Structural and mechanical characterization of BC_xN_y thin films deposited by pulsed reactive magnetron sputtering

BC_xN_y thin films deposited at 250°C by pulsed reactive magnetron sputtering of a B₄C target in an Ar/N₂ plasma were studied by elastic recoil detection analysis, FTIR, Raman, and photoelectron spectroscopy, electron microscopy, and nanoindentation. In the concentration range of 6 % to 100 % N₂ in the sputter plasma the segregation into nanocrystalline hexagonal boron nitride and amorphous sp² carbon is the dominant process during the film growth. The stoichiometric ratio and structural details of the major phases depend on the N₂ concentration in the plasma and have significant influence on the Young’s modulus and the elastic recovery of the BC_xN_y thin films.