• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.275-278
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• 1999

We have grown vertically aligned carbon nanotubes in a large area of Co-Ni codeposited Si substrates by the thermal CVD using $C_2$H$_2$gas. Since the discovery of carbon nanotubes, Synthesis of carbon nanotubes for mass production has been achieved by several methods such as laser vaporization, arc discharge, and pyrolysis. In particular, growth of vertically aligned nanotubes is of technological importance for applications to FED. Recently, vertically aligned carbon nanotubes have been grown on glass by PECVD. Aligned carbon nanotubes can be also grown on mesoporous silica and Fe patterned porous silicon using CVD. Despite such breakthroughs in the growth, the growth mechanism of the alignment are still far from being clearly understood. Furthermore, FED has not been clearly demonstrated yet at a practical level. Here, we demonstrate that carbon nanotubes can be vertically aligned on catalyzed Si substrate when the domain density reaches a certain value. We suggest that steric hindrance between nanotubes at an initial stage of the growth forces nanotubes to align vertically and then nanotubes are further grown by the cap growth mechanism.

• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.95-100
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• 2018

The metal oxide/graphene nanocomposites are promising functional materials for high capacitive electrode material of secondary batteries, and high sensitive material of high performance gas sensors. In this study, vanadium dioxide($VO_2$) nanostructrures were grown on CVD graphene which was synthesized on Cu foil by thermal CVD, and exfoliated graphene which was exfoliated from highly oriented pyrolytic graphite(HOPG) using a vapor transport method. As results, $VO_2$ nanostructures on CVD graphene were grown preferential growth on abundant functional groups of graphene grain boundaries. The functional groups are served to nucleation site of $VO_2$ nanostructures. On the other hand, 2D & 3D $VO_2$ nanostructures were grown on exfoliated graphene due to uniformly distributed functional groups on exfoliated graphene surface. The characteristics of morphology controlled growth of $VO_2$/graphene nanocomposites would be applied to fabrication process for high capacitive electrode materials of secondary batteries, and high sensitive materials of gas sensors.

• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.41-46
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• 2016

In this study, gas flow and temperature distribution in the multi-wafer planetary CVD reactor for the Si epitaxial growth were analyzed. Although the structure of the reactor was simplified as the first step of the study, the three-dimensional analysis was performed taking all these considerations of the revolution of the susceptor and the rotation of satellites into account. From the analyses, a reasonable velocity field and temperature field were obtained. However, it was found that analyses including the upper structure of the reactor were required in order to obtain more realistic temperature results. DCS mole fraction above the satellite surface and the susceptor surface without satellite was compared in order to check the gas species mixing. We found that satellite rotation helped gases to mix in the reactor.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.262-267
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• 2015

We demonstrate the growth of single-walled carbon nanotubes (SWNTs) using ethylene-based chemical vapor deposition (CVD) and ferritin-induced catalytic particles toward growth temperature reduction. We first optimized the gas composition of $H_2$ and $C_2H_4$ at 500 and 30 sccm, respectively. On a planar $SiO_2$ substrate, high density SWNTs were grown at a minimum temperature of $760^{\circ}C$. In the case of growth using nanoporous templates, many suspended SWNTs were also observed from the samples grown at $760^{\circ}C$; low values of $I_D/I_G$ in the Raman spectra were also obtained. This means that the temperature of $760^{\circ}C$ is sufficient for SWNT growth in ethylene-based CVD and that ethylene is more effective that methane for low temperature growth. Our results provide a recipe for low temperature growth of SWNT; such growth is crucial for SWNT-based applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.418-419
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• 2007

Effects of Fe catalyst film and carbon nanotube (CNT) growth temperature on the characteristics of carbon nanotube were investigated in thermal chemical vapor deposition (CVD) process. Fe catalyst was prepared by DC magnetron sputter with thickness of 5-40 nm and pre-treated with ammonia gas. CNTs were grown at $700-900^{\circ}C$. It was found that the island formation of catalyst is necessary for the CNT growth. The diameter of these CNTs shows a strong correlation with the catalyst film thickness and growth temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.674-677
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• 2002

Vertically aligned CNTs were grown on Fe-deposited $SiO_2$ substrates using thermal CVD of acetylene gas. The size of Fe particle is controlled by the flow rate of $NH_3$ and pretreatment time, which leads to control the diameter of CNTs. As the diameter of CNTs decreases, the growth rate is enhanced with an inverse dependence of the CNT diameter. The growth rate of CNTs increases linearly as the growth time increases until 30 min but is rapidly decreased over 40 min. We found an inverse relation between the diameter and growth rate of carbon nanotubes. As the diameter of CNTs increases, the compartment layers of bamboo-shaped CNTs appear more frequently. A base-growth model is suitable to explain the dependence of growth rate and structure of CNTs on the diameter size of catalytic particles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.130-132
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• 2006

In this paper, the author describes a-C films grown in pure methane plasma without any diluent gas by using RF plasma-enhanced CVD, and the variations in their structural features and surface morphologies are examined as a function of substrate temperature. Raman spectroscopy and scanning electron microscopy were performed to characterize the properties of the film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.131-134
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• 2001

Vertically aligned carbon nanotubes are grown on iron-deposited silicon oxide substrates by thermal chemical vapor deposition of acetylene gas at the temperature range 750∼950$^{\circ}C$. As the growth temperature increases from 750 to 950$^{\circ}C$, the growth rate increases by 4 times and the average diameter also increases from 30 nm to 130 nm while the density increases progresively with the growth temperature and a higher degree of crystalline perfection can be achieved at 950$^{\circ}C$. This result demonstrates that the growth rate, diameter, density, and crystallinity of carbon nanotubes can be controlled with the growth temperature.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.4
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• pp.135-140
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• 2005

Thermal-fluid analysis was performed to understand the thermal behavior in the horizontal CVD reactor thereby to design a susceptor which has a uniform deposition rate during silicon EPI growing. Four different types of susceptor designs, standard (no hole susceptor), hole $\sharp$1 (240 mm), hole $\sharp$2 (150 mm) and hole $\sharp$3 (60 mm), were simulated by CFD (Computational Fluid Dynamics) tool. Temperature, gas flow, deposition rate and growth rate were calculated and analyzed. The degree of flatness of EPI wafer loaded on the susceptor was computed in terms of silicon growth rate. The simulation results show that the temperature and thermal distribution in the wafer are greatly dependent on inner diameter of hole susceptor and demonstrate that the introduction of hole in the susceptor can degrade wafer flatness. Maximum temperature difference appeared around holes. As the diameter of the hole decreases, flatness of the wafer becomes poor. Among the threes types of susceptors with the hole, optimal design which resulted a good uniform flatness ($5\%$) was obtained when using hole $\sharp$1.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.39-42
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• 1999

Nitrogen-doped SiC(3C) (N-SiC(3C)) epliayers were grown on Si(111) substrate at $1250^{\circ}C$ using chemical vapor deposition (CVD) technique by pyrolyzing tetramethylsilane(TMS) in $H_{2}$ carrier gas. SiC(3C) layer was doped using $NH_{3}$ during the CVD growth to be n-type conduction. Physical properties of N-SiC(3C) were investigated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) patterns, Raman spectroscopy, cross-sectional transmission electron microscopy (XTEM), Hall measurement, and current-voltage(I-V) characteristcs of the N-SiC(3C)/Si(p) diode. N-SiC(3C) layers exhibited n-type conductivity. The n-type doping of SiC(3C) could be controlled by nitrogen dopant using $NH_{3}$ at low temperature.