• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.194-194
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• 1999

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.356-356
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• 2010

Tribological behaviors of the hard film on soft substrate system were explored using the hard thin film of diamond-like carbon (DLC) coated the soft polymer of polydimethysiloxane (PDMS). A DLC film with the Young's modulus of 100 GPa was coated on PDMS substrate with Young's modulus of 10 MPa using plasma enhanced chemical vapor deposition (PECVD) technique. The deposition time was varied from 10 sec to 10 min, resulting in nanoscale roughness of wrinkle patterns with the thickness of 20 nm to 510 nm, respectively, at a bias voltage of $400\;V_b$, working pressure 10 mTorr. Nanoscale wrinkle patterns with 20-100 nm in width and 10-30 nm height were formed on DLC coating due to the residual stress in compression and difference in Young's modulus. Nanoscale roughness effect on tribological behaviors was observed by performing a tribo-experiment using the ball-on-disk type tribometer with a steel ball of 6 mm in diameter at the sliding speed of 220 rpm, normal load of 1N and 25% humidity at ambient temperature of $25^{\circ}C$. Friction force were measured with respect to thickness change of coated DLC thin film on PDMS. It was found that with increases the thickness of DLC coating on PDMS, the coefficient of friction decreased by comparison to that of the uncoated PDMS. The wear tracks before and after tribo-test were analyzed using SEM and AFM.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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• pp.76-81
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• 2014

The Engineering ceramics have some excellent properties as materials for modern mechanical and electrical components. It is, however, not easy to polish them efficiently because they are strong and hard. This study is carried out to obtain a mirror surface on engineering ceramics by surperfinishing with high efficiency. To achieve this, we conducted a series of polishing experiments using representative engineering ceramics, such as $Al_2O_3$, SiC, $Si_3N_4$ and $ZrO_2$, using diamond abrasive film from the perspective of oscillations peed, the rotational speed of the workpiece, contact roller hardness, contact pressure and feed rate. Furthermore, the polishing efficiency and characteristics for engineering ceramics are discussed on the basis of optimal polishing time and surface roughness. Our results confirmed that efficient superfinishing conditions and polishing characteristics of engineering ceramics can be determined.

• KSTLE International Journal
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• v.10 no.1_2
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• pp.1-5
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• 2009

This paper reports an investigation on nanotribological properties of silicon nanochannels coated by a diamond-like carbon (DLC) film. The nanochannels were fabricated on Si (100) wafers by using photolithography and reactive ion etching (RIE) techniques. The channeled surfaces (Si channels) were then further modified by coating thin DLC film. Water contact angle of the modified and unmodified Si surfaces was examined by an anglemeter using the sessile-drop method. Nanotribological properties, namely friction and adhesion forces, of the Si channels coated with DLC (DLC-coated Si channels) were investigated in comparison with those of the flat Si, DLC-coated flat Si (flat DLC), and Si channels, using an atomic force microscope (AFM). Results showed that the DLC-coated Si channels greatly increased hydrophobicity of silicon surfaces. The DLC coating and Si channels themselves individually reduced adhesion and friction forces of the flat Si. Further, the DLC-coated Si channels exhibited the lowest values of these forces, owing to the combined effect of reduced contact area through the channeling and low surface energy of the DLC. This combined modification could prove a promising method for tribological applications at small scales.

• Tribology and Lubricants
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• v.11 no.5
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• pp.59-65
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• 1995

Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum ($3 \times 10^{-5}$ Torr) using a ball (AISI 52100 steel)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor deposition method. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than that of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films were explained with the changes in chemical structures of the films. Result also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanisms and roles of the polymer-like wear debris were presented and discussed.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.325-329
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• 2003

Effects of thermal treatment on the structural properties of diamond-like carbon (DU) films were examined. The DLC films were deposited by using a modified filtered cathodic vacuum arc (FCVA) deposition system and by varying the negative substrate bias voltage, deposition time, and nitrogen flow rate. Thermal treatment on DLC films was performed using a rapid thermal annealing (RTA) process at $600^{\circ}C$ for 2min. Raman spectroscopy, x-ray photoemission spectroscopy (XPS), atomic force microscope (AFM), and surface profiler were used to characterize the I$_{D}$I$_{G}$ intensity ratio, sp$^3$ hybrid carbon fraction, internal stress, and surface roughness. It was found for all the deposited DLC films that the RTA-treatment results in the release of internal compressive stress, while at the same time it leds to the decrease of sp$^3$ fraction and the increase of I$_{D}$I$_{G}$ intensity ratio. It was also suggested that the thermal treatment effect on the structural property of DLC films strongly depends on the diamond-like nature (i.e., sp$^3$ fraction) of as-deposited film.ed film.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.247-247
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• 2010

DLC(diamond-like carbon)는 비정질 고상 탄소의 하나로 다이아몬드의 유사한 높은 경도, 내마모성, 윤활성, 전기절연성, 화학적 안정성을 가지고 있는 재료이다. 이러한 우수한 특성 때문에 DLC는 박막의 형태로 여러 종류의 보호코팅에 많이 응용되고 있다. DLC의 광범위한 응용에 있어 가장 큰 문제점은 박막이 갖는 높은 잔류응력과 이에 따른 기판과의 낮은 접착성으로 알려져 있다. 최근 연구에 의하면, plasma pre-treatment를 통해 PTFE기판에 DLC박막의 adhesion strength를 증진 시킬 수 있다고 보고하였다. 또한 ion beam technique를 이용하여 잔류응력을 줄이고 기판과의 접착력을 높일 수 있다는 것도 보고 되었다. 이에 기인하여 pre-treatment가 DLC합성에 잔류응력을 낮추고 기판과의 접착성을 높이는 효과를 보일 것이라고 가정하고 연구하였다. 본 연구에서 pre-treatment가 Diamond-like Carbon의 stainless steel 합성시 stress와 adhesion에 어떤 효과가 있는지 알아보기 위해, pre-treatment시와 synthesis of DLC film시에 13.56MHz 150W RF플라즈마 화학기상 증착 (RF-PECVD) 법을 통해 합성되었다. pre-treatment시에 H2(80 sccm), O2(10 sccm), N2(20 sccm)의 가스 종류를 다르게 하였고, synthesis of DLC film시에는 CH4 (20 sccm), H2 (80 sccm)가스의 유량을 고정하였다. 합성된 DLC 박막은 Contact Angle Analyze, Raman spectroscopy, Scratch tester를 이용하여 접촉각, D peak Position, G peak Position, ID/IG ratio, 접착력을 측정하였다.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.403-408
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• 2021

Various surface colors are predicted and implemented using the interference color generated by controlling the thickness of nano-level diamond like carbon (DLC) thin film. Samples having thicknesses of up to 385 nm and various interference colors are prepared using a single crystal silicon (100) substrate with changing processing times at low temperature by plasma-enhanced chemical vapor deposition. The thickness, surface roughness, color, phases, and anti-scratch performance under each condition are analyzed using a scanning electron microscope, colorimeter, micro-Raman device, and scratch tester. Coating with the same uniformity as the surface roughness of the substrate is possible over the entire experimental thickness range, and more than five different colors are implemented at this time. The color matched with the color predicted by the model, assuming only the reflection mode of the thin film. All the DLC thin films show constant D/G peak fraction without significant change, and have anti-scratch values of about 19 N. The results indicate the possibility that nano-level DLC thin films with various interference colors can be applied to exterior materials of actual mobile devices.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.356-360
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• 2001

Properties of a free-standing diamond wafer with a diameter of 80 mm and a thickness of 900~950 $mu extrm{m}$ deposited by the multi-cathode direct current plasma assisted chemical vapor deposition (MCDC PACVD) method were investigated. Defects of the diamond film were observed by optical transmission microscopy and its crystallinity was characterized by Raman and IR spectroscopy. Defects were distributed partially on boundaries of the grain. In the grain, (111) plane contained a higher defect density than that on (100) plane. FWHM of Raman diamond peak and IR transmission at 10.6 $\mu\textrm{m}$ were 4.6 $\textrm{cm}^{-1}$ /~5.3 $\textrm{cm}^{-1}$ and 51.7 ~ 61.9 %, and their uniformity was $\pm$7% and $\pm$9%, respectively. The diamond quality decreased with going from center to edge of the wafer.