Deposition Of Carbon Films Research Articles

Inverted fireball deposition of carbon films with extremely low surface roughness

Inverted fireball deposition of carbon films with extremely low surface roughness

The spectral characteristics of plasma-erosion torch on the surface of carbon-bearing materials

The paper obtains spectrograms of the plasma-erosion torch on the surface of the glass carbon in the air and in the vacuum, which allow us to judge the presence of certain particles and their number in the torch depending on the parameters of laser radiation. Experiments have shown that the composition of the plasma-erosion torch in air and in vacuum has a complex structure with different particles, depends on the parameters of laser radiation, which can affect the characteristics and modes of deposition of carbon films.

Deposition of TiO2-Doped Diamond-Like Carbon Films From a New Solution and Their Characterizations

Deposition of TiO2-Doped Diamond-Like Carbon Films From a New Solution and Their Characterizations

Low-pressure hollow cathode plasma source carburizing of AISI 304L austenitic stainless steel at low temperature

A carburizing treatment of AISI 304L austenitic stainless steel was performed at a low temperature of 450 °C using the low-pressure hollow cathode plasma source technique. The hollow cathode plasma was produced in a cathodic cage made of stainless steel screen inlaid with a stainless steel tubes array. A pulsed high voltage power, with a peak voltage of 800 V and a pulse frequency of 30 kHz, was applied at a low gas pressure of 50 Pa. The austenitic stainless steel samples were carburized with a direct current bias of −200 V under the CH4/H2 ratio changing in a range from 0.11 to 9, for a carburizing time of 4 h. Under the lower CH4/H2 ratio of 0.11, a diamond-like carbon film of approximately 260 nm thick formed on the stainless steel surface. As the CH4/H2 ratio increased to 0.67 and 1, both carburizing cases possessed a similar thickness of about 11 μm, with the surface carbon concentration being 6 to 6.5 at.%. A layer of carbon supersaturated face-centered-cubic (γC) phase formed, together with carbon-rich (Fe,Cr)5C2 carbide precipitation. Under the highest CH4/H2 ratio of 9, a single γC phase layer was obtained in a carburizing case of similar thickness, with a high surface carbon concentration of 7.5 at.%. The maximum surface hardness value of HV0.25 N 7.1 GPa occurred on the single γC phase layer. No pitting corrosion occurred on the single γC phase in the polarization curve. The higher passive film resistance and the lower donor and acceptor concentrations and flat band potential indicated that a more compact passive film is grown on the γC phase layer. The (Fe,Cr)5C2 carbide precipitates in the γC phase matrix degraded the passivity of the γC phase layer due to the reduced compactness of the passive film. A carbon transport competition mechanism between carbon adsorption onto the surface and carbon inward diffusion that was mainly dependent on the heavier CHn+ ion bombardment, was proposed to explain the transition with increasing CH4/H2 ratio from carbon film deposition, to a carburizing case composed of ae single γC phase, with both increased hardness and higher corrosion resistance.

Photon excitation effect on formation of graphene nanocrystallites during carbon film growth process

In this article, we propose a method to deposit nanocrystallite embedded carbon films by electron cyclotron resonance plasma sputtering with photon irradiation cooperated with electron or Ar+ ion irradiation. We found photon irradiation can enhance the growth of graphene nanocrystallites during carbon film deposition. The energy transfer from the photon to the metastable carbon structure excites the growth of sp2 hybridized graphene nanocrystallites, and photon-excited electrons can be accelerated by the bias and further promote the graphene nanocrystallite growth. Photons are the second quantum medium we found that can be used to deposit nanocrystallite embedded carbon films, and their quantum properties with electric neutrality can help us to further understand the formation of the carbon nanocrystallite structure and may shed light on the quantum fabrication of desired materials.

Low-Temperature Deposition of Diamond-like Carbon Films Using a Repetitive Nanosecond Pulsed Glow Discharge Plasma Operated in Burst Mode

Low-Temperature Deposition of Diamond-like Carbon Films Using a Repetitive Nanosecond Pulsed Glow Discharge Plasma Operated in Burst Mode

Ultra-high-rate deposition of diamond-like carbon films using Ar/C2H2 plasma jet CVD in combination with substrate-stage discharge

Diamond-like carbon (DLC) films with excellent mechanical properties are used as functional surface protective films for cutting tools. The deposition rate of DLC films using conventional plasma chemical vapor deposition (CVD) methods is several hundred nm min−1. This study applied a negative DC pulsed voltage to a substrate stage irradiated with an Ar/C2H2 mixed plasma jet. The effect of the voltage applied to the stage on the fabricated DLC films was investigated based on the thicknesses and characteristics of the films. DLC films were formed on Si substrates using an Ar/C2H2 plasma jet CVD system. Ar plasma was ejected from a circular nozzle, and C2H2 gas was supplied as a carbon source gas from the center of the circular nozzle. DLC films with a nanoindentation hardness of 17 GPa were obtained by applying −500 V to the stage with a deposition rate of 2140 nm min−1.

HiPIMS pulse shape influence on the deposition of diamond-like carbon films

Two high-power impulse magnetron sputtering (HiPIMS) systems were used to prepare hard DLC films using two types of pulse shape, one normal HiPIMS pulse and the second with short multi-pulse HiPIMS. Similar DLC film performance was achieved, however, recurring to different substrate bias values showing that the pulse characteristics are one determinant factor to the film properties.

Design of thin DLC/TiO2 film interference coatings on glass screen protector using a neon–argon-based gas injection magnetron sputtering technique

This paper reports the results obtained from the deposition of diamond-like carbon (DLC) films on glass substrates by gas injection magnetron sputtering method. The conducted studies aimed to evaluate if the plasma discharge that is generated by varying the proportions of neon−argon (Ne−Ar) gases during pulsed injections (0%–100%) would promote the synthesis of DLC films with desirable sp3 phase by means of electron impact-induced plasma interactions. The obtained DLC films showed the presence of sp3 (CC) hybridized bonds along the Gaussian distribution curve, which revealed that a maximum sp3 content in the range of 32%–45% was obtained along the 40% injection of Ne gas, based on the analysis of the C1s core-level spectra and Raman spectroscopy. A 25% gain in hardness (H) and resistance to cracking (H3/E2) were also observed in the sp3-rich DLC sample (24.1 ± 4 GPa and 0.29 ± 0.04), thus promoting its use in various nanomechanical systems. The change in the sp3/sp2 fraction ratio, demonstrated in this research, corresponded well to a calculated model of graded optical bandgap in the range from 0.53 to 3.01 eV. However, to further minimize the parasitic reflectance from a significant share of sp2 (C=C) domains, thin titanium dioxide (TiO2) (8–36 nm) layers were deposited on the DLC surface, which provided maximum antireflective effect due to interference shift. A significant increase in visible–near-infrared transmittance (up to 87%) was observed as a result of such an interference in DLC/TIO2 bilayers. Our results have practical applications and aid in the design of functional nanocoating structures which are tremendously favored and required to improve the toughness of commercially available glass protectors in hostile environmental conditions.

Structure and Characterization of Vacuum Arc Deposited Carbon Films—A Critical Overview

This critical overview analyzes the relations between deposition conditions and structure for hydrogen-free carbon films, prepared by vacuum arc deposition. The manifold of film structures can be roughly divided into graphitic, nanostructured and amorphous films. Their detailed characterization uses advantageously sp3 fraction, density, Raman peak ratio and the mechanical properties (Young’s modulus and hardness). Vacuum arc deposition is based on energetic beams of carbon ions, where the film growth is mainly determined by ion energy and surface temperature. Both parameters can be clearly defined in the case of energy-selected carbon ion deposition, which thus represents a suitable reference method. In the case of vacuum arc deposition, the relation of the external controllable parameters (especially bias voltage and bulk temperature) with the internal growth conditions is more complex, e.g., due to the broad energy distribution, due to the varying “natural” ion energy and due to the surface heating by the ion bombardment. Nevertheless, some general trends of the structural development can be extracted. They are critically discussed and summarized in a hypothetical structural phase diagram in the energy-temperature plane.

Study of the influence of diamond-like carbon film deposition technology on the change of its physical and mechanical characteristics

The paper presents the results of testing the technology of deposition of diamond-like carbon films on the surface of stainless steel substrates at different process parameters, a quantitative assessment of the sp3 bond content and the physical and mechanical characteristics of the coatings obtained, a conclusion about the influence of the deposition process technological parameters on these characteristics is formulated.

Enhancement of the ion flux to the substrate through high-voltage biasing in an electron cyclotron resonance plasma and its application to high-speed deposition of conductive carbon film

A method for enhancing ion flux to the substrate via high-voltage pulse biasing is investigated in an electron cyclotron resonance plasma. When high-voltage pulse biases above 500 V are applied to the stage, an increase in the stage current is observed, especially in the case of diverging magnetic field configurations in front of the bias stage. The growth and decay time constants of the plasma density and emission intensity are evaluated using a time-resolved Langmuir probe and emission spectroscopy while the pulse is on, and the enhancement of the ionization rate during the bias application is estimated using the zero-dimensional global model. The estimated density enhancement from the model is in good agreement with the measured one. From the numerical simulation of secondary electron trajectory, it is concluded that the electron confinement from the magnetic field is the key factor in plasma density enhancement during stage biasing. Using the high-density plasma produced by the bias voltage, conductive carbon is deposited at a high deposition rate of ∼4 nm s−1.

Noble gas control of diamond-like content and compressive stress in carbon films by arc-mixed mode high power impulse magnetron sputtering

Conventional DC magnetron sputter deposition from a carbon target with argon as the sputtering gas is limited by a low deposition rate, and the resultant coatings have low diamond-like sp 3 content. Here we study arc-mixed mode high power impulse magnetron sputtering (HiPIMS) of carbon using He, Ne, Ar, Xe and Kr gases and show an increase in deposition rate is achieved by using noble gases heavier than argon. On the other hand, a higher sp 3 fraction is achieved by using noble gases lighter than argon. The higher deposition rate of the heavier noble gases is attributed to the higher sputtering yield and an earlier arc onset owing to their lower ionization potential . The higher sp 3 fraction achieved by lighter noble gases is attributed to stress generation by knock-on collisions at the surface of the depositing film, in the absence of stress relief created by large thermal spike volumes. When neon was used as the sputtering gas, the inert gas content was higher than for any other noble gas. Our results lead to opportunities for grading the sp 3 content with depth simply by changing the gas composition, allowing fabrication of buried conductive channels in ta-C, Metal-Insulator-Metal (MIM) (low sp 3 /high sp 3 /low sp 3 ) structures and biosensor films (high sp 3 /low sp 3 ). • Arc-mixed mode HiPIMS deposition of carbon films with He, Ne, Ar, Xe, and Kr noble gases. • The highest sp 3 fraction is achieved by He-Ne mixtures, attributed to effective momentum transfer. • The density and compressive stress in the films decrease with increasing size of noble gas atoms. • The results suggest creating buried conduction channels by changing the sputter gas composition.

Pulsed laser deposition of multilayer diamond-like carbon film grown on stainless steel

The amorphous SiC layers played an essential role of improving adhesive property in the pulsed laser deposition-grown multilayer DLC coating. Comparison of several experiments exhibited that the adhesive SiC layer enhanced the adhesive strength of the DLC layer on the transitional Ti layer. Meanwhile, the ‘inserted’ buffer thin SiC layers, which had strong binding force with the DLC layers, divided the thick DLC layer (about 1.2 μm) into several relatively thin layers. It's thought that the buffer SiC layers reduced accumulation of internal stress in each finite thickness and then prevented the cracking of the DLC layer. And the total thickness of optimized multilayer DLC coating reached to 2 μm. The multilayer DLC coating with the adhesive SiC layer and buffer SiC layers showed an excellent adhesive performance on the stainless steel. The similar tribological property of SiC layer to the DLC layer conferred this multilayer DLC coating a low friction coefficient and a low wear rate.

Acetone and isopropanol – a new liquid precursor for the controllable transfer- and lithography-free CVD of graphene-like films

Liquid precursors are of high practical interest for the chemical vapor deposition (CVD) of graphene and related materials. In terms of cost, safety and technological operability, the liquids are significantly more attractive than the conventional gas precursors. Another challenge to the technology is the direct deposition of carbon films on dielectric substrates without the transfer procedure. In the present work, we study the synthesis of graphene-like films (GLFs) on sapphire and SiO2/Si from two liquid precursors: acetone and isopropanol. GLFs in this work are defined as multi-layer graphene films with a crystallite size of several tens of nm. The films synthesized by CVD at different temperatures were characterized by the optical transmittance and sheet resistance; the structure of the films was studied by Raman spectroscopy. We show that such films have superior characteristics as compared to most literature data on direct CVD deposition from oxygen-containing liquid precursors. The films can be grown selectively on exposed areas of the e-beam pre-patterned substrate at specific deposition conditions. We demonstrate this by selectively growing a Hall bar microstructure for carrier mobility measurements.

Effects of Substrate Bias Voltage on Structure of Diamond-Like Carbon Films on AISI 316L Stainless Steel: A Molecular Dynamics Simulation Study.

With the recent significant advances in micro- and nanoscale fabrication techniques, deposition of diamond-like carbon films on stainless steel substrates has been experimentally achieved. However, the underlying mechanism for the formation of film microstructures has remained elusive. In this study, the growth processes of diamond-like carbon films on AISI 316L substrate are studied via the molecular dynamics method. Effects of substrate bias voltage on the structure properties and sp3 hybridization ratio are investigated. A diamond-like carbon film with a compact structure and smooth surface is obtained at 120 V bias voltage. Looser structures with high surface roughness are observed in films deposited under bias voltages of 0 V or 300 V. In addition, sp3 fraction increases with increasing substrate bias voltage from 0 V to 120 V, while an opposite trend is obtained when the bias voltage is further increased from 120 V to 300 V. The highest magnitude of sp3 fraction was about 48.5% at 120 V bias voltage. The dependence of sp3 fraction in carbon films on the substrate bias voltage achieves a high consistency within the experiment results. The mechanism for the dependence of diamond-like carbon structures on the substrate bias voltage is discussed as well.

Comparison of formation of carbon on aluminum and graphite substrates by a low energy plasma focus device

Characterization of carbon structure was studied through deposition of carbon films on three different substrates at various angular positions. The thin films were prepared by a low energy plasma focus device and placed on graphite, aluminum, and magnesium substrates. The deposition process performed in presence of an active, as well as a noble gas, namely nitrogen and argon. The synthesis of thin films deposited at lower angular position shows nano-crystalline graphite and amorphous carbon structures. A carbon crystal has been detected for deposition at higher angular positions. The characterization of the crystal was investigated and it was revealed that the deposited thin film has hexagonal crystal structure. Further study of crystal led to the conclusion that it can be categorized under crystalline aromatic network. The surface of all synthesized films containing crystalline aromatic network was yellowish orange color (golden). The characterization of each structure was verified by x-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), nano-indentation, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) analyses. Raman spectroscopy was used as a base analysis to classify carbon structures. Raman parameters of natural graphite structure, such as G peak position and ID/IG ratio, as well as, those of carbon crystal, nano-crystalline graphite, and amorphous carbon were identified.

Electronic conductive and corrosion mechanisms of dual nanostructure CuCr-doped hydrogenated carbon films for SS316L bipolar plates

The carbon-coated metal bipolar plate is believed to be a potential substitute of the traditional graphite bipolar plate. However, instead of pyrolytic graphite, carbon films grown by using hydrocarbon as the carbon source have a higher deposition rate but lower conductivity. Aiming to resolve this complaint, here, a new strategy of in-situ catalytic decomposition of methane via reactive magnetron sputtering of a Cr0.6Cu0.4 target in methane and argon atmosphere was proposed without heating. A dual structure C18.6Cr0.06Cu (S65) film with graphene-like carbon bridged nano-Cu clusters within amorphous carbon clusters embedded, which has a deposition rate (~24.1 nm/min) about four times higher than other reports (≤6.2 nm/min), with the interface contact resistance of 7.34 mΩ cm2. The distinct mechanisms of good conductive and anti-corrosion can be understood as (1) the bridged nano-Cu clusters and graphene-like carbon structures construct an interconnected network in the bulk S65 film, endowing the S65 good conductivity, (2) the nano-Cu clusters are isolated by the graphene-like carbon structures and amorphous carbon clusters, which protect the nano-Cu clusters un-contacting with the corrosive medium, bringing the S65 excellent anti-corrosion properties. Our work opens a new route for the rapid deposition of carbon film for bipolar plate application.

High-speed deposition of graphite-like carbon film by Ar/C6H6 surface-wave plasma with high-voltage pulse biasing

A method for graphite-like carbon (GLC) deposition using Ar/C6H6 surface-wave plasma (SWP) is proposed. Characteristic of the SWP, i.e., high plasma density with wide spatial uniformity realized uniform carbon film deposition at high deposition rates. To increase sp2 ratio in carbon films, a pulsed negative bias voltage up to ~2 kV is applied to a substrate. Conductive carbon films of low sheet resistances below ~102 Ω/sq is achieved at high deposition rates up to ~6 nm/s with good spatial uniformity (±5%) in an area of ~18×3 cm2. Film structure is evaluated by Raman spectroscopy, Fourier-transform infra-red spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning transmission electron microscopy and electron energy loss spectroscopy. At high negative bias voltages, sp2-rich with reduced hydrogen content of the film is observed.

Investigation of Surface Layers of Titanium Alloy VT6 with Deposited Carbon Film under Ion-Beam Stirring

Investigation of Surface Layers of Titanium Alloy VT6 with Deposited Carbon Film under Ion-Beam Stirring