PECVD of Carbon Nanostructures in Hydrocarbon-Based RF Plasmas (original) (raw)
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Journal of Electrical Engineering, 2010
Synthesis of Carbon Nanostructures by Plasma Enhanced Chemical Vapour Deposition at Atmospheric PressureCarbon nanostructures present the leading field in nanotechnology research. A wide range of chemical and physical methods was used for carbon nanostructures synthesis including arc discharges, laser ablation and chemical vapour deposition. Plasma enhanced chemical vapour deposition (PECVD) with its application in modern microelectronics industry became soon target of research in carbon nanostructures synthesis. Selection of the ideal growth process depends on the application. Most of PECVD techniques work at low pressure requiring vacuum systems. However for industrial applications it would be desirable to work at atmospheric pressure. In this article carbon nanostructures synthesis by plasma discharges working at atmospheric pressure will be reviewed.
Synthesis of carbon nanoparticles in combined RF-DC plasma
Materials Today: Proceedings, 2018
In this work carbon nanoparticles were synthesized in combined RF-DC plasma. To synthesize carbon particles a graphite target was used. The time of synthesis of carbon particles was fixed using a self-bias voltage (V dc). The SEM image and the chemical composition of the samples were obtained, and the particle size distribution was constructed. SEM images show synthesized spherical nanoparticles with diameters from 80 to 500 nm in dependence on plasma parameters. Selfbias voltage dependence on time at different plasma parameters (gas pressure and discharge power) has been obtained. The graph of particle synthesis time and DC voltage was shown. It was determined that the increase of DC voltage leads to the decreasing of particle synthesis time. Thus, one can conclude that growth of particles in plasma medium can be controlled by DC voltage value.
Carbon material deposition by remote RF plasma beam
Surface and Coatings Technology, 2004
Hydrogenated and nitrogenated carbon films were obtained by PECVD with carbon species supplied by acetylene gas injected into an argon or argonynitrogen remote plasma generated by an expanding radiofrequency discharge. The properties of carbon material like the nature of bonds, morphology, surface topography, crystallinity are presented. The reaction pathways linking the precursors with the depositing species, as revealed by emission spectroscopy, are discussed.
Plasma density induced formation of nanocrystals in physical vapor deposited carbon films
Carbon, 2011
The effect of plasma parameters on the nanostructures formed during physical vapor deposition growth of carbon films has been studied. It was shown that the formation and nature of nanostructures strongly depend on plasma density and ion energy during the deposition. High plasma density results in formation of nanocrystals with preferred orientation even at low negative substrate bias (300 V) while at low plasma density higher substrate bias (500 V) is required for the nanocrystals. Moreover, at the same plasma density the nature of the nanostructures strongly depends on the ion energy. At higher ion energies, carbon nanotubes are formed in the microstructure while at lower ion energies, graphitic nanostructures are more stable. It was also found that prior to the formation of preferred orientation, an amorphous layer is formed at the silicon/carbon interface. Through electron energy loss spectroscopy, it is shown that the structure of this layer strongly depends on ion energy during the deposition.
Journal of Applied Physics, 2004
The results of numerical simulations, optical emission spectroscopy ͑OES͒, and quadrupole mass spectrometry ͑QMS͒ of inductively coupled Ar/CH 4 /H 2 plasmas in the plasma enhanced chemical vapor deposition ͑PECVD͒ of self-assembled vertically aligned carbon nanostructures ͑CNs͒ are presented. A spatially averaged ͑global͒ discharge model is developed to study the densities and fluxes of the radical neutrals and charged species, the effective electron temperature, methane conversion factor under various growth conditions. The numerical results show a remarkable agreement with the OES and QMS data. It is found that the deposited cation fluxes in the PECVD of CNs generally exceed those of the radical neutrals.
Formation of carbon nanostructures by the plasma jets: synthesis, characterization, application
Materials Today: Proceedings, 2018
Carbon nanostructures were synthesized without the use of catalysts by the conversion of hydrocarbons in the DC plasma jet system. The samples of carbon nanotubes, nanofibers, graphene, onion like structures have been characterized by electron microscopy, thermal analysis, Raman spectroscopy. An experimental study of the composition of the gas phase with variation of the type of the plasma-forming gas and the type of carbon source was carried out. The synthesized samples have been used in the composition of the functional ceramic and in electrochemical systems.
The electronic structure of carbon films deposited in rf argon–hydrogen plasma
Journal of Electron Spectroscopy and Related Phenomena, 2006
The electronic structure of C films deposited by sputtering a graphite target in rf. Ar-H 2 plasma is investigated by photoemission, Auger emission and electron energy loss spectroscopy (EELS) as a function of the H 2 concentration in the feed gas, referred to as [H 2 ]. Adding hydrogen to the plasma causes the films to change from a graphite-like unhydrogenated structure to a non-graphitic hydrogenated structure. The film mass density, as derived from the + plasmon energy, decreases upon H 2 addition to the gas mixture, goes through a minimum at low [H 2 ] and increases with increasing [H 2 ]. It reveals a non-monotonous behavior of the film H content as a function of [H 2 ], the maximum H incorporation occurring at low [H 2 ]. This appears to be a characteristic of C deposition via graphite sputtering in Ar-H 2 plasma and it is discussed in connection with previous results on the subject.
Diamond and Related Materials, 2006
The links between plasma parameters, discharge, film structure and properties are not really yet understood for amorphous hydrogenated carbon layers (a-C:H) plasma deposition. Here, a-C:H layers are deposited in a dual radio-frequency-multipolar microwave plasma excited by distributed electron cyclotron resonance reactor at low CH 4 pressure. This study deals with the plasma analysis, the film characterization and with plasma parameters effect on a-C:H films deposition, structure and properties. The discharge analysis shows that CH 4 is decomposed in CH y1 + H radicals and that C 2 H 2y2 are present in the discharge. As at low pressure, recombination can only take place on the surface, C 2 H 2y2 desorbs from the surface. Moreover, C 2 species are observed attributed to C 2 H 2y2 dissociation. The evolution of film composition with plasma power shows that the proportion of sp 2 CC decreases in contrast with those of CH bonds which increases. From these observations, a phenomenological model for a-C:H deposition can be proposed. Finally, properties are correlated with the film structure and the effect of MW plasma power can then be given.
DC discharge plasma studies for nanostructured carbon CVD
Diamond and Related Materials, 2003
A synthesis of carbon films by d.c. discharge plasma-enhanced chemical vapor deposition using a hydrogen-methane gas mixture was investigated by optical emission spectroscopy and by measurements of current-voltage dependencies. The effects of gas composition and pressure on the characteristics of d.c. discharge in the methane-hydrogen gas mixture are studied. Variation of the deposition process parameters over a wide range allows us to obtain various carbon thin film materials, whose structure and composition were qualitatively characterized by Raman spectroscopy and electron microscopy. The data of optical emission spectroscopy show the presence in the discharge plasma of H, H , CH and C activated species, which play a decisive role in 2 2 nanostructured graphite-like carbon film formation and carbon condensation in the gas phase. We propose a model for the formation of graphitic nanostructured carbon films in plasma containing C dimers. 2