• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.170.2-170.2
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• 2016

DLC(Diamond like Carbon)는 Diamond와 유사한 물리화학적 특성을 보유한 막으로 고경도 및 우수한 내마모성, 화학적 안정성의 특성을 가지고 있다. DLC는 크게 카본의 막 형성 공정에서 카본 소스에 따라 수소가 포함된 DLC와 무수소DLC로 구분된다. Tetrahedral amorphous carbon (ta-C) 박막은 DLC 박막 중에서 가장 다이아몬드와 유사한 특성을 가지는 박막으로, a:C-H에 비해 높은 열적안정성, 경도(50~60 GPa) 및 내마모 특성이 우수하여, 현재 다양한 응용분야에 적용하고 있다. 본 연구에서는 무수소 DLC 형성을 위해 자장필터가 장착된 Filtered Vacuum Arc Source(FVAS)를 자체적으로 개발하여 연구를 진행하였다. FVAS 장비는 카본 이온 발생부와 Plasma Duct 부위, 전자석부위 구성되어 있으며, 본 연구에서는 Plasma Duct 부위의 Bias 제어를 통해 음극에서 기판으로 이동하는 카본이온의 에너지와 flux 변화를 통한 박막 증착 거동 및 물성 연구를 진행하였다. Plasma Duct Bias 변화는 각 0, 5, 10, 15, 20 V 조건으로 진행하였으며, 물성 평가는 경도(Hardness), 마찰계수, 응력(Stress), 전기전도 특성에 대한 분석을 진행하였다. 박막의 증착 거동에서는 Plasma Duct bias 변화에 따라10 V에서 가장 높은 증착 거동을 가지다 감소하는 경향을 확인 하였으며, 박막의 물성 특성 평가 시에도 이와 유사하게 특성의 차이를 관찰하였다. 이는 음극부위에서 형성된 카본이온이 기판에 도달 시에 Plasma Duct Bias 변화에 따라 이온의 Flux 및 에너지 변화로 인해 박막의 밀도 및 ta-C 막의 물성 변화로 예상되며, 이를 분석하기 위해 라만분석 및 기판 도달 에너지 분석을 진행하였다

• 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.

• Journal of the Korean institute of surface engineering
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• v.42 no.4
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• pp.173-178
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• 2009

DLC film was synthesized on plastic injection mold(SKD11, $30\;mm\;{\times}\;19\;mm\;{\times}\;0.5\;mm$) and Si(100) wafer for 2 h at $130^{\circ}C$ under 6 mTorr using hybrid method of rf sputtering and ion source. The obtained film was analysed by Raman spectroscopy, AFM, TEM, Nano indenter and scratch tester, etc. The film was defined as an amorphous phase. In the Raman spectrum, broad peak of $sp^2$-bonded carbon attributed to graphite at $1550\;cm^{-1}$ were observed, and the ratio of ID($sp^3$ diamond intensity)/IG($sp^2$ graphite intensity) was approximately 0.54. The adhesion of DLC film was more than 80 N with scratch tester when $0.2\;{\mu}m$ thickness Cr was coated as interlayer. The micro-hardness was distributed at 35~37 GPa. The friction coefficient was 0.02~0.07, and surface roughness(Ra) was 0.34~1.64 nm. The lifetime of DLC coated plastic injection mold using as a connector part in computer was more than 2 times of non-coated mold.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.570-574
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• 2010

A diamond-like carbon (DLC) film deposited on a WC disk was investigated to improve disk wear resistance for injection molding of zirconia optical ferrule. The deposition of DLC films was performed using the filtered vacuum arc ion plating (FV-AIP) system with a graphite target. The coating processing was controlled with different deposition times and the other conditions for coating, such as input power, working pressure, substrate temperature, gas flow, and bias voltage, were fixed. The coating layers of DLC were characterized using FE-SEM, AFM, and Raman spectrometry; the mechanical properties were investigated with a scratch tester and a nano-indenter. The friction coefficient of the DLC coated on the WC was obtained using a pin-on-disk, according to the ASTM G163-99. The thickness of DLC films coated for 20 min. and 60 min. was about 750 nm and 300 nm, respectively. The surface roughness of DLC films coated for 60 min. was 5.9 nm. The Raman spectrum revealed that the G peak of DLC film was composed of $sp^3$ amorphous carbon bonds. The critical load (Lc) of DLC film obtained with the scratch tester was 14.6 N. The hardness and elastic modulus of DLC measured with the nano-indenter were 36.9 GPa and 585.5 GPa, respectively. The friction coefficient of DLC coated on WC decreased from 0.2 to 0.01. The wear property of DLC coated on WC was enhanced by a factor of 20.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.459-463
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• 2000

Direct use of negative ions for modification of materials has opened new research such as charging-free ion implantation and new materials syntheses by pure kinetic bonding reactions. For these purposes, a new solid-state ce-sium ion source has been developed in the laboratory scale. In this paper, diamond like carbon(DLC) films were prepared on silicon wafer by a negative cesium ion gun. This system does not need any gas in the chamber; deposition occurs under high vacuum. The ion source has good control of the C- beam energy(from 80 to 150eV). The result of Raman spectrophotometer shows that the degree of diamond-like character in the films, $sp^3$ fraction, increased as ion beam energy increases. The nanoindentation hardness of the films also increases from 7 to 14 GPa as a function of beam energy. DLC films showed ultra-smooth surface(Ra~1$\AA$)and an impurity-free quality.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.183-183
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• 2012

In the era of 45 nm or beyond technology, conventional etch mask using photoresist showed its limitation of etch mask pattern collapse as well as pattern erosion, thus hard mask in etching became necessary for precise control of etch pattern geometry. Currently available hard mask materials are amorphous carbon and polymetric materials spin-on containing carbon or silicon. Amorphous carbon layer (ACL) deposited by PECVD for etch hard mask has appeared in manufacturing, but spin-on carbon (SOC) was also suggested to alleviate concerns of particle, throughput, and cost of ownership (COO) [1]. SOC provides some benefits of reduced process steps, but it also faced with wiggling on a sidewall profile. Diamond like carbon (DLC) was also evaluated for substituting ACL, but etching selectivity of ACL was better than DLC although DLC has superior optical property [2]. Developing a novel material for pattern hard mask is very important in material research, but it is also worthwhile eliminating a potential issue to continuously develop currently existing technology. In this paper, we investigated in-situ dry-cleaning (ISD) monitoring of ACL coated process chamber. End time detection of chamber cleaning not only provides a confidence that the process chamber is being cleaned, but also contributes to minimize wait time waste (WOW). Employing Challenger 300ST, a 300mm ACL PECVD manufactured by TES, a series of experimental chamber cleaning runs was performed after several deposition processes in the deposited film thickness of $2000{\AA}$ and $5000{\AA}$. Ar Actinometry and principle component analysis (PCA) were applied to derive integrated and intuitive trace signal, and the result showed that previously operated cleaning run time can be reduced by more than 20% by employing real-time monitoring in ISD process.

• Journal of the Korean institute of surface engineering
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• v.54 no.2
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• pp.53-61
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• 2021

The properties of tetrahedral amorphous Carbon (ta-C) film can be determined by multiple parameters and comprehensive effects of those parameters during a deposition process with filtered cathodic vacuum arc (FCVA). In this study, Taguchi method was adopted to design the optimized FCVA deposition process of ta-C for improving deposition efficiency and mechanical properties of the deposited ta-C thin film. The influence and contribution of variables, such as arc current, substrate bias voltage, frequency, and duty cycle, on the properties of ta-C were investigated in terms of deposition efficiency and mechanical properties. It was revealed that the deposition rate was linearly increased following the increasing arc current (around 10 nm/min @ 60 A and 17 nm/min @ 100A). The hardness and I_D/I_G showed a correlation with substrate bias voltage (over 30 GPa @ 50 V and under 30 GPa @ 250 V). The scratch tests were conducted to specify the effect of each parameter on the resistance to plastic deformation of films. The analysis on variances showed that the arc current and substrate bias voltage were the most effective controlling parameters influencing properties of ta-C films. The optimized parameters were extracted for the target applications in various industrial fields.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.363-366
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• 2003

In nanomachining processes, chemical effects are more dominant factor compared with physical deformation. For example, during the nanoscratch on a silicon surface in the atmosphere, micro protuberances are formed due to the mechanochemical reaction between the diamond tip and the surface. On the contrary, in case of chemically stable materials, such as ceramics or glasse, the surface protuberance are not formed. The purpose of this study is to understand effects of the mechanochemical reaction between tip and surfaces on deformation behaviors of hard-brittle materials. Nanometerscale elasoplastic deformation behavior of single crystal silicon (100) was characterized with the surface protuberance phenomena, and compared with that of borosilicate (Pyrex glass 7740).