Structure and thermal behavior of N containing a-C films obtained by high energy ion beam deposition

a-C:N films have been obtained by high energy ion beam deposition at ambient temperature, using CH4–N2 and CH4–NH3as starting gas mixtures. The as-deposited and thermally annealed samples were studied using APS, Raman, KVV Auger and EELS spectroscopies. The experimental results indicate that the sp2 bonded C content is about 60% and that there is a reduced short range order in the a-C:N films as compared with a-C ones. Thermal graphitization is dependent on the thickness and chemical composition of the films; it is suggested that the size of the graphitic clusters is smaller in annealed a-C:N samples than in annealed N free films. For N containing films thicker than about 300 nm, Raman spectra and electrical conductivity show that graphitization occurs at about 4008C; for films with a thickness lower than 150 nm graphitization occurs at around 7008C. q1997 Elsevier Science B.V.