The results of numerical simulations, optical emission spectroscopy (OES), and quadrupole mass spectrometry (QMS) of inductively coupled Ar/CH4/H2 plasmas in the plasma enhanced chemical vapor deposition (PECVD) of self-assembled vertically aligned carbon nanostructures (CNs) are presented. A spatially averaged (global) 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.

No abstract

Articles you may be interested inMicrowave plasma enhanced chemical vapor deposition of nanocrystalline diamond films by bias-enhanced nucleation and bias-enhanced growth Superhard behaviour, low residual stress, and unique structure in diamond-like carbon films by simple bilayer approach J.Ultrathin ultrananocrystalline diamond film synthesis by direct current plasma-assisted chemical vapor depositionThe possibility of the thermophoretic control of the plasma-grown building units in the plasma-assisted deposition of various carbon-based nanostructures on Ni-based catalyzed Si substrates is reported. It is experimentally demonstrated that varying the near-substrate temperature gradient, one can selectively deposit or levitate the carbon-based nanoparticles grown in the low-temperature reactive plasmas of Ar+ H 2 +CH 4 gas mixtures. When the nanoparticles are levitated in the plasma presheath, the arrays of vertically aligned carbon nanotips are assembled, whereas the enhanced deposition of the building units from the gas phase favors the formation of polymorphous nanostructured carbon films. The experimental observations are supported by the one-dimensional model of the nanoparticle dynamics in the near-electrode area. It is shown that the thermophoretic force is indeed a crucial factor that controls the deposition of the plasma-grown fine particles. The experimental and computation results suggest that it is likely that the aligned carbon nanotip structures are predominantly grown by the molecular or radical units, whereas the plasma-grown nanoparticles are presumably the most important component of polymorphous carbon films.

Different aspects of the plasma-enhanced chemical vapor deposition of various carbon nanostructures in the ionized gas phase of high-density, low-temperature reactive plasmas of Ar+H2+CH4 gas mixtures are studied. The growth techniques, surface morphologies, densities and fluxes of major reactive species in the discharge, and effects of the transport of the plasma-grown nanoparticles through the near-substrate plasma sheath are examined. Possible growth precursors of the carbon nanostructures are also discussed. In particular, the experimental and numerical results indicate that it is likely that the aligned carbon nanotip structures are predominantly grown by the molecular and radical units, whereas the plasma-grown nanoparticles are crucial components of polymorphous carbon films.

No abstract