Controllable-unbalanced de magnetron sputtering of a B4C target in mixed Ar-N-2 discharges has been used to deposit BN:C thin films with carbon concentrations in the range of 5-21 at, % on Si(001) substrates. The variation of the nitrogen gas consumption with nitrogen partial pressure was used to determine the sorption capacity of the sputtering source and was then correlated to the film discharge plasma density near the substrate in a wide range. Hence, the ion flux J(i) of primary Ar+ and N-2(+) ions accelerated to the substrate by an applied negative substrate bias could be varied while keeping the deposition flux J(n) (the sum of film building species, B, C, and N atoms) near constant. BN:C films were grown at large ion-to-neutral flux ratios 3 less than or equal to J(i)/J(n) less than or equal to 24, ion energies E(i) less than or equal to 500 eV, and substrate temperatures 150 less than or equal to T-s less than or equal to 350 degrees C. The phase and elemental composition of as-deposited BN:C films were characterized by Fourier transform infrared spectroscopy and wavelength dispersive x-ray spectroscopy, respectively. Deposition of cubic phase c-BN:C containing 5-7 at. % of C is demonstrated under conditions of low energy (110 eV) ion bombardment, a high ion-to-atom arrival rate ration (J(i)/J(n) similar to 24), and low growth temperatures (similar to 150 degrees C). (C) 1996 American Vacuum Society.

Symmetric CNx/BN:C multilayer thin films, with nominal compositional modulation periods of ? = 2.5, 5, and 9 nm were deposited by unbalanced dual cathode magnetron sputtering from C (graphite) and B4C targets in an Ar/N2 (60/40) discharge. The multilayers and single-layer of the constituent CNx and BN:C compounds were grown to a total thickness of 0.5 µm onto Si(001) substrates held at 225°C and a negative floating potential of approx. 30 V (Ei = 24 eV). Layer characterizations were performed by TEM, X-ray reflectivity, RBS, and nanoindentation measurements. Results show that CN0.33 and BN:C (35, 50, and 15 at.% of B, N, and C, respectively) layers were prepared at the above conditions. It is suggested that all films exhibit a three-dimensional interlocked structure with a cylindrical texture in the film growth direction. The structure was continuous over relatively well defined and smooth CNx/BN:C interfaces. All coatings exhibit extreme elasticity with elastic recoveries as high as 85-90% (10 mN maximum load) attributed to the observed structure. However, the multilayers were stiffer and more elastic compared to that of the single-layers and thus shows promise for improved protective properties.

Box-shaped nanostructures of B-C-N compounds were synthesized by reactive sputtering of boron carbide in mixed argon and nitrogen discharges. Transmission electron microscopy showed that these nanoboxes were grown on self-patterned NaCl substrate with projected areas ranging from similar to 1x10(2) to similar to 5x10(4) nm(2), sizes 50-100 nm, and number density similar to 100 mu m(-2). Electron energy loss spectroscopy revealed a phase separation of BN and C:N layers. (C) 2000 American Institute of Physics. [S0003-6951(00)00507-6].