• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.165-170
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• 2005

There is an increasing interest in developing novel coating to improve the blood compatibility of medical implants. Diamond-like carbon(DLC) and titanium nitride(TiN) films have been proposed as potential biomedical coatings due to their chemical k physical properties and moderate biocompatibility. To study the correlation between blood compatibility and physical properties of the films, the fibrinogen adsorption on the surface as well as morphology & wettability were investigated. The quantity of fibrinogen adsorption are Tower for TiN than DLC, which correlates with a higher hydrophilicity of TiN film. To reduce the quantity of fibrinogen adsorption on the film, plasma treatment and furnace annealing were performed, respectively. With the use of oxygen plasma and furnace annealing, the amount of fibrinogen adsorption on TiN film was remarkably reduced, while there was no decrease of the quantity with DLC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.17-18
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• 2007

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.8
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• pp.701-706
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• 2006

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 post annealing temperature on the structural variation of the DLC films. The films were annealed at temperatures ranging from 300 to $900^{\circ}C$ in steps of $200^{\circ}C$ using RTA equipment in nitrogen ambient. The thickness of the film and interface between film and substrate were observed by surface profiler, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), respectively. Raman and X-ray photoelectron spectroscopy (XPS) analysis showed that DLC films were graphitized ($I_D/I_G$, G-peak position and $sp^2/sp^3$ increased) ratio at higher annealing temperature. The variation of surface as a function of annealing treatment was verified by a AFM and contact angle method.

• 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.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.101-105
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• 2019

ZnS substrates with excellent transmittance in the mid-infrared region ($3-5{\mu}m$) were prepared using hot pressing instead of conventional chemical vapor deposition (CVD). Diamond-like carbon(DLC) was coated on either one or both sides of the ZnS substrates to improve their mechanical properties and transmittance. More specifically DLC was coated using CVD with an Ar and $C_2H_2$ mixed gas, and Ge was used as the bonding layer. During CVD, the bias voltage was fixed to 500 V and analyzed by Fourier transform infrared spectroscopy (FT-IR), nanoindenter, scanning electron microscope and energy dispersive spectrometry. Results of hardness analysis using the nanoindenter, showed that DLC coating increased from 5.9 to 17.7 GPa after deposition. The FT-IR spectroscopy results showed that, in the mid-infrared region ($3-5{\mu}m$), the average transmittance of the samples with DLC coating on one and both sides increased by approximately 6% and approximately 11.2% respectively. In conclusion, the DLC coating improved the durability and transmittance of the ZnS substrates.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.362-366
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• 2007

In this research, the optimal grinding condition has been obtained by design of experiment (DOE) fur the development of aspheric lens for the 3 Mega Pixel, 2.5x optical zoom camera-phone module. Also, the tungsten carbide (WC) mold was processed by the method of ultra precision grinding under this optimal grinding condition. The influence of diamond-liked carbon (DLC) coating on form accuracy (PV) and surface roughness (Ra) of the mold was evaluated through measurements after DCL coating using ion plating on the ground mold. Also, aspheric glass lenses were molded, some before DLC coating of the mold and some after the DLC coating. The optical characteristics of each sample, molded by the different molds, were compared with each other.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.167-170
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• 2005

The two-dimensional (2D) and three-dimensional (3D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography (UV-NIL) were fabricated using two kinds of methods, which were a DLC coating process followed by the focused ion beam (FIB) lithography and the two-photon polymerization (TPP) patterning followed by nano-scale thick DLC coating. We fabricated 70 nm deep lines with a width of 100 nm and 70 nm deep lines with a width of 150 nm on 100 nm thick DLC layers coated on quartz substrates using the FIB lithography. 200 nm wide lines, 3D rings with a diameter of $1.35\;{\mu}m$ and a height of $1.97\;{\mu}m$, and a 3D cone with a bottom diameter of $2.88\;{\mu}m$ and a height of $1.97\;{\mu}m$ were successfully fabricated using the TPP patterning and DLC coating process. The wafers were successfully printed on an UV-NIL using the DLC stamp. We could see the excellent correlation between the dimensions of features of stamp and the corresponding imprinted features.

• Journal of the Korean institute of surface engineering
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• v.48 no.3
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• pp.87-92
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• 2015

Carbon thin films were deposited on STS 316L sheets by inductively coupled plasma enhanced magnetron sputtering with or without substrate bias voltage. Typical Raman spectrum for amorphous diamond-like carbon (DLC) was obtained, and the interfacial contact resistance (ICR) was measured to show its conductive nature. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion mechanism of the carbon coating under the polymer electrolyte membrane fuel cell (PEMFC) condition. According to the pore-corrosion mechanism, the electrolyte penetrates the carbon coating through the pores and reacts with the substrate. As the substrate corrosion proceeds, the pore enlargement occurs and the surface area of the substrate exposed to the electrolyte. Applicability of the carbon coating for the PEMFC bipolar plate was evaluated by potentiodynamic polarization experiments. Finally, an adhesion problem was briefly considered.

• Korean Journal of Materials Research
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• v.22 no.10
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• pp.552-561
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• 2012

Diamond-like carbon (DLC) films have been widely used in many industrial applications because of their outstanding mechanical and chemical properties like hardness, wear resistance, lubricous property, chemical stability, and uniformity of deposition. Also, DLC films coated on paper, polymer, and metal substrates have been extensively used. In this work, in order to improve the printing quality and plate wear of polymer printing plates, different deposition conditions were used for depositing DLC on the polymer printing plates using the Pulsed DC PECVD method. The deposition temperature of the DLC films was under $100^{\circ}C$, in order to prevent the deformation of the polymer plates. The properties of each DLC coating on the polymer concave printing plate were analyzed by measuring properties such as the roughness, surface morphology, chemical bonding, hardness, plate wear resistance, contact angle, and printing quality of DLC films. From the results of the analysis of the properties of each of the different DLC deposition conditions, the deposition conditions of DLC + F and DLC + Si + F were found to have been successful at improving the printing quality and plate wear of polymer printing plates because the properties were improved compared to those of polymer concave printing plates.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.124-129
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• 2023

This study assessed the influences of fluorine introduced into DLC films on the structural and mechanical properties of the sample. In addition, the effects of the fluorine incorporation on the compressive stress in DLC films were investigated. For this purpose, fluorinated diamond-like carbon (F-DLC) films were deposited on cobalt-chromium-molybdenum substrates using radio-frequency plasma-enhanced chemical vapor. The coatings were examined by Raman scattering (RS), Attenuated total reflectance Fourier transform infrared spectroscopic analysis (ATR-FTIR), and a combination of elastic recoil detection analysis and Rutherford backscattering (ERDA-RBS). Nano-indentation tests were performed to measure hardness. Also, the residual stress of the films was calculated by the Stony equation. The ATR-FTIR analysis revealed that F was present in the amorphous matrix mainly as C-F and C-F₂ groups. Based on Raman spectroscopy results, it was determined that F made the DLC films more graphitic. Additionally, it was shown that adding F into the DLC coating resulted in weaker mechanical properties and the F-DLC coating exhibited lower stress than DLC films. These effects were attributed to the replacement of strong C = C by feebler C-F bonds in the F-DLC films. F-doping decreased the hardness of the DLC from 11.5 to 8.8 GPa. In addition, with F addition, the compressive stress of the DLC sample decreased from 1 to 0.7 GPa.