The bonding in a series of unhydrogenated amorphous carbon films has been analyzed quantitatively using Raman spectroscopy excited by laser light in both the visible and ultraviolet regions of the spectrum. The asymmetry of the peak near 1550 cm−1 in the visible Raman spectra is correlated with the percentage of sp3 bonding in the films. The ultraviolet Raman spectra exhibit two broad Raman peaks at 1650 and 1100 cm−1, due to sp2 and sp3 vibrational modes, respectively. The former is a resonance feature associated with a large proportion of paired sp2 sites, while the latter is a weighted phonon density-of-states for the distorted random network of sp3 sites. The position and relative intensity of the two peaks are shown to be strongly correlated with the percentage of sp3 sites in the films, providing a reliable measure of sp3 bonding which is both semiquantitative and nondestructive.

Global electric properties, distributions of the induced electromagnetic fields, electron density, temperature, and plasma potential in the 500 kHz planar-coil inductively coupled plasma source have been investigated. The transitions between the two (E and H) discharge operating regimes with variation of input power and operating gas pressure have been demonstrated. It has been shown that the E↔H transitions are accompanied by the resonant minima in the rf power reflection coefficient, which are characteristic for mode jumps in electron cyclotron resonance and microwave slot-excited discharges. The optical emission spectra of argon atoms and ions together with global power balance arguments suggest that the step-wise ionization via the excited states of argon atoms and ions is presumably a mechanism which is responsible for hysteresis. The achieved high plasma density with a high homogeneity level, and low electron temperature and plasma potential imply that the studied plasma source is promising for industrial applications.

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A new Filtered Cathodic Vacuum Arc coating system with a magnetic macroparticle filter design consisting of an off-plane double-bend (OPDB) filter is described. The transport of the vacuum arc plasma through this OPDB filter is investigated using Langmuir and deposition probes. Films of amorphous hard carbon have been deposited a 90° single bend and the OPDB filter and the macroparticle contents of the films are compared. The experimental results were found to be in good agreement with the simulations results based on an improved drift approximation model. The results demonstrate the OPDB filter has a relatively better transmission efficiency than the 90° single bend filter, lower macroparticle counts and is suitable for preparation of diamond-like carbon coatings with high quality. Some important applications of the ta-C coating produced by using the new FCVA system have been identified and where applicable industrial testing results are presented.

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