Structural characterization of nitrogen doped diamond-like carbon films deposited by arc ion plating

Nitrogen doped diamond-like carbon films were deposited on Si (1 0 0) substrates by arc ion plating (AIP) technique under different N2 volume percentage in the gas mixture of Ar and N2. The deposited films were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Raman spectra indicate that the ID/IG ratio increases with increasing the N2 volume percentage. XPS analysis shows a strong influence of the N2 volume percentage on the N atom concentration and the chemical bonding states in the deposited films. Nitrogen content of the deposited films increased with the increasing of N2 volume percentage. The maximum N concentration and N/C atomic ratio are up to 12.7 at.% and 0.162 at the 90 vol.% N2, respectively. From decomposition of XPS C 1s peaks, it shows that the nitrogen doped diamond-like carbon films consist of amorphous carbon–carbon bonding (sp2C–C and sp3C–C), N atoms bonded to sp3-hybridized C atoms (sp3C–N) and N atoms bonded to sp2-hybridized C atoms (sp2C–N). The total content of sp3 bonding decreases with increasing N2 volume percentage. XPS N 1s spectra show that there exist the N–sp2C and N–sp3C bonding in the deposited nitrogen doped diamond-like carbon films. As the N2 volume percentage increases, the N–sp3C bonding content increases, but the N–sp2C bonding content decreases.