Growth, structure, and mechanical properties of CNxHy films deposited by dc magnetron sputtering in N-2/Ar/H-2 discharges

Hydrogenated carbon nitride films were deposited by reactive de magnetron s puttering in mixed Ar/N-2/H-2 discharges at temperatures of 100 and 350 deg rees C. The total pressure was kept constant at 0.33 Pa and the gas mixture s were varied in order to study the effect of the hydrogen on the resulting film structure and properties. Chemical sputtering effects taking place du ring deposition were found to be an important factor for the growth and str uctural evolution. When H-2 is mixed into the discharge gas, the growth rat e decreases considerably and the films become denser due to desorption of v olatile species, like hydrocarbons, NH3 and HCN. For a H-2 fraction above 1 5%, no net film growth takes place. The hydrogen concentration incorporated into the films was highest (up to similar to 33 at. %) for low growth temp eratures and low nitrogen concentrations. Furthermore, the results indicate that substantial amount of hydrogen are bonded to nitrogen. The incorporat ion of hydrogen in the structure interrupts the relatively long basal plane s in graphite-like structures, and some regions transform into an amorphous structure. Nanoindentation measurements of the film showed decreased elast icity, as well as decreased hardness when,incorporating hydrogen. However, fullerene-like films grown at 350 degrees C in N-2/H-2 discharges exhibit h igh elasticity for H-2 partial pressures as high as similar to 10(-3) Pa du e to low H incorporation into these films. (C) 2000 American Vacuum Society . [S0734-2101(00)03905-1].