Spectra characterization of silicon carbonitride thin films by reactive radio frequency sputtering

Silicon carbonitride thin films were synthesized on single-crystal Si(100) substrates by reactive rf sputtering a SiC target in nitrogen and argon mixture gas (1:4) and a $Si3N4$ target in methane and argon mixture gas (1:5 and 1:8), respectively. The effect of target voltage on chemical composition and bonding configuration of thin films were studied. Auger electron spectra confirmed the presence of Si, C, N, and O elements in the deposited films. With the assumption that the absorption coefficient of each band was constant within the range of the film composition in question, Fourier-transform infrared spectra measurement showed qualitatively the dependence of the bonding configuration on the plasma energy. X-ray photoelectron spectroscopy analysis showed the formation of a complex network among Si, C, and N elements with more complicated atomic chemical environments than that in a mixture of pure phases, a clear correlation of binding energy and intensity of fitted features of $Si 2p,$ $C 1s,$ $N 1s,$ and $O 1s$ peaks on the target voltage. Spectra analysis reflected that the incorporation of carbon into silicon nitride and the tetrahedral carbon species $(sp3$ including C–C and C–N species) was enhanced by increasing the target voltage. The results demonstrated that the bonding configuration and chemical composition could be tailored by adjusting the plasma energy.