• Proceedings of the Korean Vacuum Society Conference
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• 1998.06a
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• pp.162-162
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• 1998

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.175-176
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• 2002

Our study is to search for tribological properties of diamond-like carbon (DLC) films as known as anti- wear hard thin film on various polymers. This report deals with the deposition of DLC films on various polymer substrates in vacuum by magnetron radio frequency (RF) sputtering method with using argon plasma and graphite, titanium target. The properties of friction and wear are measured using a ball-on-disk wear -testing machine. The properties of friction and wear have been remarkably improved by DLC coating. Moreover the composition of DLC films has been analyzed by using auger electron spectroscopy(AES). The wear rate of titanium-containing DLC film is lower than that of no-metal-containing DLC film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.431-431
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• 2007

In this paper, the LC alignment characteristics of the NDLC thin film deposited by PECVD and sputtering were reported respectively. The NDLC thin film deposited using sputter showed uniform LC alignment at the 1200 eV of the ion beam intensity and pretilt angle was about $2^{\circ}$ while the NDLC thin film deposited using the PECVD showed uniform LC alignment and high pretilt angle at the 1800 eV of the ion beam intensity. Concerning the ion beam intensity, uniform LC alignment of the NDLC thin film deposited by the sputtering was achieved at the lower intensity. And the pretilt angle of the NDLC thin film deposited by sputter was higher than those of NDLC thin film that was deposited using the PECVD. The uppermost of the thermal stability of NDLC thin film was $200^{\circ}C$, respectively. However, NDLC thin film deposited by the PECVD showed stability at high temperature without defects, compared to NDLC thin film deposited by the sputter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.973-976
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• 2008

In addition to its similarity to genuine diamond film, diamond-like carbon (DLC) film has many advantages, including its wide band gap and variable refractive index. In this study, DLC films were prepared by the RF PECVD (Plasma Enhanced Chemical Vapor Deposition) method on silicon substrates using methane ($CH_4$) and hydrogen ($H_2$) gas. We examined the effects of the RF power on the electrical properties of the DLC films. The films were deposited at several RF powers ranging from 50 to 175 W in steps of 25 W. The leakage current of DLC films increased at higher deposition RF power. And the resistivities of DLC films grown at 50 W and 175 W were $5\times10^{11}$ ${\Omega}cm$ and $2.68\times10^{10}$ ${\Omega}cm$, respectively.

• 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 Vacuum Society
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• v.9 no.2
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• pp.110-115
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• 2000

Deposition conditions of diamond thin films were optimized using hot-filament chemical vapor deposition (HFCVD). Boron-doped diamond thin films with varying boron densities were then fabricated using B4C solid pellets. Current-voltage responses and field emission currents were measured to test the characteristics of field emission display (FED). With the increase of boron doping, the crystal size of diamond decreased slightly, but its quality was not changed significantly in case of small doping. The I-V characterization was performed for Al/diamond/p-Si, and the current of doped diamond film was increased $10^4\sim10^5$ times as compared with that of undoped film. In the field emission properties, the electrons were emitted with low electric field with the increase of doping, while the emission current increased. The onset-field of electron emission was 15.5 V/$\mu\textrm{m}$ for 2 pellets, 13.6 V/$\mu\textrm{m}$ for 3 pellets and 11.1 V/$\mu\textrm{m}$ for 4 pellets. With the incorporation of boron, the slope of Fowler-Nordheim graph was decreased, revealing that the electron emission behavior was improved with the decrease of the effective barrier energy.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1772-1781
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• 2004

The mechanical as well as tribological characteristics of coating films as thin as a few nm become more crucial as applications in micro-systems grow. Especially, the amorphous carbon film has a potential to be used as a protective layer for micro-systems. In this work, quantitative evaluation of nano-indentation, scratching, and wear tests were performed on the 7nm thick amorphous carbon film using an Atomic Force Microscope (AFM). It was shown that AFM-based nano-indentation using a diamond coated tip can be feasibly utilized for mechanical characterization of ultra-thin films. Also, it was found that the critical load where the failure of the carbon film occurred was about 18${\mu}$N by the ramp load scratch test. Finally, the wear experimental results showed that the quantitative wear rate of the carbon film ranged 10$\^$-9/～10$\^$-8/ ㎣ /N cycle. These experimental methods can be effectively utilized for a better understanding the mechanical and tribological characteristics at the nano-scale.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.732-742
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• 1995

Effects of the substrate pretreatment on uncleation density of the diamond thin films have been investigated. The film was prepared using the hot-filament CVD reactor with the mixture of methane and hydrogen. The substrate pretreatment was done in three different ways: predeposition of carbon on the substrate, soot on the substrate, and graphite on the substrate. All three cases enhanced the nucleation density of diamond. And the effect was more marked in the first and the second cases than in the third one. In the first case where the substrate was predeposited by the carbon phase, a very smooth and uniform film of diamond could be obtained. Since the bound strength between the substrate and the predeposited carbon phase is relatively weak, separation of the diamond film layer from the substrate was found to be easy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.791-794
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• 2003

DLC thin films were prepared by microwave plasma-enhanced chemical vapor deposition method on silicon substrates using methane ($CH_4$) and hydrogen ($H_2$) gas mixture. The negative DC bias ($-450V{\sim}-550V$) was applied to enhance the adhesion between the film and the substrate. The films were characterized by Raman spectrometer. The surface morphology was observed by an atomic force microscope (AFM). And also, the friction coefficients were investigated by AFM in friction force microscope (FFM) mode, which were compared with the pin-on-disc (POD) measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.842-845
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• 2003

DLC thin films were prepared by microwave plasma-enhanced chemical vapor deposition method on silicon substrates using methane ($CH_4$) and hydrogen ($H_2$) gas mixture. The negative DC bias ($-450V{\sim}-550V$) was applied to enhance the adhesion between the film and the substrate. The films were characterized by Raman spectrometer. The surface morphology was observed by an atomic force microscope (AFM). And also, the friction coefficients were investigated by AFM in friction force microscope (FFM) mode, which were compared with the pin-on-disc (POD) measurement.