• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.199-203
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• 2012

A modified sol-gel method and $N_2$-plasma treatment were used to prepare bulk and surface doped N-$TiO_2$, respectively. XRD, TEM, UV-vis spectroscopy, $N_2$ adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared $TiO_2$ samples. The N doping did not change the phase composition and particle sizes of $TiO_2$ samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N-$TiO_2$ prepared by $N_2$-plasma was much higher than that of bulk doped N-$TiO_2$ prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.

• 한국재료학회지
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• 제9권5호
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• pp.496-502
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• 1999

In this study, n-GaN samples were etched using planar inductively coupled $Cl_2$/$H_2$plasmas and the effects of plasma conditions on the etch properties, surface composition, and ohmic contact formation were investigated as a function of gas combination. As the addition of hydrogen to the $Cl_2$plasma increased to 100%, GaN etch rates decreased due to the reduction of chlorine radical density. Even though the variation of the surface composition is limited under $50\AA$, the surface composition was also changed from Ga-rich to N-rich with the increased addition of hydrogen to $Cl_2$. Etch products by the reaction between Ga in GaN and Cl in $Cl_2$ plasma were investigated using OES analysis during the GaN etching. The value of specific resistivity of the contact formed on the n-GaN etched using 100% $Cl_2$plasma was 3.1$\times$10\ulcorner$\Omega$$\textrm{cm}^2$, and which was lower than that formed on the non-etched n-GaN. However, the resistively was increased with the increased hydrogen percent in $Cl_2$/$H_2$.

• 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).

• International Journal of Oral Biology
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• 제43권2호
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• pp.83-91
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• 2018

Nonthermal atmospheric plasma has been studied for its many biomedical effects, such as tooth bleaching, wound healing, and coagulation. In this study, the effects of dentinal tubules occlusion were investigated using fluoride-carboxymethyl cellulose (F-CMC) gel, nano-sized hydroxyapatite (n-HA), and nonthermal atmospheric plasma. Human dentin specimens were divided to 5 groups (group C, HA, HAF, HAP, and HAFP). Group HA was treated with n-HA, group HAF was treated with n-HA after a F-CMC gel application, group HAP was treated with n-HA after a plasma treatment and group HAFP was treated with n-HA after a plasma and F-CMC gel treatment. The occlusion of dentinal tubules was investigated using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), which shows Ca/P ratio. In the EDS results, a higher Ca/P ratio was shown in the groups including n-HA than in the control group. The specimens of group HAP and HAFP had a higher Ca/P ratio in retentivity. In the SEM results, there was not a significant difference in the amount of times applied. Therefore, this study suggests F-CMC gel and n-HA treatment using nonthermal atmospheric plasma will be a new treatment method for decreasing hypersensitivity.

• 마이크로전자및패키징학회지
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• 제26권3호
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• pp.51-57
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• 2019

구리 표면을 대기 중의 산화로부터 보호하기 위해서 아르곤(Ar)과 질소($N_2$) 가스를 이용하는 two-step플라즈마 공정으로 산화 방지층인 구리 질화물 패시베이션 형성을 연구하였다. Ar 플라즈마는 구리 표면에 존재하는 이물질을 제거하는 동시에 표면을 활성화시켜 다음 단계에서 진행되는 $N_2$ 플라즈마 공정 시 질소 원자와 구리의 반응을 촉진시키는 역할을 수행한다. 본 연구에서는 two-step 플라즈마 공정 중 Ar 플라즈마 공정 조건이 구리 질화물 패시베이션 형성에 미치는 영향을 실험계획법의 완전요인설계를 통하여 분석하였다. XPS 분석에 의하면 Ar 플라즈마 공정 시 낮은 RF 파워와 압력을 사용할 경우 구리 산화물 피크(peak) 면적은 감소하고, 반대로 구리 질화물(Cu4N, Cu3N) 피크 면적은 증가하였다. Ar 플라즈마 공정 시 구리 질화물 형성의 주 효과는 RF 파워로 나타났으며 플라즈마 공정 변수간 교호작용은 거의 없었다.

• 한국표면공학회지
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• 제40권6호
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• pp.250-253
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• 2007

Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 11 steel. Plasma nitrocarburizing was conducted for 12 h at $520^{\circ}C$ in the nitrogen, hydrogen and methane atmosphere to produce the $\varepsilon-Fe_{2-3}(N,C)$ phase. It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of $\varepsilon-phase$, with a small proportion of $\gamma'-Fe_4(N,C)$ phase. The thickness of the compound layer was about $5{\mu}m$ and the diffusion layer was about $150{\mu}m$ in thickness, respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of $500^{\circ}C$ for 1 hour. The very thin magnetite($Fe_3O_4$) layer $1-2{\mu}m$ in thickness on top of the compound layer was obtained by plasma post oxidation. It was confirmed that the corrosion characteristics of the nitrocarburized compound layer could be further improved by the application of the superficial magnetite layer.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.163-163
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• 2003

TiN barrier막 위에 metal organic chemical deposition(MOCVD)법으로 RuO$_2$ 를 증착시 TiN막 표면을 세정처리하지 않을 경우 RuO$_2$의 핵생성이 어렵고, 그로 인해 RuO$_2$ 연속막이 형성되기 힘들다. 그러므로 RuO$_2$의 핵생성을 향상시키기 위해 TiN막에 대한 전처리 세정이 필수적이다. TiN막의 전처리 세정방법으로 ECR plasma 세정법을 사용하였으며, $O_2$ plasma와 H$_2$ plasma 그리고 Ai plasma를 이용해 각각의 exposure time을 변화시키며 전처리 세정을 실시하였다. H$_2$ plasma와Ar plasma의 exposure time이 증가됨에 따라 RuO$_2$의 핵생성이 향상되었다. 본 연구에서는 scanning electron microscopy(SEM), Auger electron emission spectrometry(AES), Atomic Force Microscope(AFM), X-ray diffraction (XRD) 등의 분석을 통해 TiN막 표면에 대한 ECR plasma 전처리 세정 이 RuO$_2$의 핵생성과 연속막 성장에 미치는 효과에 대해 조사하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.136.1-136.1
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• 2015

In the present study, UHF (320 MHz) in combination with RF (13.56 MHz) plasmas was used for the synthesis of hydrogenated silicon nitride (SiNx:H) films by PECVD process at low temperature. RF/UHF hybrid plasmas were maintained at a fixed pressure of 410 mTorr in the N2/SiH4 and N2/SiH4/NH3 atmospheres. To investigate the radical generation and plasma formation and their control for the growth of the film, plasma diagnostic tools like vacuum ultraviolet absorption spectroscopy (VUVAS), optical emission spectroscopy (OES), and RF compensated Langmuir probe (LP) were utilized. Utilization of RF/UHF hybrid plasmas enables very high plasma densities ~ 1011 cm-3 with low electron temperature. Measurements using VUVAS reveal the UHF source is quite effective in the dissociation of the N2 gas to generate more active atomic N. It results in the enhancement of the Si-N bond concentration in the film. Consequently, the deposition rate has been significantly improved up to 2nm/s for the high rate synthesis of highly transparent (up to 90 %) SiNx:H film. The films properties such as optical transmittance and chemical composition are investigated using different analysis tools.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.93-94
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• 2005

본 연구에서는 저온 공정에서 제작되는 소자에의 응용을 위하여 Inductively Coupled Plasma Chemical Vapor Deposition(ICP-CVD) 내에서 $N_2O$ 기체를 활용한 plasma oxidation을 통한 silicon 표면의 oxynitridation과 이로부터 tunnel gate dielectirics로 사용될 SiON 층을 형성하였으며, 형성된 SiOxNy 층의 전기적 특성을 측정하여 tunnel gate dielectrics로서 효과적인 기능을 수행함을 확인하였다. 형성된 박막의 성분 분석을 위하여 energy dispersive spectroscopy(EDS)를 이용하여 SiOxNy 층의 생성을 확인하였으며, 전기적인 특성을 통하여 tunnel gate dielectrics의 기능을 수행함을 알 수 있었다. 형성된 SiOxNy 층은 초박막 형태임에도 절연막으로서의 기능을 나타내었다.

• 한국진공학회지
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• 제10권2호
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• pp.234-240
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• 2001

본 연구에서는 Mg을 첨가한 Cu-alloy에 의해 TiN의 확산방지능력을 향상시키고자 하였다. Cu(Mg) 박막은 대기노출시킨 TiN박막위에 증착되었으며 열처리시 Cu 박막내의 Mg은 TiN의 표면에 있는 산소와 반응하여 매우 얇은(~100 $\AA$) MgO를 형성하게되고 MgO에 의해 TiN의 확산방지능력은 Cu(4.5 at.%Mg)의 경우 $800^{\circ}C$까지 향상됨을 알 수 있었다. 그러나 Cu(Mg) a]toy는 TiN위에서 접착특성이 좋지 않기 때문에 TiN을 $O_2$plasma 처리하였으며 $O_2$ plasma 처리후 $300^{\circ}C$ 진공열처리를 통해 접착력이 크게 향상되는 것을 알 수 있었다. 이는 $O_2$ plasma 처리에 의해 TiN표면에 Mg과 반응할 수 있는 산소의 양이 증가하는 데 기인하며 이에 따라 Mg의 계면이동이 크게 증가되어 치밀한 MgO가 형성됨을 확인하였다. 그리고 $O_2$ plasma 처리시 RF power를 증가시키면 계면으로 이동하는 Mg의 양이 오히려 감소하였고 이것은 TiN의 표면이 $TiO_2$로 변하여 Mg과 결합할 수 있는 산소의 양이 상대적으로 감소하였기 때문인 것으로 생각된다. 또한 접착층으로서 Si을 50$\AA$ 증착하여 접착력을 크게 향상시켰으며 Si 증착에 의한 TiN의 확산방지능력은 감소되지 않는 것을 알 수 있었다.