The investigation of carbon nitride films deposited at various substrate temperatures and N2/Ar flow ratios by vacuum cathodic arc method

Abstract

Amorphous carbon nitride films have been deposited by vacuum cathodic arc method at various N2/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°C, the N content could arrive at 16–18at.% and showed the increasing tendency and then came to the saturation values with the N2/Ar ratio. While at room temperature it could be up to 31at.% and the falling stage was even observed after the saturation. At 200 and 400°C, from 0/50 to 50/50sccm, 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 150/50–400/50sccm, it seems that the temperature played the similar role to N2/Ar ratio in affecting the microstructure. The films developed from polymeric-like type to the type similar to amorphous carbon with the temperature at 150/50sccm and with N2/Ar ratio at room temperature, respectively. In addition, in the case of 400°C with increasing N2/Ar flow ratio from 150/50 to 400/50sccm or in another case of 250/50sccm with increasing the substrate temperature from room temperature (RT) to 400°C, the decreasing of polymeric component and then the development of aromatic component was observed. Furthermore in both cases of 400°C and 400/50sccm, respectively, the aromatic cluster component developed gradually. As for the film at 400/50sccm: 400°C, there was probably some interlinked N-containing backbone component. The chemical sputtering, which increased with the N2/Ar ratio and substrate temperature, might play an important role in deciding the N content of the films and the transferring of the microstructure.