• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.224-227
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• 2007

The reconstruction characteristics of MgO (111) textured protective layer by over-frequency accelerated discharge in AC-PDP were investigated and correlated to the variations of electronic structures. The reconstruction process and exaggerated grain growth (EGG) were explained by defect-assisted 2-D nucleation and growth mechanism combined with charged cluster model.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.41-42
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• 2015

폴리머 기판상 밀착력 향상과 증착되는 금속 박막의 전기적 특성 향상에 대한 연구를 수행하였다. 박막의 밀착력 향상을 위해 선형이온소스를 이용하여 폴리머 기판의 표면에너지 증대를 도모하였다. 폴리머 기판의 표면에너지 제어를 통해 증착된 박막의 밀착력 평가는 테이프 테스팅법을 적용하였고 전처리 전후 밀착력이 향상됨을 확인하였다. 또한 일반적인 마그네트론 스퍼터링의 경우 상온에서 증착되는 금속 박막의 결정성이 낮다는 한계점을 극복하기 위해, 플라즈마 보조 마그네트론 스퍼터링 방법을 적용하여 증착되는 박막의 결정성 향상을 통해 증착된 Cu 박막의 전기적 특성 향상을 얻을 수 있었다. 박막의 결정성 향상을 통해 전기적 특성은 10% 이상 향상됨을 확인하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.18-22
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• 2000

An experimental study was carried out to investigate the effect of nano-contact condition on the nano-adhesion phenomena. SPM(scanning probe microscope) tips with different radius of curvature were fabricated by a series of masking and etching processes. DLC(diamond-like carbon) and W-DLC (tungsten-incorporated diamond-like carbon) were coated on (100) silicon wafer by PACVD(plasma assisted chemical vapor deposition). Pull-off forces of Pure Si-wafer, DLC and W-DLC were measured with SPM(scanning probe microscope). Also, the same series of tests were carried out with the tips with different radius of curvature. Results showed that DLC and W-DLC showed much lower pull-off force than Si-wafer and Pull-off force increased with the tip radius.

• Tribology and Lubricants
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• v.16 no.3
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• pp.188-193
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• 2000

An experimental study was performed to discover the effect of environment on the tribological behavior of Si-incorporated diamond-like carbon(Si-DLC) film slid on a steel ball. The films were deposited on Si(100) wafers by a radio-frequency glow discharge of mixtures of benzene and dilute silane gases. Experiments using a ball-on-disk test-rig was performed in vacuum, dry air and ambient air conditions. It was observed that coefficient of friction decreased as the environment changed from vacuum, to dry air. Chemical analyses of debris suggested that low and stable friction is closely related to the formation of silicon-rich oxide debris and the rolling action.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.161-162
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• 2007

(1-102) R-면 사파이어 기판 위에 플라즈마 분자선 에피탁시 법으로 성장시킨 비극성 ZnO 박막의 표면 형상을 원자력간현미경(AFM) 및 투과전자현미경으로 분석하였다. AFM 관찰 결과 ZnO<0001> 방향으로 길쭉한 제방 모양의 표면 형상이 나타남을 알 수 있었고, 고분해능 투과전자현미경 관찰을 통해 박막 성장 중에 관찰되는 V(chevron 모양) 형상의 in-situ RHEED 패턴을 야기시키는 박막 표면의 facet 면을 원자 level에서 확인하였다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.106-111
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• 2003

Tantalum nitride(TaN) films were deposited by atomic layer deposition(ALD) and plasma assisted atomic layer deposition(PAALD). The deposition of the TaN thin film has been performed using pentakis (ethylmethlyamino) tantalum (PEMAT) and ammonia($NH_3$) as precursors at temperature of $250^{\circ}C$, where the temperature was proven to be ALD window for TaN deposition from our previous experiments. The PAALD deposited TaN film shows better physical properties than thermal ALD deposited TaN film, due to its higher density$(~11.59 g/\textrm{cm}^3$) and lower carbon(~ 3 atomic %) and oxygen(~ 4 atomic %) concentration of impurities.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.108-112
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• 2020

A certified reference material (CRM) for the analysis of nutrient elements in an edible mushroom (Ganoderma lyceum) powder has been developed (KRISS CRM 108-10-011). The mass fractions of calcium (Ca), iron (Fe), and zinc (Zn) were measured by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). To dissolve the fungi cell wall of mushroom consisted of chitin fibers, sample preparation method by single reaction chamber type microwave-assisted acid digestion with acid mixtures was optimized. The mean measurement results obtained from 12 sample bottles were used to assign as the certified values for the CRM and the between-bottle homogeneities were evaluated from the relative standard deviations. The certified values were metrologically traceable to the definition of the kilogram in the International System of Units (SI). This CRM is expected to be used for validation of analytical methods or quality control of measurement results in analytical laboratories when they determine the mass fractions of elements in mushroom or other similar samples.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.24-31
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• 2005

A plused laser ablation deposition(PLAD) technique has been used for producing fine particle as well as thin film at relatively low substrate temperatures. However, in order to manufacture and evaluate such materials in detail, motions of plume particles generated by laser ablation have to be understood and interactions between the particles by ablation and gas plasma have to be clarified. Therefore this paper was focused on the understanding of plume motion in laser ablation assisted by hi plasmas at 100[mTorr]. One-dimensional hybrid model consisting of fluid and particle models was developed and three kinds of plume particles which are carbon atom(C), $ion(C^+)$ and electron were considered in the calculation of particle method. It was obtained that ablated $C^+$ was electrically captured in Ar plasmas by strong electric field(E). The difference between motions of the ablated electrons and $C^+$ made E strong and the collisional processes active. The energies of plume particles were investigated on a substrate surface. In addition the plume motion in Ar gas was also calculated and discussed.

• Journal of Embryo Transfer
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• v.25 no.2
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• pp.97-101
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• 2010

Intracytoplasmic sperm injection (ICSI) is one of the artificial fertilization methods when only a few sperm are available for insemination, and an important tool for the preservation of genetic materials of endangered animal species, especially the male is infertile. Different from other species such as mice and pigs, the conventional ICSI method which uses spiked pipette for injection (Spike-ICSI) is exhibited low success rates in cattle because the bovinesperm head membrane is hard to break during injection procedure. We chose piezo-assisted ICSI (Piezo-ICSI) for the improvement of the injection procedure including sperm head membrane rupture and efficient puncture of the plasma membrane of the oocytes. In this experiment, we compared the efficacy of the bovine ICSI embryo production between the Piezo-ICSI and Spike-ICSI. The second polar body extrusion, pronuclear formation, cleavage and blastocyst formation were evaluated after implementation of two different ICSI techniques. The Piezo-ICSI tended to show comparably higher rates of the second polar body extrusion (41.7%), the pronuclei formation (42.9%) and the two-cell cleavage (41.4%) than Spike-ICSI does (33.3%, 28.6% and 23.5%, respectively) although there is no statistic significance between two groups. In addition, the blastocysts were only obtained from the Piezo-ICSI group (10.3%). Our finding shows that the Piezo-ICSI may be used as an artificial fertilization method in cattle when in vitro fertilization is not applicable.