• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1378-1379
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• 2006

Carbon nanotubes (CNTs) with few defects and very small amount of amorphous carbon coating have been synthesized by catalytic decomposition of acetylene in $H_2$ over well-dispersed metal particles supported on MgO. The yield, quality and diameters of CNTs were obtained by control of catalyst metal compositions to be used. The optimization condition of carbon nanotubes with high yield is when Co and Mo are in a 1:1 ratio and Fe metal contents to Co is increased on magnesium oxide support. It is also found that the diameter of the as-prepared CNTs can be controlled mainly by adjusting the molar ratio of Fe-Mo, Co-Fe, and Co-Mo versus the MgO support. Our results indicated that desired diameter distribution of CNTs is obtained by choosing or combining the catalyst to be employed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.164-165
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• 2007

The effect of hydrogen and oxygen plasma treatments on the structural properties of carbon nanotubes (CNTs) has been systematically investigated. The plasma treatment resulted in the removal of the amorphous carbon particles. As the plasma treatment time was longer, the CNT diameter was reduced, regardless of gas types. Especially, for the sample treated in hydrogen plasma, the catalyst metal on the tip of CNTs was eliminated.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.92.2-92.2
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• 2015

Negative-AND (NAND) flash의 대용량 및 소형화로 인해 10 nm급 공정을 도입한 128 Gb NAND flash가 개발된 이래, 공정이 미세화되면서 셀이 작이지고 간격이 좁아지게 되었다. 이로 인해 전자가 누설되는 간섭현상이 심화되게 된다. 이러한 문제를 해결하기 위해 기존 NAND의 평면 구조를 수직으로 적층하는 3D NAND 기술이 개발되었으며 차세대 소자를 위한 필수 기술로 각광받고 있다. 3D NAND에서 channel hole etching시 고 선택 비의 중요도가 증가하여 증착막 보호 역할을 하는 hardmask의 두께가 증가하게 되었으며 기존 하드마스크 대비 내식각성이 2배 이상 향상된 hard material 개발이 필요한 실정이다. 본 연구에서는 dopant에 따른 amorphous carbon layer (ACL)의 etch rate의 변화량을 Raman spectroscopy등의 측정장비를 이용하여 비교분석 하였다. dopant의 각각 유량별에 대한 etch rate 변화의 영향성을 비교하였다. dopant의 유량에 따라 etch rate이 변화하는 것을 관찰할 수 있었으며, 2000 sccm 이후에는 etch rate이 급격히 감소하는 경향을 보였다. Raman 측정결과, etch rate의 감소에 따라 G-peak의 red shift가 발생하였으며 두 peak 간의 차이 값이 etch rate의 변화율과 유사한 경향을 보이는 것을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.102-108
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• 2005

We have developed highly stabilized (p-i-n)-type protocrystalline silicon (pc-Si:H) multilayer solar cells. To achieve a high conversion efficiency, we applied a double-layer p-type amorphous silicon-carbon alloy $(p-a-Si_{1-x}C_x:H)$ structure to the pc-Si:H multilayer solar cells. The less pronounced initial short wavelength quantum efficiency variation as a function of bias voltage proves that the double $(p-a-Si_{1-x}C_x:H)$ layer structure successfully reduces recombination at the p/i interface. It was found that a natural hydrogen treatment involving an etch of the defective undiluted p-a-SiC:H window layer before the hydrogen-diluted p-a-SiC:H buffer layer deposition and an improvement of the order in the window layer. Thus, we achieved a highly stabilized efficiency of $9.0\%$ without any back reflector.

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.354-362
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• 2019

In order to apply thermoplastic composites using PETG resin to various industrial fields such as bicycle frames and industrial parts, it is necessary to verify the impact resistance, durability and mechanical properties of the manufactured composite materials. To improve the mechanical properties, durability and impact resistance of PETG resin, an amorphous resin, in this study, compound and injection molding process were carried out using various additives such as TiO2, carbon black, polyolefin elastomer, and PETG amorphous resin. The thermal and mechanical properties of the thermoplastic composites, and the Charpy impact strength. The analysis was performed to evaluate the characteristics according to the types of additives. DSC and DMA analyzes were performed for thermal properties, and tensile strength, flexural strength, and tensile strength change rate were measured using a universal testing machine to evaluate mechanical properties. Charpy impact strength test was conducted to analyze the impact characteristics, and the fracture section was analyzed after the impact strength test. In the case of POE material-added thermoplastic composites, thermal and mechanical properties tend to decrease, but workability and impact resistance tend to be superior to those of PETG materials.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.105-111
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• 1999

This paper presents experimental results on the electrical properties of hydrogenated amorphous carbon films(a-C:H) prepared by PECVD. DC conductance of a-C:H was measured as a function of temperatures in the range of 100 to 423K. We studied two a-C:H films: one was well explained by the Mott's Variable Range Hopping(VRH) rule, but the other sample did not follow it. However, the conduction data of second sample were well fitted to Shimakawa's Multi-Phonon Hopping(MPH) model according to which conductivity is proportional to $T^M$ with m=15-17. but, in our samples, m was 10-12. Also a-C:H showed several bias effects like relaxation of conductance, bias-dependent conductance and the change of conductance slope in 1n(${\sigma}{\sqrt{T}}$) vs. $T^{1/4}$ plot. In this study we interpret these data by bias-dependent detrapping model.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.84-91
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• 1997

Diamond film was deposited on Mo substrate at atmospheric pressure using a combustion flame apparatus with the addition of $H_2$. With the substrate temperature, the nucleation density of the substrate was increased. At temperatures above $1000^{\circ}C$, some of diamond was partly converted into graphite and etched by hydrogen atoms. With an increase of the $C_2H_2/O_2$ ratio, the nucleation density was increased. But crystals were cauliflower-shaped and a large number of amorphous carbon were deposited. With the addition of $H_2$, the nucleation density of diamond was increased by the improvement of surface activity. Diamond film of high crystallinity was deposited by etching amorphous carbon. With an increase of deposition time, the thickness of diamond film was increased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1332-1336
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• 2004

Amorphous carbon (a-C) films have been deposited on Si(100) substrate using RF magnetron system in order to investigate the electron field emission properties. The a-C films were treated by $N_2$ gas plasma at room temperature. Surface morphologices and structural properties of the a-C films before and after $N_2$ plasma treatment were observed by scanning electron microscopy and Raman spectroscope, respectively. Structural properties and surface morphology of the a-C films were changed by $N_2$ plasma treatment. The emission properties can be improved by the plasma treatment according to the contents of nitrogen on the a-C films which is varied by plasma treatment time. Before the plasma treatment, the a-C films are found to have a threshold field of 14 V/$\mu$m, but the a-C film treated by $N_2$ plasma for 30 min exhibit threshold field as low as 6.5 V/$\mu$m.

• Journal of Korean Vacuum Science & Technology
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• v.7 no.2
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• pp.33-38
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• 2003

Fluorinated amorphous carbon thin films (a-C:F) for the use of low dielectric constant intermetallic layer dielectrics are deposited by plasma enhanced chemical vapor deposition with $C_4$F$_{8}$ and Si$_2$H$_{6}$/He gas mixture as precursors. To characterize and improve film properties, we changed various conditions such as deposition temperature, and RF power, and we measured the thickness and refractive indexes and FT-IR spectrum before and after annealing. At low temperatures the film properties were very poor although the growth rate was very high. On the other hand, the growth rate was low at high temperature. The growth rate increased in accordance with the deposition pressure. The dielectric constants of samples were in the range of 1.5∼5.5∼5.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.284-284
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• 2011

Recently, the increasing degree of device integration in the fabrication of Si semiconductor devices, etching processes of nano-scale materials and high aspect-ratio (HAR) structures become more important. Due to this reason, etch selectivity control during etching of HAR contact holes and trenches is very important. In this study, The etch selectivity and etch rate of TEOS oxide layer using ACL (amorphous carbon layer) mask are investigated various process parameters in CH2F2/C4F8/O2/Ar plasma during etching TEOS oxide layer using ArF/BARC/SiOx/ACL multilevel resist (MLR) structures. The deformation and etch characteristics of TEOS oxide layer using ACL hard mask was investigated in a dual-frequency superimposed capacitively coupled plasma (DFS-CCP) etcher by different fHF/ fLF combinations by varying the CH2F2/ C4F8 gas flow ratio plasmas. The etch characteristics were measured by on scanning electron microscopy (SEM) And X-ray photoelectron spectroscopy (XPS) analyses and Fourier transform infrared spectroscopy (FT-IR). A process window for very high selective etching of TEOS oxide using ACL mask could be determined by controlling the process parameters and in turn degree of polymerization. Mechanisms for high etch selectivity will discussed in detail.