Carbon material deposition by remote RF plasma beam (original) (raw)
Related papers
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.
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.
Role of carbon atoms in the remote plasma deposition of hydrogenated amorphous carbon
Journal of Applied Physics, 2003
Closed-loop control of laser assisted chemical vapor deposition growth of carbon nanotubes J. Appl. Phys. 112, 034904 (2012) Enhanced tunnel transport in disordered carbon superlattice structures incorporated with nitrogen J. Appl. Phys. 111, 123711 (2012) Migration mechanism for atomic hydrogen in porous carbon materials Appl. Phys. Lett. 100, 203901 (2012) Field emission from single-, double-, and multi-walled carbon nanotubes chemically attached to silicon
PECVD of Carbon Nanostructures in Hydrocarbon-Based RF Plasmas
Contributions to Plasma Physics, 2005
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.
physica status solidi (a), 2010
Plasma enhanced chemical vapour deposition technique (PECVD) was used to grow diamond-like carbon films using pure methane gas plasma. Structural, optical and mechanical properties of the obtained a-C:H films were investigated as a function of bias voltage in the range 120-270 V, using different techniques. Elastic recoil detection analysis (ERDA) was employed to determine the hydrogen content and Fourier transform infrared spectroscopy (FTIR) was used to analyse the absorption of optically active hydrogen in the deposited films. The relative concentrations of sp 2 and sp 3 groups were determined from fitting of both X-ray photoelectron spectroscopy (XPS) and FTIR spectra. Mechanical hardness and optical transmission were determined using nanoindentation and spectrophotometry, respectively. The results showed that the structure and properties of the films formed strongly depended on the applied bias voltage. In the range of energy considered the growth of the films was governed by a competition between both chemical and physical processes, with a dominance of physical process (subplantation) above 240 V, the energy at which more than 90% sp 3 hybridization was obtained. Nanoindentation tests revealed hardness and Young's modulus of the films ranging from 12-15 and 116-155 GPa, respectively. The optical gap values deduced from the optical transmission spectra varied between 1.13 and 1.60 eV.
Single-beam plasma source deposition of carbon thin films
Review of Scientific Instruments
A single-beam plasma source was developed and used to deposit hydrogenated amorphous carbon ( a-C:H) thin films at room temperature. The plasma source was excited by a combined radio frequency and direct current power, which resulted in tunable ion energy over a wide range. The plasma source could effectively dissociate the source hydrocarbon gas and simultaneously emit an ion beam to interact with the deposited film. Using this plasma source and a mixture of argon and C2H2 gas, a-C:H films were deposited at a rate of ∼26 nm/min. The resulting a-C:H film of 1.2 µm thick was still highly transparent with a transmittance of over 90% in the infrared range and an optical bandgap of 2.04 eV. Young’s modulus of the a-C:H film was ∼80 GPa. The combination of the low-temperature high-rate deposition of transparent a-C:H films with moderately high Young’s modulus makes the single-beam plasma source attractive for many coatings applications, especially in which heat-sensitive and soft materia...
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1992
Hard a-C:H films were grown in a dual frequency plasma sustained simultaneously by microwave and radio-frequency power. "Optimum" growth conditions, namely those leading to the most pronounced sp3 structural features in the films, depend very strongly on the methane feed gas flow rate and on the argon concentration, in the case of CH 4 / Ar mixtures. These optimum conditions have been found to correspond to maximum values of ion flux at the growing film surface, and high concentrations of precursor species such as CH, C2> C 3 , and atomic hydrogen in the plasma, as revealed by optical emission spectroscopy. Films grown under optimum conditions have very high microhardness (~50 GPa), high density (1.8 g/cm-3), and low internal stress (0.5 GPa). Addition of argon to the methane is shown to enhance the gas phase fragmentation and to raise the microhardness, but argon atoms trapped in the films' structure increase the internal stress.
Journal of technological and space plasmas, 2023
Electrically conductive nitrogen-doped hydrogenated carbon films (a-C:H:N) were deposited using a nitrogen-acetylene gas mixture by plasma-assisted chemical vapor deposition (PACVD). A capacitively coupled plasma beam source was used for the depositions. The plasma is excited by a radio-frequency (RF) discharge and confined by Helmholtz magnetic coils, resulting in an increase in plasma density. The ion energy, as well as the deposition rate, can be controlled by the choice of the size of the coupling electrode, i.e. the ratio of cathode-to-anode area, the electric current at the Helmholtz magnet coils, the total gas pressure and the RF power. The interdependence of these process parameters on the ion energy and the deposition rate has been studied in detail in this work. Hardness and electrical resistivity were measured on the deposited a-C:H:N films.