INCORPORATION OF NITROGEN IN SPUTTERED CARBON-FILMS

The possibility of depositing carbon nitride with a planar magnetron s putter system has been evaluated. The deposition parameters were varie d with the aim of optimising the nitrogen content and the hardness of the films. Both d.c. and r.f. magnetron power sources were used to dep osit films on zirconium, yttria-stabilised zirconia and sapphire subst rates. The films were studied by electron microscopy (SEM and TEM), Ru therford backscattering and electron energy loss spectroscopy (EELS). The hardnesses of the films were measured by both traditional and dept h-sensing methods. Special attention was paid to the nitrogen content of the films, which depended strongly on the sputtering conditions. Fi lms containing up to 58 at.% nitrogen were made, close to the stoichio metry expected for C3N4. However, all the nitrogen-containing films we re amorphous. The films suffered from high deposition stresses, which in combination with high elastic relaxation also complicated the hardn ess measurements. It was found that the fraction of sp(2) hybridisatio n of the carbon increased with nitrogen content and ion bombardment of the films.