NITROGEN EFFECTS ON THE MICROSTRUCTURAL EVOLUTION OF CARBON-FILMS UNDER THERMAL ANNEALING

Nitrogenated C-films (CNx) were prepared either by rf reactive sputter ing of graphite or by N+-implantation with energies of 30-90 keV. The structural evolution of these films under thermal vacuum annealing, at various temperatures was investigated by means of Raman analysis and positron annihilation spectroscopy (PAS). The atomic film composition was determined by Nuclear Reaction Analysis (NRA) and Elastic Recoil D etection (ERD). Nitrogen incorporation in the C films increases their amorphicity and its effect on the void concentration is connected to t he nature of the nitrogenation process. Upon thermal annealing, the CN x film structure degrades more rapidly than do the C films, increasing the disordered graphitic phase content. The structural changes of the C and the CNx films are associated with H and N dynamical behaviour i nduced by annealing.