processes for depositing SnO2 thin films using MO precursors [7-8]. However, only ALD-SnO2 processes has been reported for halide precursors and PEALD-SnO2 process has not been reported yet. Herein, therefore, we report the first PEALD process of SnO2 thin films using SnCl4 and oxygen plasma. In this work, the growth kinetics of PEALD-SnO2 as well as their physical and chemical properties were systemically investigated. Moreover, some promising applications of this process will be shown at the end of presentation.