IR studies of SiCN films deposited by RF sputtering method

Abstract

Silicon carbon nitride (SiCN) films were deposited on Si (1 0 0) substrates by radio-frequency (RF) sputtering method using SiC target as Si, C source and nitrogen as reactant gas. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to investigate the composition and bonding structures of the SiCN films, indicating that the main bonds such as Si–C, Si–N, C N and C N were formed in the deposited SiCN films. Analysis of XPS indicated that the stoichiometry of the SiCN films deposited at 700 °C was close to 3:3:4. The dependence of the formed chemical bonds in the films on substrate temperature, nitrogen fraction and sputtering power has been studied. The analysis suggested that high substrate temperature is not in favor of the nitrogen incorporation into the SiCN films. Secondly, an optimal N 2/(N 2 + Ar) (36 at.%) would improve the nitrogen element incorporation into the SiCN films. On the other hand, under the impact of high sputtering power with the invariable nitrogen fraction, nitrogen molecules were easily decomposed and can be incorporated into the films effectively. Furthermore, atomic force microscopy (AFM) was used to examine the surface structure of the SiCN films.