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

Abstract

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.