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Interactions between plasmas produced by a nitrogen ion beam source and the pulsed laser ablation of an Al2O3 target were studied for the growth of Al-O-N films. Plasma fluxes from both sources were intersected on the substrate surface in a typical arrangement for ion beam assisted pulsed laser deposition (IBPLD). Plasma emission imaging and spectroscopic analyses were performed in real time, using laser pulses for analysis synchronization while varying the N2 background pressure in the range from 0.08 to 4 Pa. This study was focused on the detection of temporal and spatial plasma distributions, excitation states, and chemical reactions during the IBPLD process which were not present when operating each of the plasma sources separately. Two significant plasma interaction effects were discovered. One was the production of atomic N and O in the near-substrate region, resulting in the formation of NO molecules which then reacted with Al to form Al-O-N. Another was the formation of short-lived plasma channels connecting ion beam and laser-ablated plasmas, which was observed in the 2–4 Pa pressure regime. These channels resulted in plasma bending and shifting from the substrate surface and affected film composition. These findings suggest that the interaction of ion beam and laser ablation plumes in IBPLD might considerably affect plasma chemistry, excitation states, and spatial distribution, thus providing opportunities for the control of deposited film properties. [ABSTRACT FROM AUTHOR]

The growth and structure of fullerene-like CN[SUBx] films produced by laser ablation of graphite in low pressure nitrogen were investigated. Deposition conditions were selected based on investigations of CN and C[SUB2] concentration at the condensation surface, vibrational temperature of CN radicals, and kinetic energies of atomic and molecular species. Films were characterized with x-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, nanoindentation, and stress analyses. The nitrogen content in CN[SUBx] films directly depended on the concentration of CN radicals at the condensation surface. Formation of fullerene-like structures required a high vibrational temperature of these radicals, which was maximized at about 4 eV for depositions at 10 mTorr N[SUB2] and laser fluences of ~7 J/cm[SUP2]. The presence of C[SUB2] had only a minor effect on film composition and structure. Optimization of plasma characteristics and a substrate temperature of 300 °C helped to produce about 1-μm-thick solid films of CN[SUBx] (N/C ratio ≈0.2-0.3) and pure carbon consisting of fullerene-like fragments and packages. In contrast to carbon films, fullerene-like CN[SUBx] films exhibited a high elastic recovery of about 80% in using a Berkovich tip at 5 mN load and indentation depths up to 150 nm. Their elastic modulus was about 160 GPa measured from the unloading portion of an indentation curve, and about 250 GPa measured with a 40 Hz tip oscillation during nanoindentation tests. The difference was related to time dependent processes of shape restoration of fullerene-like fragments, and an analogy was made to the behavior of elastomer polymers. However, unlike elastomers, CN[SUBx] film hardness was as high as 30 GPa, which was twice that of fullerene-like carbon films. The unusual combination of high elasticity and hardness of CN[SUBx] films was explained by crosslinking of fullerene fragments induced by the incorporated... [ABSTRACT FROM AUTHOR]