• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.295.1-295
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• 2001

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.539-549
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• 1989

Polycrystalline TiO2 thin films were deposited on Si and Al2O3 substrates by CVD method. Ethyl titanate, Ti(OC2H5)4, was used as a source material for Ti and O, and Ar was used for carrier gas. In the surface chemical reaction controlled deposition condition, the apparent activation energy of 6.74 Kcal/mole was obtained, and the atomic adsorption on substrate surface was proved to be governed by Rideal-Elley mechanism. In the mass transfer controlled deposition condition, the deposition rate was in a good agreement with the result which was calculated by the simple boundary layer theory. It was also observed that TiO2 thin films show different surface morphology according to the different deposition mechanism, which was fixed by deposition conditions. This phenomenon could be well explained by the surface perturbation theory.

• Corrosion Science and Technology
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• v.13 no.2
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• pp.56-61
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• 2014

The purpose of this work is to investigate the effect of dissolved hydrogen concentration on crud deposition onto the fuel cladding surface in the simulated primary environments of a pressurized water reactor. Crud deposition tests were conducted in the dissolved hydrogen concentration range of 5~70 cc/kg at $325^{\circ}C$ for 14 days. Needle-shaped NiO deposits were formed in the hydrogen range of 5~25 cc/kg, while polygonal nickel ferrite deposits were observed at a hydrogen concentration above 35 cc/kg. However, the dissolved hydrogen content seems to have little effect on the amount of crud deposits.

• Progress in Superconductivity
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• v.7 no.1
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• pp.69-76
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• 2005

Complex single buffer composed of yttrium and samarium oxide was deposited on the metallic substrates by MOCVD (metal organic chemical vapor deposition) method using single liquid source. Two different types of the substrates with in-plane textures of about $8{\sim}10$ degree of Ni and $3at.\%W-Ni$ alloy were used. Y(tmhd: 2,2,6,6-tetramethyl-3,5-heptane dionate)$_3$:Sm(tmhd)$_3$ of liquid source was adjusted to 0.4:0.6 to minimize the lattice mismatch between the complex single buffer and the YBCO. The epitaxial growth of $(Y_{x}Sm_{1-x})_{2}O_3$ was achieved at the temperature higher than $500^{\circ}C$ in $O_2$ atmosphere. However, it was found that the formation of NiO accelerated with increasing deposition temperature. By supplying $H_{2}O$ vapor, this oxidation of the substrate could be suppressed throughout the deposition temperatures. We could get the epitaxial growth on pure Ni substrate without the formation of NiO. The competitive (222) and (400) growths were observed at the deposition temperatures of $650\~750^{\circ}C$, but the (400) growth became dominant above $800^{\circ}C$. The $(Y_{x}Sm_{1-x})_{2}O_3$-buffered metallic substrates can be used as the buffer for YBCO coated conductor.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.222-222
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• 2011

Titanium dioxide (TiO2) has a number of applications in optics and electronics due to its superior properties, such as physical and chemical stability, high refractive index, good transmission in vis and NIR regions, and high dielectric constant. Atomic layer deposition (ALD), also called atomic layer epitaxy, can be regarded as a special modification of the chemical vapor deposition method. ALD is a pulsed method in which the reactant vapors are alternately supplied onto the substrate. During each pulse, the precursors chemisorb or react with the surface groups. When the process conditions are suitably chosen, the film growth proceeds by alternate saturative surface reactions and is thus self-limiting. This makes it possible to cover even complex shaped objects with a uniform film. It is also possible to control the film thickness accurately simply by controlling the number of pulsing cycles repeated. We have investigated the ALD of TiO2 at 100$^{\circ}C$ using precursors titanium tetra-isopropoxide (TTIP) and H2O on -O, -OH terminated Si surface by in situ X-ray photoemission spectroscopy. ALD reactions with TTIP were performed on the H2O-dosed Si substrate at 100$^{\circ}C$, where one cycle was completed. The number of ALD cycles was increased by repeated deposition of H2O and TTIP at 100$^{\circ}C$. After precursor exposure, the samples were transferred under vacuum from the reaction chamber to the UHV chamber at room temperature for in situ XPS analysis. The XPS instrument included a hemispherical analyzer (ALPHA 110) and a monochromatic X-ray source generated by exciting Al K${\alpha}$ radiation (h${\nu}$=1486.6 eV).

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.339.1-339.1
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• 2014

In this paper we studied the application of inter-poly dielectric as silicon dioxide-like film was deposited by the higher energy assisting deposition (HEAD) process the modified CCP process, which enables low temperature (LT) process and improving film density. In these experiments the relative hydrogen concentration of $SiO_2$-like films deposited on silicon substrate were analyzed by the secondary ion mass spectroscopy (SIMS) and it was shown that our lower hydrogenated oxide (LHO) film prepared by HEAD process with the precursor contained the siloxane species had lower hydrogen concentration, $8{\times}10{\cdot}^{22}cm{\cdot}^3$ than that of the commercial undoped silicon glass (USG) film ($1{\times}10{\cdot}^{21}cm{\cdot}^3$) prepared by the high density plasma-chemical vapor deposition (HDP-CVD). We consider that the LHO film deposited by HEAD process used as high performance material into Flash memory devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1025-1027
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• 2009

Novel low temperature deposition process for nano-crystalline Si thin film is developed with the hyper-thermal neutral beam (HNB) technology. By our HNB assisted CVD system, the reactive particles can induce crystalline phase in Si thin films and effectively combine with heating effect on substrate. At low deposition temperature under $80^{\circ}C$, the HNB with proper incident energy controlled by the reflector bias can effectively enhance the nano-crystalline formation in Si thin film without any additional process. The electrical properties of Si thin films can be varied from a-Si to nc-Si according to change of HNB energy and substrate temperature. Characterization of these thin films with conductivity reveal that crystalline of Si thin film can increase by assist of HNB with appropriate energy during low temperature deposition. And low temperature prcoessed nc-Si TFT performance has on-off ratio as order 5.

• Journal of Powder Materials
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• v.14 no.4
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• pp.238-244
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• 2007

The electrophoretic deposition process of Ni nano-particles in organic suspension was employed for self-repairing of heat exchanger tubes. For this purpose, Ni nano-particles prepared by levitational gas condensation method were dispersed into the solution of ethanol with the addition of dispersant Hypermer KD2. For electrophoretic deposition of Ni nano-particles on the Ni alloy specimen, constant electric fields of 20 and 100 V $cm^{-1}$ were applied to the specimen in Ni-dispersed solution. It was found that as electrophoretic deposition proceeds, the size of the pit or crack remarkably decreased due to the agglomeration of Ni nano-particles at the pit or crack. This strongly suggests that the electrophoretic mobility of the charged particles is larger for the damaged part with a higher current value rather than outer surfaces with a lower current value.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.615-619
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• 2007

MgO layer plays an important role for plasma display panels (PDPs). In this experiment, ion beam assisted deposition (IBAD) methode was uesed to deposit a MgO thin film and the assisting oxygen ion beam energy was varied from 100 eV to 500 eV. In order to investigate the relationship between the secondary electron emission and the defect levels of the MgO layer, we measured the cathodoluminescence (CL) spectra of the MgO thin films, and we analyzed the CL peak intensity and peak transition. The results showed that the assisting ion beam energy played an important role in the peak intensity and the peak transition of the CL spectrum. The properties of MgO thin film were also analyzed using XRD and SEM, these results showed the assisting ion beam energy had direct effect on characteristics of MgO thin film.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.131-136
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• 2018

Background: We investigated the current characteristics of a thin-film Ag electrode on a chemical vapor deposition (CVD) diamond. The CVD diamond is widely recognized as a radiation detection material because of its high tolerance against high radiation, stable response to various dose rates, and good sensitivity. Additionally, thin-film Ag has been widely used as an electrode with high electrical conductivity. Materials and Methods: Considering these properties, the thin-film Ag electrode was deposited onto CVD diamonds with varied deposition thicknesses (${\fallingdotseq}50/98/152/257nm$); subsequently, the surface thickness, surface roughness, leakage current, and photo-current were characterized. Results and Discussion: The leakage current was found to be very low, and the photo-current output signal was observed as stable for a deposited film thickness of 98 nm; at this thickness, a uniform and constant surface roughness of the deposited thin-film Ag electrode were obtained. Conclusion: We found that a CVD diamond radiation detector with a thin-film Ag electrode deposition thickness close to 100 nm exhibited minimal leakage current and yielded a highly stable output signal.