Radio Frequency Plasma Chemical Vapor Research Articles

Correlation of Cell Proliferation with Surface Properties of Polymer-like Carbon Films of Different Thicknesses Prepared by a Radio-Frequency Plasma CVD Process.

In this study, correlation of cell proliferation with surface properties of the polymer-like carbon (PLC) films of different thicknesses prepared by radio-frequency plasma CVD are investigated. Four PLC samples were prepared via radio frequency plasma chemical vapor deposition on Si substrates. Each PLC film was analyzed using spectroscopic ellipsometry to determine its thickness, refractive index (n), and extinction coefficient (k); the thickness ranged from 29.0 to 356.5 nm. Based on their n–k plots, all the samples were classified as PLC-type films. The biological response of the PLC films was evaluated in vitro using a cell culture. The samples with relatively thick PLC films (>300 nm) exhibited stronger cell proliferation properties than those with thinner films. Moreover, the results of the surface analysis showed no significant differences in the surface composition of those PLC samples, as analyzed using X-ray photoelectron spectroscopy, but that as the PLC films became thicker, their surfaces became rougher on the nanoscale and their wettability improved. Overall, this study showed that careful control of the film growth of PLC films, which affects their surface properties, is essential for their use in bio-interface applications.

Investigation on formation of thin Si-B-N films on stainless steel by plasma chemical vapor deposition

Amorphous Si-B-N alloy films on SS304 stainless steel substrates prepared by using radio frequency plasma chemical vapor deposition (RF-PCVD) from the mixture gases of N2, Ar, B2H6 and SiH4. It is found that both hardness and wear resistance of the samples with film coating were improved significantly. There are N, Si, and B existing in deposited films through the XPS and the FT-IR measurement. SEM images of the film surface presents the morphology of hilly clusters composed of small particles. Energy dispersive spectrometry (EDS) and glow discharge optical emission spectrometry (GD-OES) were used to investigate the early nucleation and growth. At the early growth stage of 5 min, the continuous film formed is composed of small particles with a diameter of tens of nanometers on the substrate, suggesting that the precursor species easily nucleate on the stainless steel surface. The examination of cross-section for film coating indicates that an interface layer with diffusion forms during the deposition process, which is attributed to highly reactive species containing silicon, boron and nitrogen generated in discharging plasma. Those have high enough energy to induce diffusion effect in interface layer.

Tribological behaviour of stainless steel with respect to that of DLC in terms of energetic aspects

The tribological behaviour of stainless steel (SUS 440C) relative to that of diamond-like carbon (DLC) was investigated in terms of tribometer input energy. The DLC was prepared on tungsten carbide (WC) substrates using radio frequency plasma chemical vapour deposition with benzene (C6H6) as a gas source. The stainless steel ball, as the counterpart, was tribotested. The input energy was calculated using the applied load, friction coefficient and sliding distance obtained from each tribotest. The wear loss of the ball increased as the sliding distance increased, whereas wear loss of the DLC was not directly observed. During evaluation of the input energy, the wear rate of the stainless steel ball decreased as the input energy increased. We propose a method for evaluating tribological properties using the input energy and discuss the wear behaviour of the stainless steel based on the input energy.

Study on Deposition of Amorphous DLC-Si Films by RF-PECVD

In this study, we investigated DLC-Si films were deposited by PECVD from C4H10:SiH4:O2 gas mixtures. We aim to investigate the influence of hydrogen on the variation of echanical properties and microstructure of DLC-Si films synthesized by radio frequency plasma chemical vapor deposition (r.f.-PECVD). The DLC films were deposited on a silicon substrate. That the reactant gases employed in this paper are a mixture of composition. The films deposited were studied by atomic force microscope (AFM), Raman and Fourier transform infrared (FT-IR) spectroscopy. The test results show that the ratio of SiH4 in the gas mixture was successively varied to clarify its influence on the roughness, microstructure, hardness, refractive index for the DLC films. The results reveal that the increasing of the concentration of SiH4 increases sp3 ratio, refractive index and roughness. Meanwhile, increasing the SiH4 concentration causes the decrease of hardness. Finally, optic behavior is correlated to the silicon concentration for deposition with SiH4 containing reactant gas.

Relationship between tribological properties and sp3/sp2 structure of nitrogenated diamond-like carbon deposited by plasma CVD

The correlation between the wear resistance and the chemical states of the elements of nitrogenated diamond-like carbon (NDLC) is characterized and discussed in this paper. NDLCs have been deposited on tungsten-carbide, silicon and glass substrates by radio frequency plasma chemical vapor deposition (rf PCVD) from benzene (C6H6)-nitrogen mixtures with four different ratios. The nitrogen concentration in the films measured by electron microprobe analysis was found to be proportional to the nitrogen flow rate. The friction coefficients of the films determined by the ball-on-disk test increased with adding nitrogen contents. Such friction coefficient dependent on load was not observed in each film. The DLC showed adhesive wear. However, the wear mode of NDLCs changed from the adhesive wear to the abrasive wear at the critical load point. The film hardness measured by nano indentation decreased with increasing nitrogen. The sp3/sp2 measured by X-ray photoelectron spectroscopy (XPS) was reduced by adding nitrogen and as a result, the tribological behaviors such as the hardness, the wear resistance and the critical point were also decreased.

Biochip applications of DLC films on a resin material

AbstractRecent studies of diamond‐like carbon (DLC) coated medical devices have indicated possibility for developing biochip applications. We have deposited DLC film on cyclo‐olefin polymer (COP) sheet by using radio frequency plasma chemical vapor deposition technique. To enhance the adhesion strength between the COP sheet and the DLC films, the COP surface was modified by oxygen (O2) or nitrogen (N2) plasma treatment before the film coating. The critical load of samples was measured by using a scratch test. The result showed the adhesion strength of films was improved by the plasma treatment. After the DLC film coating, we performed the plasma post‐treatment of O2, N2 or hexafluoroethane (C2F6) gases to control the wettability of the material surface. The wettability, structure, roughness, and chemical composition of the samples have been investigated by a contact angle measurement, Raman spectroscopy (Raman), atomic force microscopy (AFM), and X‐ray photoelectron spectroscopy (XPS). These measurements indicated that wettability on the surface condition of DLC films was easily controlled by plasma post‐treatment of O2, N2 and C2F6. Furthermore, results of XPS showed that wettability of the surface condition is strongly dependent on chemical components with existemce of oxygen, nitrogen and flourine. We have estimated the wettability of hydorphilicity and hydrophobicity on DLC coating under plasma post‐treatment for biochip applications (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

1003 人工血管への応用を目的とした高分子材料へのDLCコーティングとその物性評価(OS13-(1)オーガナイズドセッション《生体医工学及びバイオマテリアル》)

Diamond like carbon (DLC) film was prepared for on Si, PTFE and PET using a radio frequency (RF) plasma chemical vapor deposition (CVD) device at process pressure of 1-300Pa. In the present study, a nanoindentation and a bending test were performed for evaluating film hardness. For the bending test, the DLC coated on polymer was bended at 90 degrees, and the number of the resulting cracks of the film was counted using a laser-microscope. As a result, the hardness of DLC film decreased with increasing the process pressure.

311 DLC被膜の熱電性能に及ぼす窒素含有率の影響(OS3-(3)オーガナイズドセッション《環境とエネルギー》)

Nitrogen doped diamond like amorphous carbon (DLC) thin films on grass substrate were prepared by radio frequency (rf) plasma chemical vapor deposition (CVD) using CH4 as the source of carbon and with different N_2 flow rates (N2 : CH4 gas ratios between 0 : 100 and 40 : 60), at 270〜300K. The resistivity of the film were measured by Van der pauw method. The nitrogen content in the films was about 3.8-6.0%, obtained from Glow discharge optical emission spectroscopy. The thermoelectric performance of nitrogen doped DLC was increased step by step with increasing nitrogen flow rate. The difference of thermoelectric performance was decreased with the increase temperature.

Amorphous Carbon Film Deposition for Hydrogen Barrier in FeRAM Integration by Radio Frequency Plasma Chemical Vapor Deposition Method

Amorphous carbon (α-C) films were deposited on PbLaZrTiOx (PLZT) capacitors by a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) method. The α-C films of 20nm prepared with different deposition pressure, methane concentration and RF power were investigated as a hydrogen barrier layer for ferroelectric random access memory (FeRAM) integration. The α- C films contained atomic hydrogen as shown by Fourier transform infrared spectrometry (FT-IR) and exhibited a possibility to suppress the hydrogen degradation of ferroelectric properties.

Amorphous Carbon Film Deposition for Hydrogen Barrier in FeRAM Integration by Radio Frequency Plasma Chemical Vapor Deposition Method

not Available.

714 CVD法による作製されたDLC膜の有機分子の吸着特性評価(OS5-(2) インプラントおよび生体材料,オーガナイズドセッション)

Diamond-like carbon (DLC) film was prepared on PTFE using a radio frequency (RF) plasma chemical vapor deposition (CVD), and the surface of the DLC film was treated by NH_3 plasma. The adsorption characteristic of heparin (molecular weight 4000) on the DLC film was examined to improve antithrombogenic properties. The deposited film was identified as DLC using Laser Raman analysis. When the DLC film was treated by NH_3 plasma, self-bias degreased with increasing NH_3 pressure. X-ray photoelectron spectroscopy (XPS) analysis showed that the N-H bond increased with degreasing NH_3 pressure. As the result, the DLC film treated by 10Pa-NH_3 plasma adsorbed the largest amount of heparin.

Microstructure and mechanical properties of Mo/DLC nanocomposite films

Mo-doped diamond-like carbon (Mo/DLC) films were deposited on stainless steel and Si wafer substrates via unbalanced magnetron sputtering of molybdenum combined with inductively coupled radio frequency (RF) plasma chemical vapor deposition of CH 4/Ar. The effects of Mo doping and sputtering current on the microstructure and mechanical properties of the as-deposited films were investigated by means of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, atomic force microscopy (AFM), and nano-indentation. It was found that Mo doping led to increase in the content of sp 2 carbon, and hence decreased the hardness and elastic modulus of Mo/DLC films as compared with that of DLC films. The content of Mo in the films increased with the increasing sputtering current, and most of Mo reacted with C atoms to form MoC nanocrystallites at a higher sputtering current. Moreover, the Mo-doped DLC films had greatly decreased internal stress and increased adhesion to the substrate than the DLC film, which could be closely related to the unique nanocomposite structure of the Mo-doped films. Namely, the Mo/DLC film was composed of MoC nanoparticles embedded in the cross-linked amorphous carbon matrix, and such a kind of nanostructure was beneficial to retaining the loss of hardness and elastic modulus.

Influence of hydrogen on the mechanical properties and microstructure of DLC films synthesized by r.f.-PECVD

This paper aims to investigate the influence of hydrogen on the variation of mechanical properties and microstructure of diamond-like carbon (DLC) films synthesized by radio frequency plasma chemical vapor deposition (r.f.-PECVD). The DLC films were deposited on a silicon substrate ( p-type). The reactant gases employed in this paper are a mixture of acetylene and hydrogen. The ratio of hydrogen in the gas mixture was successively varied to clarify its influence on the roughness, thickness, microstructure, hardness, modulus, residual stress and wear depth for the DLC films. The results reveal that increasing the concentration of hydrogen decreases thickness and roughness. Meanwhile, increasing the hydrogen concentration causes the decrease of sp 3 ratio, hardness as well as modulus. Finally, wear behavior is correlated to the surface morphology and hydrogen concentration for deposition with hydrogen-containing reactant gas.

Correlation between electric parameters of carbon layers and their capacity for field emission

The aim of this work is to study a possibility of field electron emission from carbon layers produced by radio frequency plasma chemical vapor deposition (RF PCVD) method. A correlation between electric parameters of the layers and the ability to produce electron emission is also studied through material (AFM) and electrical (C-V, I-V) characterization of the obtained layers. It is demonstrated that the layers deposited with the highest self-bias exhibit the highest capacity for electron emission.

Investigations of electron emission from DLC thin films deposited by means of RF PCVD at various self-bias voltages

The aim of this paper is to report the results of field emission experiments on undoped, flat diamond-like carbon (DLC) thin films deposited at various self-bias voltages using radio frequency plasma chemical vapor deposition (RF PCVD) technique. It has been observed that the emission properties improve when the absolute value of self-bias voltage becomes higher, e.g., the turn-on field value decreases. The correlation between electron field emission and sp2 content in these films showed improvement of electron emission properties of DLC films for higher amount of sp2 phase.

Chemical analysis of interface area in DLC/Si systems

Diamond-like carbon (DLC) films’ properties depend on their chemical composition, influenced by deposition parameters. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and auger electron spectroscopy (AES) have been used in this study to analyze the chemical composition of DLC films deposited on flat Si substrates using the radio frequency plasma chemical vapor deposition (RF PCVD) method. Carbon, hydrogen and oxygen have been detected in the investigated DLC films. Additionally, high intensity of SiC, Fe and Cr has been detected in the interface region of the DLC and Si substrate, the metallic ions probably originating from metal elements of the RF PCVD reactor chamber.

Hydrogen Permeation through Diamond-Like Carbon Thin Films Coated on PET Sheet

Hydrogen (H2) permeation through diamond-like carbon (DLC) thin films has been investigated by using dynamic observation of H2 leakage through the DLC films into a high vacuum chamber equipped with a quadropole mass spectrometer (QMS). DLC films were deposited on polyethylene terephthalate (PET) sheets using radio frequency (RF) plasma chemical vapor deposition (CVD) method from C2H2 source gas. The specimen was set on the flange of an ultra-high vacuum (UHV) chamber and H2 gas was permeated through the sheet. The permeation of H2 through the 0.3 mm thick PET sheet started within a few minutes and became saturated in the permeation rate within a few hours after the pressure difference was applied. With the 100-nm thick DLC coating, the response of H2 permeation was delayed and the permeation rate was decreased.

Optical effect of diamond‐like carbon film coating of long‐period optical fiber gratings

AbstractThe paper presents diamond‐like carbon (DLC) film as a coating for long‐period grating (LPG) optical fiber structure. The spectral response of a DLC‐coated LPG structure is strictly dependent on Radio Frequency Plasma Chemical Vapour Deposition (RF PCVD) process parameters. The paper discusses the influence of DLC deposition time and self‐bias voltage to shift of the LPG resonance peak and explores the possibility of using the structure as a refractometric sensor. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Selective growth of CNT by using triode-type radio frequency plasma chemical vapor deposition method

Triode-type radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) equipment has been used in order to grow well-aligned carbon nanotubes on Si and glass substrates below 600 °C. This CVD equipment allows the growth of a well-aligned carbon nanotube with an inside and an outside diameter of 7 and 17 nm, respectively. The selective growth of the CNT was demonstrated.

Application of diamond-like carbon films in optical fibre sensors based on long-period gratings

The paper presents diamond-like carbon (DLC) film as a coating for optical fibres with long-period gratings (LPG). The coatings were successfully obtained using the Radio Frequency Plasma Chemical Vapour Deposition (RF PCVD) method. Thin DLC coatings significantly change the properties of the LPG-based sensing elements. The sensing systems built using those elements can be very sensitive to concentration changes of various chemical solutions due to changes in their refractive index. DLC-coated LPGs can be as much as 15 times more sensitive than uncoated LPGs to variations within a specified range of the refractive index of the surrounding medium. The influence of RF PCVD process parameters on sensitivity is discussed.