• The Korean Journal of Ceramics
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• v.3 no.3
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• pp.213-217
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• 1997

In this paper, the imparct of X-ray and plasma process-induced-damages to La doped Lead Zirconate Titanate (PLZT, (Pb1-xLa)(Zr0.5Ti0.5)O3) capacitor characteristics have been investigated from the viewpoint of gigabit scale dynamic random access memory (DRAM) applications. Plamsa damage causes asymmetric degradation on hysteresis characteristics of PLZT films. On the other hand, X-ray damage results in a symmetrical reduction of charge storage densities (Qc's) for both polarities. As La concentration increases in the films, the radiation hardness of PLZT films on X-ray and plasma exposures is improved. It is observed that the damaged devices are fully recovered by thermal annealing under oxygen ambient.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.8
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• pp.711-714
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• 2008

Metal-oxide-semiconductor (MOS) capacitors were fabricated to investigate the plasma damage caused by reactive ion etching (RIE) on (100) oriented silicon-on-insulator (SOI) substrates. The thickness of the top-gate oxide, SOI, and buried oxide layers were 10 nm, 50 nm, and 100 nm, respectively. The MOS/SOI capacitors with an etch-damaged SOI layer were characterized by capacitance-voltage (C-V) measurements and compared to the sacrificial oxidation treated samples and the reference samples without etching. The measured C-V curves were compared to the numerical results from corresponding 2-dimensional (2-D) structures by using a Silvaco Atlas simulator.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.121.1-121.1
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• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.7-10
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• 2014

This study was designed to evaluate the protective effect of silkworm hemolymph against ${\gamma}-irradiation$ induced damage in the liver of mice. Female Balb/C mice (6 weeks old) were exposed to ${\gamma}-irradiation$ (6 Gy) and administered orally to silkworm hemolymph ($5ml\;kg^{-1}$ BW) for 7 days post-irradiation. The body weight, spleen index, plasma aspartate transaminase (AST), plasma alanine transaminase (ALT), and liver malondialdehyde (MDA) levels were determined. Compared with irradiated control mice, the activity of plasma AST and the level of MDA were significantly decreased in mice treated silkworm hemolymph. These results show that silkworm hemolymph is found to have a protective effect against ${\gamma}-irradiation$ induced damage in mice.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.206-210
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• 2016

Background: Ionizing radiation causes cellular damage and death through the direct damage and/or indirectly the production of ROS, which induces oxidative stress. This study was designed to evaluate the in vivo radioprotective effects of a bio-active material coated fabric (BMCF) against ${\gamma}$-irradiation-induced cellular damage in Sprague-Dawley (SD) rats. Materials and Methods: Healthy male SD rats wore bio-active material coated (concentrations in 10% and 30%) fabric for 7 days after 3 Gy of ${\gamma}$-irradiation. Radioprotective effects were evaluated by performing various biochemical assays including spleen and thymus index, WBC count, hepatic damage marker enzymes [aspartate transaminase (AST) and alanine transaminase (ALT)] in plasma, liver antioxidant enzymes, and mitochondrial activity in muscle. Results and Discussions: Exposure to ${\gamma}$-irradiation resulted in hepatocellular and immune systemic damage. Gamma-irradiation induced decreases in antioxidant enzymes. However, wearing the BMCF-30% decreased significantly AST and ALT activities in plasma. Furthermore, wearing the BMCF-30% increased SOD (superoxide dismutase) and mitochondrial activity. Conclusion: These results suggest that wearing BMCF offers effective radioprotection against ${\gamma}$-irradiation-induced cellular damage in SD rats.

• Journal of Nutrition and Health
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• v.35 no.2
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• pp.213-222
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• 2002

The alkaline comet assay has been used with increasing popularity to investigate the level of DNA damage in biomonitoring studies within the last decade in Western countries. The purpose of this study was to evaluate the usefulness of the alkaline comet assay as a biomarker of oxidative DNA damage for monitoring in the Korean population, and also to evaluate the effect of nutritional status and lifestyle factors on H2O2 induced oxidative DNA damage measured by the alkaline comet assay in human lymphocytes. The study population consisted of 61 healthy Korean male volunteers, aged 20-28. Epidemiological background data including dietary habits, smoking habits and anthropometrical measurements were collected through personal interviews. After blood collection, the comet assay in peripheral lymphocytes and plasma lipids analysis was carried out and the results analyzed. Tail moment (TM) and tail length (TL) of the comet assay were use\ulcorner to measure DNA damage in the lymphocytes of the subjects. Statistically significant (p < 0.05) positive correlations were observed between DNA damage (TM or TL) and smoking habits expressed as cigarettes smoked per day and pack years (r = 0.311 and 0.382 for TM, r = 0.294 and 0.350 for TL, respectively). There were also significant positive correlations between DNA damage parameter and waist-hip ratio. Higher plasma triglyceride levels were associated with increased damage to DNA. There were no correlations between the consumption frequencies of vegetables and DNA damage to the subjects. However, consumption frequencies of fruit and fruit juice intake were inversely associated with the TM and TL. The results indicate that die comet assay is a simple, rapid and sensitive method for detecting lymphocyte DNA damage induced by cigarette smoking. Consumption of fruit or fruit juices could potentiall modify the damaged DNA in the human peripheral lymphocytes of young Korean men.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.338-344
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• 1996

This study was an investigation of plasma-induced damages on silicon substrate in the semiconductor manufacturing technology. The plasma-induced damage level on silicon substrate was analyzed and compared in various plasma etching systems. The analysis methods were therma wave, life-time recovery, SCA (Surface Charge Analyzer) and TRXF (Total Reflection X-ray Fluorescence) measurements, and the measured values were compared for each systems. In the comparison of the values which were obtained by a system that had low life-time recovery, there was not any differences in DC parameters. However, the reflesh time distribution of device of that system had decreased about 10 to 20m sec compared to a system which had high life-time recovery.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1323-1324
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• 2008

We developed the Hyper-thermal Neutral Beam (HNB) sputtering process as a plasma damage free process for ITO top anode deposition on inverted Top emission OLED (ITOLED). For examining the effect of the HNB sputtering system, Inverted Bottom emission OLEDs (IBOLED) with ITO top anode electrode were fabricated; the characteristics of IBOLED using HNB sputtering process shows significant suppression of plasma induced damage.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.35-39
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• 2019

Effect of Ge₂Sb₂Te₅ (GST) chalcogen composition on plasma induced damage was investigated by using Ar ions and F radicals. Experiments were carried out with three different modes; the physical etching, the chemical etching, and the ion-enhanced chemical etching mode. For the physical etching by Ar ions, the sputtering yield was obtained according to ion bombarding energy and there was no change in GST composition ratio. In the plasma mode, the lowest etch rate was measured at the same applied power and there was also no plasma induced damage. In the ion-enhanced chemical etching conditions irradiated with high energy ions and F halogen radicals, the GST composition ratio was changed according to the density of F radicals, resulting in higher roughness of the etched surface. The change of GST composition ratio in halogen plasma is caused by the volatility difference of GST-halogen compounds with high energy ions over than the activation energy of surface reactions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.463-463
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• 2012

ITRS (international technology roadmap for semiconductors)에 따르면 MOS(metal-oxide-semiconductor)의 CD (critical dimension)가 45 nm node이하로 줄어들면서 poly-Si/$SiO_2$를 대체할 수 있는 poly-Si/metal gate/high-k dielectric이 대두된다고 보고하고 있다. 일반적으로 high-k dielectric를 식각시 anisotropic 한 식각 형상을 형성시키기 위해서 plasma를 이용한 RIE (reactive ion etching)를 사용하고 있지만 PIDs (plasma induced damages)의 하나인 PIED (plasma induced edge damage)의 발생이 문제가 되고 있다. PIED의 원인으로 plasma의 direct interaction을 발생시켜 gate oxide의 edge에 trap을 형성시키므로 그 결과 소자 특성 저하가 보고되고 있다. 그러므로 본 연구에서는 이에 차세대 MOS의 high-k dielectric의 식각공정에 HDP (high density plasma)의 ICP (inductively coupled plasma) source를 이용한 원자층 식각 장비를 사용하여 PIED를 줄일 수 있는 새로운 식각 공정에 대한 연구를 하였다. One-monolayer 식각을 위한 1 cycle의 원자층 식각은 총 4 steps으로 구성 되어 있다. 첫 번째 step은 Langmuir isotherm에 의하여 표면에 highly reactant atoms이나 molecules을 chemically adsorption을 시킨다. 두 번째 step은 purge 시킨다. 세 번째 step은 ion source를 이용하여 발생시킨 Ar low energetic beam으로 표면에 chemically adsorbed compounds를 desorption 시킨다. 네 번째 step은 purge 시킨다. 결과적으로 self limited 한 식각이 이루어짐을 볼 수 있었다. 실제 공정을 MOS의 high-k dielectric에 적용시켜 metal gate/high-k dielectric CMOSFETs의 NCSU (North Carolina State University) CVC model로 구한 EOT (equivalent oxide thickness)는 변화가 없으면서 mos parameter인 Ion/Ioff ratio의 증가를 볼 수 있었다. 그 원인으로 XPS (X-ray photoelectron spectroscopy)로 gate oxide의 atomic percentage의 분석 결과 식각 중 발생하는 gate oxide의 edge에 trap의 감소로 기인함을 확인할 수 있었다.