• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.24-28
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• 1997

Diamond deposition by muti-cathode DC PACVD has been investigated. Five cathodes were independently connected to their own DC power supplies. The voltage and current of each cathods were varied up to 700 V and 3.5 A, respectively. The plasma formation and the diamond deposition behaviour on a substrate of 3 inch in diameter were investigated by optical emission spectroscopy, SEM and Raman spectroscopy. The plasma formed by five cathodes was non-uniform, which was depended on the geometry of cathods array. The growth rate and the quality of diamond film were closely related to the spatial distribution of the plasma.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.373-376
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• 1997

Diamond thin films were deposited on P-type(100) Si wafers using MPECVD. Prior to deposition, mechanical scretching was done to improve density of nucleation sites with diamond paste of 0.25${\mu}{\textrm}{m}$ size. Diamond films were deposited under the following conditions : methane concentration of 0.5~5%, oxygen concentration of 0~70%, process pressure of 70Torr, process temperature of 900~95$0^{\circ}C$, and deposition time 5hrs. The changes of the morphology and the growth rates of the deposits with the experimental conditions are expriend by Scanning Electron Microscopy. Raman Spectroscopy and X-ray Diffraction method.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.37-37
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• 2002

Diamoncl/Mo/Ni multi-layers on SKH-51 steel substrate was prepared to improve the abrasive wear resistance of a tool and die by a commercial chemical vapor deposition unit and electro-plating. The diamond after 7 hour deposition had cuba-octahedral structure with 2~5$\mu\textrm{m}$ grains. The existence of non-ferrous metals such as chromium, nickel and molybdenum between diamond and SKH-51 substrate results in forming higher quality of diamond layer by retarding carbon diffusion in the diamond layer during deposition, and also improving hardness and wear resistance. Surface cracks on the film was sometimes observed by the difference of by the thermal expansion coefficients between the steel substrate and the deposited layers during cooling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.563-572
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• 1998

An experimental study of hot filament chemical vapor deposition(HFCVD) has been carried out for the fabrication of diamond thin film. Of particular interest is the measurement of deposition uniformity on large substrates. Experimental apparatus including a vacuum chamber, heating elements, etc. has been designed and manufactured. Deposition profiles for different pretreatment powders and different flow rates have been measured in conjunction with the measurement of substrate temperature distribution on a large substrate surface. As the flow rate increases, deposition rate increases, however, the crystallinity becomes worse. Higher growth rate has been found on the region closer to the center location where substrate temperature is higher. The crystallinity has been improved as gas flow rate decreases. The growth rate and morphology of deposition were identified by SEM and the existence of diamond phase was proved by Raman spectroscopy.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.6
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• pp.403-409
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• 1999

We fabricated diamond like carbon (DLC) thin films using pulsed laser deposition (PLD) method. Among many deposition parameters, the effects of the deposition temperature and the laser energy density were investigated. Structural properties of the films were studied by Raman spectroscopy. The surface morphologies and cross-section imagies of the films were investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM) respctively. DLC thin films fabricated at $12 J/cm^2$ of a laser energy density and $300^{\circ}C$ of a deposition temperature showed the best quality.

• Transactions on Electrical and Electronic Materials
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• v.1 no.1
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• pp.1-5
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• 2000

Diamond films have been achieved on Si(100) substrates using helicon plasma chemical vapor deposition(HPCVD), Gas mixtures with methane and hydrogen have been used. The growth characteristics were investigated by means of X-ray photoelectroton spectroscopy, Atomic force microscopy and X-ray diffraction. We obtained a plasma density as high as 10$\^$10/~10$\^$11/ cm$\^$-3/ by helicon source. The smooth(100) faces of submicron diamond crystallites were found to exhibit pyramidal shaped architecture, The XPS spectrum for the nucleation layer indicates the presence of diamond at 285.4 eV, close to the reported value of 285.5 eV for diamond , XRD results demonstrates the existence of polycrystalline diamond as the diamond (111) and (220) peaks.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.45-50
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• 2004

Highly oriented diamond (HOD) films in polycrystalline can be grown on the (100) silicon substrate by microwave plasma CVD. Bias enhanced nucleation (BEN) method was adopted for highly oriented diamond deposition with high nucleation density and uniformity. The substrate was biased up to -250[Vdc] and bias time required for forming a diamond film was varied up to 25 minutes. Diamond was deposited by using $\textrm{CH}_4$/CO and $H_2$ mixture gases by microwave plasma CVD. Nucleation density and degree of orientation of the diamond films were studied by SEM. Thermal conductivity of the diamond films was ∼5.27[W/cm.K] measured by $3\omega$ method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.905-908
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• 2000

The growth properties of diamond grain were examined by Raman spectroscopy and microscope images. Diamond thin films were prepared on single crystal Si wafers by microwave Plasma chemical vapor deposition. Preparation conditions, substrate temperature, boron concentration and deposition time were controlled differently. Prepared diamond thin films have different surface morphology and grain size respectively Diamond grain size was gradually changed by substrate temperature. The biggest diamond grain size was observed in the substrate, which has highest temperature. The diamond grain size by boron concentration was slightly changed but morphology of diamond grain became amorphous according to increasing of boron concentration. Time was also needed to be a big diamond grain. However, time was not a main factor for being a big diamond grain. Raman spectra of diamond film, which was deposited at high substrate temperature, showed sharp peaks at 1334$cm^{-1}$ / and these were characteristics of crystalline diamond. A broad peak centered at 1550$cm^{-1}$ /, corresponding to non-diamond component (sp$^2$carbon), could be observed in the substrate, which has low temperature.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.949-951
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• 1992

A low pressure DC plasma jet has been used to obtain diamond films from a mixture of $CH_4$ and $H_2$ with high deposition rate (>1$\mu\textrm{m}$/min). The effects of the deposition conditions such as torch geometry, substrate temperature, gas mixing ratio, chamber pressure, axial magnetic field on the diamond film properties such as morphology, purity, uniformity of the film and deposition rate, etc. have been examined with the aid of Scanning Electron Microscopy, X-Ray Diffraction, and Raman Spectroscopy. Both the growth rate and particle size increased rapidly for low methane concentrations but saturated and the morphology changed from octahedral to cubic structure when the concentration exceeded 1.0 %. Higher growth rates (>1.5${\mu}m$/min) can be obtained by applying an axial magnetic field to the DC plasma jet. Diamond obtained from the magnetized plasma jet also shows a sharp peak at 1332.5$cm^{-1}$ in the Raman Spectra and this result implies that higher growth rate with a good quality diamond films can he obtained by applying an external magnetic field to the plasma jet.

• 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.