• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.1-7
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• 2007

In this paper, two kinds of initial oxidation methods i.e., SLTO(Slow Low Temperature Oxidation: $700^{\circ}C$) and RTO(Rapid Thermal Oxidation: $850^{\circ}C$) are applied prior to the plasma nitridation for ultra thin oxide of RPNO (Remote Plasma Nitrided Oxide). It is observed that SLTO has superior characteristics to RTO such as lower SS(Sub-threshold Slope) and improved Ion-Ioff characteristics. Low frequency noise characteristics of SLTO also showed better than RTO both in linear and saturation regime. It is shown that flicker noise is dominated by carrier number fluctuation in the channel region. Therefore, SLTO is promising for nano-scale CMOS technology with ultra thin gate oxide.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.569-574
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• 2007

In this paper, the reliability (NBTI degradation: ${\Delta}V_{th}$) and device characteristic of nano-scale PMOSFET with plasma nitrided oxide (PNO) is characterized in depth by comparing those with thermally nitrided oxide (TNO). PNO case shows the reduction of gate leakage current and interface state density compared to TNO with no change of the $I_{D.sat}\;vs.\;I_{OFF}$ characteristics. Gate oxide capacitance (Cox) of PNO is larger than TNO and it increases as the N concentration increases in PNO. PNO also shows the improvement of NBTI characteristics because the nitrogen peak layer is located near the $Poly/SiO_2$ interface. However, if the nitrogen concentration in PNO oxide increases, threshold voltage degradation $({\Delta}V_{th})$ becomes more degraded by NBT stress due to the enhanced generation of the fixed oxide charges.

• Korean Journal of Materials Research
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• v.19 no.8
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• pp.421-426
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• 2009

We report on the capacitively coupled O2 plasma etching of PMMA and polycarbonate (PC) with a diffusion pump. Plasma process variables were process pressure and CCP power at 5 sccm $O_2$ gas flow rate. Characterization was done in order to analyze etch rate, etch selectivity, surface roughness, and morphology using stylus surface profilometry and scanning electron microscopy. Self bias decreased with increase of process pressure in the range of 25$\sim$180 mTorr. We found an important result for optimum pressure for the highest etch rate of PMMA and PC, which was 60 mTorr. PMMA and PC had etch rates of 0.46 and 0.28 ${\mu}m$/min under pressure conditions, respectively. More specifically, etch rates of the materials increased when the pressure changed from 25 mTorr to 60 mTorr. However, they reduced when the pressure increased further after 60 mTorr. RMS roughnesses of the etched surfaces were in the range of 2.2$\sim$2.9 nm. Etch selectivity of PMMA to a photoresist was $\sim$1.5:1 and that of PC was $\sim$0.9:1. Etch rate constant was about 0.04 ${\mu}m$/minW and 0.02 ${\mu}m$/minW for PMMA and PC, respectively, with the CCP power change at 5 sccm $O_2$ and 40 mTorr process pressure. PC had more erosion on the etched sidewall than PMMA did. The OES data showed that the intensity of the oxygen atomic peak (777.196 nm) proportionally increased with the CCP power.

• Explosives and Blasting
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• v.23 no.3
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• pp.57-74
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• 2005

In the past, explosives like dynamite was used to blast rock. However, today it is difficult to use explosives in urban blastinglike excavation for subway, building, and housing land. According to Korea Department of Construction and Transportation's proposal for blasting design manual and test blasting, from TYPE I blasting to TYPE IV blasting are recommended when we determine 0.3cm/sec(centisec) as a maximum allowable ground vibration with a distance between $25m\~120m$ from structures. This article was written to introduce one of TYPE I (reck blasting within 25m from structures) blasting method, Nano-Plasma blasting method. When Nano-Plasma blasting method is applied in urban blasting job, ground vibration (15m away from blasting point) is expected 0.1cm/sec, which is only half of a ground vibration when low ground vibration blasting method is applied. By this unique characteristic, Nano-Plasma blasting method is epochal urban blasting technique.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.694-696
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• 2011

The high enthalpy plasma research center in Chonbuk national university is under construction for four types of plasma equipments. The equipments are 1set of 0.4 MW class enhanced Huels type plasma equipment, 1 set of 2.4 MW class enhanced Huels type plasma quipment, 1 set of 60 kW RF plasma equipment and 1 set of 200 kW RF plasma equipment. 60kW RF plasma system is R&D and pilot scale production equipment of nano powder synthesis and plasma spray coating. 200kW RF plasma system is mass production equipment with high power capacity of nano powder synthesis. 0.4MW plasma system can be applied to the ground test facility for material testing under re-entry conditions for space vehicles.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.39-45
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• 2003

Nano-TiO$_2$ photocatalytic coatings were deposited on the stainless steel 304(50$\times$70$\times$3mm) by the APS(Atmospheric Plasma Spraying). Photocatlytic reaction was tested in MB(methylene blue) aqueous solution. For applying nano-TiO$_2$ powders by thermal spray, the starting nano-TiO$_2$ powder with 100% anatase crystalline was agglomerated by spray drying. Plasma second gas(H$_2$) flow rate and spraying distance were used as principal process parameters which are known to control heat enthalpy(heat input). The relationship between process parameters and the characteristics of microstructure such as the anatase phase fraction and grain size of the TiO$_2$ coatings were investigated. The photo-decomposition efficiency of TiO$_2$ coatings was evaluated by the kinetics of MB aqueous solution decomposition. It was found that the TiO$_2$ coating with a lower heat input condition had a higher anatase fraction, smaller anatase grain size and a better photo-decomposition efficiency.

• Research in Plant Disease
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• v.25 no.4
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• pp.179-187
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• 2019

This study was carried out to test the antimicrobial activities of nano metal hybrid materials produced by plasma technologies (radio frequency-thermal plasma system and direct current sputtering system) against microbes isolated from cucurbit (watermelon, pumpkin, and gourd) seeds. Eight different nano metal hybrid materials and four carriers were tested against five different fungal and ten different bacterial isolates in vitro. Among the tested nano metal hybrid material, Brass/CaCO₃ (1,000 ppm) exhibited 100% antimicrobial effect against all the five tested fungi. However, nano metal hybrid material Brass/CaCO₃ (1,000 ppm) inhibited only four bacterial isolates, Weissella sp., Rhodotorula mucilaginosa, Burkholderia sp., and Enterococcus sp. at 100% level, and did not inhibited other six bacterial isolates. Nano metal hybrid material graphite-nickel (G-Ni) showed 100% inhibition rate against Rhizopus stolonifer and 52.94-71.76% inhibition rate against four different fungal isolates. Nano metal hybrid material G-Ni did not show any inhibition effects against tested ten bacterial isolates. In summary, among the tested eight different nano metal hybrid materials and four carriers, Brass/CaCO₃ showed inhibition effects against five fungal isolates and four bacterial isolates, and G-Ni showed variable inhibition effects (52.94-100%) against five fungal isolates and did not show any inhibition effects against all the bacterial isolates.

• Transactions on Electrical and Electronic Materials
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• v.10 no.2
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• pp.35-39
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• 2009

A novel Helmholtz coil inductively coupled plasma(H-ICP) etcher is proposed and characterized for deep nano-scale CMOS technology. Various hardware tests are performed while varying key parameters such as distance between the top and bottom coils, the distance between the chamber ceiling and the wafer, and the chamber height in order to determine the optimal design of the chamber and optimal process conditions. The uniformity was significantly improved by applying the optimum conditions. The plasma density obtained with the H-ICP source was about $5{\times}10^{11}/cm^3$, and the electron temperature was about 2-3 eV. The etching selectivity for the poly-silicon gate versus the ultra-thin gate oxide was 482:1 at 10 sccm of $HeO_2$. The proposed H-ICP was successfully applied to form multiple 60-nm poly-silicon gate layers.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.1-5
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• 2011

Silicon carbide (SiC) has recently drawn an enormous industrial interest because of its useful mechanical properties such as thermal resistance, abrasion resistance and thermal conductivity at high temperature. RF Thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) has been utilized for synthesis of high purity SiC powder from cheap inorganic solution (Tetraethyl Orthosilicate, TEOS). It is found that the powders by thermal plasma consist of SiC with free carbon and amorphous silica ($SiO_2$) and, by thermal treatment and HF treatment, the impurities are driven off resulting high purity SiC nano-powder. The synthesized SiC powder lies below 30 nm and its properties such microstructure, phase composition, specific surface area and free carbon content have been characterized by X-ay diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric (TG) and Brunauer-Emmett-Teller (BET).

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.523-527
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• 2012

Silicon carbide (SiC) has recently drawn an enormous amount of industrial interest due to its useful mechanical properties, such as its thermal resistance, abrasion resistance and thermal conductivity at high temperatures. In this study, RF thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) was utilized for the synthesis of high-purity SiC powder from an organic precursor (hexamethyldisilazane, vinyltrimethoxysilane). It was found that the SiC powders obtained by the RF thermal plasma treatment included free carbon and amorphous silica ($SiO_2$). The SiC powders were further purified by a thermal treatment and a HF treatment, resulting in high-purity SiC nano-powder. The particle diameter of the synthesized SiC powder was less than 30 nm. Detailed properties of the microstructure, phase composition, and free carbon content were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), a thermogravimetric (TG) analysis, according to the and Brunauer-Emmett-Teller (BET) specific surface area from N2 isotherms at 77 K.