Pressure Plasma Chemical Vapor Deposition Research Articles

Silicon Dioxide Deposited Using Atmospheric Pressure Plasma Chemical Vapor Deposition for Improved Adhesion and Water Intrusion Resistance for Lightweight Manufacturing

This work aims to demonstrate the barrier coating, and adhesion promoting properties of silica-based coatings deposited using an atmospheric pressure plasma torch (APPT). This is achieved by applying an industrial grade adhesive to silica thin films deposited, on the surfaces to be joined, using atmospheric pressure plasma chemical vapor deposition (APP-CVD), to make single joint lap shear samples of different metal combinations commonly found in lightweight manufacturing, such as aluminum and magnesium as well as steel. To deposit these thin films, two separate silicon based organic precursors, hexamethyldisiloxane (HMDSO), and tetraehylorthosilicate (TEOS), are used. Samples are bonded using DuPont Betamate 1486 adhesive, and the lap shear results for these films are compared to the lap shear results of a chemically cleaned control using the same adhesive. The APPT uses a microwave power supply and gas mixtures of N2 and Ar. The adhesion of the films are tested using lap shear, and elevated temperature water soaks are conducted on the joints as well to simulate environmental exposure. Lap shear results, from samples with silica thin films, have an increase of max shear stress of 25%-115% compared to control samples depending on material. After exposure to water soak the max shear strength of the joints decreased by less than 15%, which demonstrates the films capabilities as a water barrier. Film morphology is examined using Scanning Electron Microscopy (SEM), and the film's composition and approximate thickness are obtained using Rutherford Backscattering Spectroscopy (RBS).

Site‐selective atmospheric pressure plasma‐enhanced chemical vapor deposition process for micrometric deposition of plasma‐polymerized methyl methacrylate

AbstractAn atmospheric pressure plasma chemical vapor deposition process designed for the site‐selective deposition of organic functional materials with a sub‐millimetric lateral resolution is presented in this study. Injecting methyl methacrylate vapor in plasma post‐discharge allowed to synthesize plasma‐polymerized methyl methacrylate (ppMMA) coatings on metallic, dielectric, and polymer substrates at close to room temperature (40°C). A circular dot, as small as 400 µm in diameter, of ppMMA is deposited and characterized by Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and high‐resolution mass spectrometry. Oligomeric species of poly‐MMA up to n = 18 have been detected, evidencing the particularly “soft” polymerization offered by the presented process.

Atmospheric Pressure Plasma Chemical Vapor Deposition of Carvacrol Thin Films on Stainless Steel to Reduce the Formation of E. Coli and S. Aureus Biofilms.

In this paper, we have investigated the deposition of thin films from natural carvacrol extract using dielectric barrier discharge (DBD) plasma polymerization, aiming at the inhibition of bacteria adhesion and proliferation. The films deposited on stainless steel samples have been characterized by scanning electron microscopy, infrared reflectance-absorbance spectroscopy, profilometry, and contact angle measurements. Films with thicknesses ranging from 1.5 μm to 3.5 μm presented a chemical structure similar to that of carvacrol. While the formation of biofilm was observed on untreated samples, the coating completely inhibited the adhesion of E. coli and reduced the adhesion of S. aureus biofilm in more than 90%.

Raising the permanent adhesion of coatings on resinous wood by APPCVD promotion

Some resinous woods are preferred for outdoor use due to their durability and long-term stability. Nevertheless, resinous woods are known to generate trouble with coating adhesion after a certain time in outdoor use, resulting in coating detachment and/or microbial infestation. To overcome this problem, the application of atmospheric pressure plasma chemical vapour deposition (APPCVD) as primer – instead of a commercially available impregnation agent – was established to raise the permanent adhesion of a subsequent applied functional coating, such as glaze or lacquer. Results regarding blue stain protection and long-term stability of the resinous woods larch, Douglas fir, and Scots pine protected by an APPCVD primer and a subsequent layer of glaze/lacquer are discussed. This is also done in comparison to a state-of-the-art protection.

Spectroscopic study of an atmospheric pressure plasma generated for the deposition of titanium dioxide thin films

TiO2 thin films are applied in various domains, e.g. air or water purification, self-cleaning surfaces etc. The deposition of titanium dioxide at industrial scale remains challenging. Atmospheric pressure plasma chemical vapor deposition methods are currently developed to provide an easy and viable method for deposition at industrial scale. Even though those methods lead to promising applicative coatings their formation mechanisms remain poorly investigated. In order to investigate the effect of the plasma parameters, i.e. plasma power and introduction of oxygen, on the plasma chemistry, optical emission spectroscopy (OES) is employed to monitor the various species present in the discharge. X-ray Photoelectron Spectroscopy (XPS) analyses of the deposited thin films are carried out and show that by either decreasing the plasma power or introducing oxygen the carbon impurities in the layer can be reduced. By comparing OES and XPS data, the ratio of carbon containing species (CH and C2) to oxygen, i.e. ICH/IO or IC2/IO, in the discharge is shown to be related to the carbon/oxygen composition ratio in the layer.

Antibacterial Silicon Oxide Thin Films Doped with Zinc and Copper Grown by Atmospheric Pressure Plasma Chemical Vapor Deposition.

Zn-doped and Cu-doped SiOx films were synthesized by atmospheric pressure plasma chemical vapor deposition to study their antibacterial efficiency against Gram-negative Escherichia coli and their cytotoxic effect on the growth of mouse cells. Zn-rich and Cu-rich particles with diameters up to several microns were found to be homogeneously distributed within the SiOx films. For both doping elements, bacteria are killed within the first three hours after exposure to the film surface. In contrast, mouse cells grow well on the surfaces of both film types, with a slight inhibition present only after the first day of exposure. The obtained results indicate that the films show a high potential for use as effective antibacterial surfaces for medical applications.

Thin antimicrobial silver, copper or zinc containing SiOx films on wood polymer composites (WPC) applied by atmospheric pressure plasma chemical vapour deposition (APCVD) and sol–gel technology

Microbial colonization of wood and wood polymer composites (WPC) by bacteria and mould can cause aesthetic damage, negative impact on mechanical properties or even health hazards. This work investigated the structural morphology, elemental composition and antimicrobial properties of thin functional silicon oxide films deposited on WPC using atmospheric pressure chemical vapour deposition (APCVD) and sol–gel technology. Scanning electron microscopy results indicated the creation of flat, thin and closed films on top of the surface of this material. By embedding of active agents such as silver, copper or zinc, the APCVD films became slightly rougher. The corresponding sol–gel-films showed a certain number of cracks. The elemental composition of the films was investigated by X-ray photoelectron spectroscopy and depth profiling indicating the integration of active agents into the created SiOx film matrices. Moreover, the possibility to generate combinations of active agents in one layer could be demonstrated. BacTiter-Glo® tests as a part of antibacterial investigations showed strong bactericidal properties for silver and copper as well as sufficient properties for zinc-containing layers against Escherichia coli. Antimycotic effects on mould strains Aspergillus niger, Paecilomyces variotii, Penicillium funiculosum and Trichoderma viride were low for films containing only one active agent. Significant improvements in activity were achieved by the combination of these active agents.

Effects of dilution gas on characteristics of SiOC(H) films synthesized by atmospheric pressure plasma CVD

In this study, we synthesized SiOC(H) films by atmospheric pressure plasma enhanced CVD from trimethylsilane and oxygen gas diluted by helium, argon and nitrogen. We changed the oxygen flow rate and investigated the effect of dilution gas on the hardness of the films. The deposition rate for both helium and argon dilution increased with increasing the oxygen flow rate up to 100 ml/min. The hardness of the films diluted by argon gradually increased from 0.2 GPa to 1.1 GPa with an increase of oxygen flow rate while that of the films diluted by helium was hardly changed about 0.6 GPa. The films diluted by nitrogen exhibited high hardness at 2.3 GPa, which was highest value among the samples. The FT-IR spectra of the films showed the peaks corresponding to terminal methyl and hydroxyl bonds along with the stretching vibrations of SiOSi network bonding were observed and their intensities varied with the hardness of the films. As the oxygen flow rate increased, intensity of methyl bond decreased and that of hydroxyl bond was not increased different from the result of the films diluted by argon or helium gas. The methyl bonds are likely to prevent oxygen atom from forming SiOSi structures. The existence of terminated bonds such as methyl bond and hydroxyl bond lead to low hardness of the films. From the result of optical emission spectroscopy, peaks of nitrogen-oxygen radicals were observed at plasma diluted by nitrogen, while a large amount of oxygen radical were generated in the plasma diluted with noble gas.

Atmospheric pressure plasma chemical vapor deposition reactor for 100 mm wafers, optimized for minimum contamination at low gas flow rates

Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems.

Investigation of contact-induced charging kinetics on variably modified glass surfaces

The accumulation and dissipation of electrical charge on glass surfaces is of considerable academic and industrial interest. The purpose of the present article, is to report on the differences in charging kinetics of several flat alumina-borosilicate (low alkali content) glass surfaces via a rolling sphere test (RST) [1] that have been physically and/or chemically modified by different approaches and exposed to variable environmental conditions (i.e. relative humidity). Methods used for surface modification include chemical etching (HF based chemistries of variable molarity) and plasma processing/thin film deposition (CH4 via Reactive Ion Etch (RIE) and/or Atmospheric Pressure Plasma Chemical Vapor Deposition (APPCVD)). Trends in glass surface charge rates, along with corresponding surface resistivity, energy and zeta potential measurements indicate that glass surface, and perhaps bulk, chemistry (specifically a surface’ reactivity/affinity with/to water) play critical roles in charge dynamics. Based on the results, we propose an ion-based transfer model facilitated by surface–water molecular interactions as the primary mechanism responsible for contact electrification in glass–metal contact systems.

Chemical structure and mechanical properties of glow discharge polymer films and deuterated glow discharge polymer films

Taking advantage of low pressure plasma chemical vapor deposition technology, the hydrocarbon glow discharge polymer (GDP) and deuterated glow discharge polymer (D-GDP) films were fabricated by glow discharge polymerization technology. The deposition rates, the chemical structures and mechanical properties of films were studied by FTIR spectra, surface profiler and nano-indentation. The results show that the deposition rate of GDP/D-GDP almost linearly increases with the increase of gas flow, the deposition rate of GDP films is higher than that of D-GDP films. The cross-link degree of D-GDP films is lower than that in GDP films. The D-GDP films might be more favorable for IR heating on the DT ice of ICF target. The mechanical property of GDP is better than that of D-GDP.

Atmospheric pressure plasma CVD as a tool to functionalise wound dressings.

The main goal of this investigation was the preparation of an antibacterial layer system for additional modification of wound dressings with atmospheric plasma. Furthermore, the modified wound dressings were checked on there bactericidal and cytotoxic activity. The layer system was applied by using a novel atmospheric pressure plasma chemical vapour deposition technique on a variety of textile substrates which are suitable as wound dressing materials. The layer system composed of silicon dioxide with in situ generated embedded silver nanoparticles. The bactericidal activity of the produced wound dressings was investigated against different bacteria like Staphylococcus aureus and Klebsiella pneumoniae while the cytotoxic potential of the coated wound dressings was verified using human keratinocytes. Even at low concentrations of silver precursor a strong antibacterial effect was observed in direct contact with S. aureus and K. pneumoniae. Furthermore, extractions produced from the coated textiles showed a good antibacterial effect. By means of optimised coating parameters a therapeutic window for those wound dressings could be identified. Consequently, the atmospheric pressure plasma chemical vapour deposition technique promise an effective and low cost modification of wound dressing materials.

The Influence of Overaluminizing on TGO Formation on Thermal Barrier Coatings Deposited by Low Pressure Plasma Spraying and Chemical Vapour Deposition Methods on Rene 80 Nickel Superalloy

The paper presents results of research into isothermal oxidation test of thermal barrier coatings characterized by high oxidation resistance and hot corrosion. Bondcoats were deposited by overaluminizing of MeCrAlY–type coating deposited by LPPS method. The outer ceramic layer of yttrium oxide stabilized zirconia oxide (Metco 6700) was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally LPPS-sprayed were MeCrAlY bondcoats, which were not subsequently aluminized.. The isothermal oxidation test at 1100oC for 1000h shown that thickness of the TGO layer in overaluminized bondcoat was significantly thicker in comparison with conventional LPPS-sprayed MeCrAlY bondcoats.

Microstructure of Thermal Barrier Coatings Deposited by Low Pressure Plasma Spraying and Chemical Vapour Deposition Methods on Rene 80 Nickel Superalloy

The paper presents results of research into thermal barrier coatings characterized by high oxidation resistance and hot corrosion. Bondcoats were formed by overaluminizing of an MeCrAlY–type coating deposited by low pressure plasma spraying. The outer ceramic layer of yttrium oxide stabilized zirconia oxide (Metco 6700) was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally LPPS-sprayed were MeCrAlY bondcoats, which were not subsequently aluminized. Used as base material was Rene 80 nickel superalloy. The research has shown that as a result of aluminizing by the CVD method there was formed in the bondcoat a deposit zone built of the β-NiAl phase which protects from oxidation. Preserved below increased chromium content ensures resistance to hot corrosion. The outer ceramic layer was characterized by columnar structure similar to that obtained in the EB-PVD process.

Abrasion resistance of silica-based coatings prepared by atmospheric pressure plasma chemical vapor deposition for protection of polymeric surfaces

Silica-based films were synthesized by the dielectric barrier discharge method under atmospheric pressure from tetramethoxysilane and O2 diluted with N2. In this study, the coating area was 200 mm in diameter, which could be enlarged by altering shape of the electrodes and expanding the scanning range. Even at the low temperature of 80 °C, the hardness of the films slightly increased up to 4.3 GPa by decreasing the tetramethoxysilane flow rate. The relative ratio of Si−O−Si (cage structure) bonds to Si−O−Si (network structure) decreased, and as a result, the films became harder. Additionally, it was found that silica-based films deposited on acrylic resin-coated polycarbonate substrates had good abrasion resistance; the minimum ΔHz value after 1000 revolutions in the Taber abrasion tests was 2.5%. These results suggest that the silica-based films synthesized under atmospheric pressure have the potential to be used in mass production because the equipment enables low-cost and large-area synthesis. The authors find that there is potential in using atmospheric pressure plasma technology for the automobile industry.

Large-Area Organosilicon Film Deposition Using Cyclonic Atmospheric Pressure Glow Discharge

Cyclonic atmospheric pressure plasma is developed for chamberless deposition of organosilicon thin films from argon/hexamethyldisoxane (HMDSO) mixtures. The surface properties of the resulting plasma films were investigated as a function of RF plasma power. Film characterization was performed by static contact angle measurement, scanning electron microscopy (SEM), atomic forced microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). It was found the RF plasma power is the key factor that to affects the film growth in the atmospheric pressure plasma chemical vapor deposition process. SEM and AFM results indicated that a smooth, continuous, and uniform surface of organosilicon thin films can be formed at a relatively low plasma power input. XPS indicated that atmospheric-pressure plasma-deposited organosilicon films present mainly inorganic characteristics. This study shows a potential of chamberless film growth at atmospheric pressure to form organosilicon thin films for large-area deposition.

Low Temperature Deposition of Antibacterially Active Silicon Oxide Layers Containing Silver Nanoparticles, Prepared by Atmospheric Pressure Plasma Chemical Vapor Deposition

AbstractThis study presents investigations to create antibacterially active thin films by using the atmospheric pressure plasma chemical vapor deposition technique. Silver nitrate solutions are sprayed and converted within the plasma to create and implement formed silver nanoparticles into a growing SiOx‐matrix in situ during the deposition step. Investigation of the films on their bactericidal activity using an Escherichia coli (E. coli) strain shows a strong antibacterial effect of the coatings and additionally a good stability against abrasive wear. The films are characterized by X‐ray photoelectron spectroscopy, SEM, energy dispersive X‐ray spectroscopy, and IR spectroscopy. magnified image

Low Friction Property of Diamond-Like Carbon Coating Films and Oxygen Transmission Ratio of Amorphous Carbon Films Deposited by Advanced Coating Processes

The topics of the applied technology of amorphous carbon film to reduce friction using diamond-like carbon (DLC) coated by the vacuum arc ion plating process and to improve the gas barrier property using the amorphous carbon film by the atmospheric pressure plasma process are introduced with the basic experimental results. For reducing friction, the super low friction coefficient below 0.01 has been found when the tetrahedral amorphous carbon coating deposited by T-shape filtered arc deposition method [ta-C(T)] was evaluated the friction property under oleic acid lubrication at pure sliding condition. It was thought that the low share strength tribofilm composed of water and oleic acid mono-layer seemed to be formed on the sliding interface. For gas barrier performance, the amorphous carbon film deposited by the atmospheric pressure plasma chemical vapour deposition (CVD) technique on poly(ethylene terephthalate) (PET) substrate was improved the oxygen transmission ratio (OTR) around 30% compared with that of uncoated PET substrate. These advanced performance obtained by the optimum material combination of DLC with lubricant and the original atmospheric pressure plasma CVD technique are expected to be applied on the actual application for the different types of the industrial fields in near future.

Synthesis of Diamond-Like Carbon Films on Planar and Non-Planar Geometries by the Atmospheric Pressure Plasma Chemical Vapor Deposition Method

Synthesis of Diamond-Like Carbon Films on Planar and Non-Planar Geometries by the Atmospheric Pressure Plasma Chemical Vapor Deposition Method

Anti-adhesion treatment for nanoimprint stamps using atmospheric pressure plasma CVD (APPCVD)

Nanoimprint lithography (NIL) provides a practical method for producing high-precision nanostructures efficiently and at low cost. Interfacial interactions between the imprint stamp and the forming material are crucial for high-quality pattern transfer, with critical dimensions and large aspect ratios. This study conducted an in-depth investigation into anti-adhesion treatments for imprint stamps using atmospheric pressure plasma chemical vapor deposition (APPCVD). Quantitative analyses of adhesion force, surface roughness and contact angle were applied to verify the enhanced imprint capability and release performance of the stamps. Experimental results confirmed that APPCVD-prepared anti-adhesion coatings provided improvements in quality and produced few defects in imprinted replicas. The proposed technique can simultaneously provide surface modification and thin-film deposition, depending on the precursors used. Additionally, the use of oxygen-containing plasma resulted in greater durability of the anti-adhesion coatings. The major advantages of the technique include low-temperature treatments, large-format scalability with good uniformity, short process times, and a non-vacuum process environment.