• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.6
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• pp.311-316
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• 2002

Two different approaches, namely two-step deposition process and Bias-Enhanced Nucleation (BEN) technique have been examined for deposition of high quality diamond thin film on polycrystalline Ni which has low chemical activity with the carbon neutrals provided from the $CH_4/H_2$mixtures. A two-step deposition process, consisted of pre-deposition of soot layer at lower temperatures and subsequent deposition at higher temperature condition, has been developed to deposit diamond layer directly on Ni substrate. Diamond particles were observed after deposition step at $925^{\circ}C$ for 5 hours and those particles seem to be nucleated from the soot layer pre-deposited at lower temperatures ($810^{\circ}C$). Diamond particles of a substantial size were found on Ni substrate after biasing -220 V for 10 minutes and subsequent deposition for 2 hours while no diamond particles were observed under the conditions without applied bias.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.593-600
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• 2000

This paper investigated the conduction path and conduction mechanism in undoped polycrystalline diamond thin films deposited by microwave chemical vapor deposition. The resistances measured by ac impedance spectroscopy with different directions can not be explained by the previously-known surface conduction model. The electrodeposition of Cu and electroetching of Ag experiments showed that the conduction path is the grain boundaries within the diamond films. The electodeposition of Cu with an insulating surface layer further proved that the main conduction path in polycrystalline films in the grain boundaries. The film with high electrical conductivity has low activation energy of 45meV and higher dangling bond density. By considering the results and surface C chemical bonds, the H-C-C-H bonds at surface and in grain boundaries might be the origin of high conductivity in undoped diamond films.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.28-32
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• 2010

Technical demands for aspheric glass lens formed in market increases its application from simple camera lens module to fiber optics connection module in optical engineering. WC is often used as a metal core of the aspheric glass lens, but the long life time is issued because it fabricated in high temperature and high pressure environment. High hard thin film coating of lens core increases the core life time critically. Diamond Like Carbon(DLC) thin film coating shows very high hardness and low surface roughness, i.e. low friction between a glass lens and a metal core, and thus draw interests from an optical manufacturing industry. In addition, DLC thin film coating can removed by etching process and deposit the film again, which makes the core renewable. In this study, DLC films were deposited on the SiC ceramic core. The process variable in FVA(Filtered Vacuum Arc) method was the substrate bias-voltage. Deposited thin film was evaluated by raman spectroscopy, AFM and nano indenter and measured its crystal structure, surface roughness, and hardness. After applying optimum thin film condition, the life time and crystal structure transition of DLC thin film was monitored.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1699-1701
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• 1999

We prepared diamond thin films on WC-Co substrate in $H_2-CH_4-O_2$ gas mixture using 13.56MHz RF PACVD. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy were used to analyze the nature of thin film. and Rockwell test to analyze the adhesion between thin film and substrate. The good diamond quality and adhesion was appeared with cemented tungsten carbide substrate treated with oxygen plasma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1010-1013
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• 2006

Hydrogenated Diamond-like carbon (DLC) films were Prepared by the radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method on silicon substrates using methane $(CH_4)$ and hydrogen $(H_2)$ gas for the application to solid lubricant of MEMS devices. We have checked the influence of varying RF power on tribological properties of DLC film. We have checked their performance as two kinds of method such as FFM (Friction Force Microscope) and BOD (Ball-on Disk) measurement. The friction coefficients and the contact number of cycles to steady state decreased as the increase of RF power with FFM and BOD measurement, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.398-401
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• 1999

We prepared diamond thin films on WC-Co substrate in a mixtured $H_2-CH_4-O_2$, gas, using 13.%MHz RF PACVD. Scanning electron microscopy, X-ray diffraction and Rarnan spectroscopy were used to analyze the characteristics of thin film, and tribometer of ball-on-disk type were used to test the wear resistance between thin film and substrate. The good diamond quality and wear resistance was appeared with cemented tungsten carbide substrate treated with oxygen plasma.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.457-463
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• 1994

The growth condition of highly oriented textured diamond film on a (100) Si substrate was investigated as a function of texture orientation. The growth process consisted of biased enhanced nucleation (BEN) and texture growth. The substrate was under the plasma of 6% CH4-94% H2 with negative bias of 200V during the BEN which grounded during the texture growth. The texture orintation changed from <100> to <110> by increasing substrate temperature. The nearly perfect match between textured diamond grains and the Si substrate could be obtained under the condition of <100> texture. The degree of tilt mismatch increased with the increase of deviation of texture orientation from <100>. The degree of twist mismatch appeared to increase abruptly beyond the critical deviation of texture orientation from <100> because the nuclei having the same orientation as the substrate were no more preferred grains for texture formation.

• 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.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.25-31
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• 2019

In this study, a new adhesion evaluating equipment and data processing methods were developed to overcome some limitations of existing evaluating equipment. Nano-diamond coated tool is a specimen of experiment. When applying frictional force and shear force on the specimen by a rotating polishing pad, delamination occurs at a moment. During each experiment, the vibration, load, and torque is obtained by accelerometer, loadcell and torque s+ kpensor. Frictional force and coefficient of friction are obtained by calculating torque and load. Based on FFT transformation, acceleration is processed and analyzed. As a result, the moment of delamination and the load at that time can be detected by the new developed equipment and measurement system. Finally, we call this load as an Adhesion force.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.06a
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• pp.173-173
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• 1998