Amorphous carbon nitride films have been deposited by vacuum cathodic arc method at various N-2/Ar flow ratios and substrate temperatures. The properties of the films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (IR) spectroscopy. At 200 and 400 degreesC, the N content could arrive at 16-18 at.% and showed the increasing tendency and then came to the saturation values with the N-2/Ar ratio. While at room temperature it could be up to 31 at.% and the failing stage was even observed after the saturation. At 200 and 400 degreesC, from 0/50 to 50/50 seem, the development of the aromatic cluster component was observed. In addition, there was probably some interlinked carbon backbone component in the films and the N atoms were mainly incorporated into the aromatic clusters. In the range of 150/50-400/50 sccm, it seems that the temperature played the similar role to N-2/Ar ratio in affecting the microstructure. The films developed from polymeric-like type to the type similar to amorphous carbon with the temperature at 150/50 seem and with N-2/Ar ratio at room temperature, respectively. In addition, in the case of 400 degrees C with increasing N-2/Ar flow ratio from 150/50 to 400/50 seem or in another case of 250/50 sccm with increasing the substrate temperature from room temperature (RT) to 400 degreesC, the decreasing of polymeric component and then the development of aromatic component was observed. Furthermore in both cases of 400 degreesC and 400/50 seem, respectively, the aromatic cluster component developed gradually. As for the film at 400/50 seem: 400 degreesC, there was probably some interlinked N-containing backbone component. The chemical sputtering, which increased with the N-2/Ar ratio and substrate temperature, might play an important role in deciding the N content of the films and the transferring of the microstructure. (C) 2003 Elsevier B.V. All rights reserved.