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Silicon carbon nitride thin films are deposited by sputtering a silicon carbide target under mixed Ar–N2 atmosphere. The flow ratio (RF = [N2]/[N2] + [Ar]) of these two gazes is set between 0 and 1. The deposits were analyzed by Rutherford backscattering (RBS), infrared, Raman, and electron spin resonance (ESR) spectroscopies. Nitrogen content in thin film was found to be sensitive to the sputtering atmosphere until RF = 0.3 and reached a plateau between 0.3 and 1. From a structural point of view, the analysis revealed that the sp2 carbon character and the C≡N or CN bonds increased with the nitrogen percentage in the gas mixture. These effects induced an increase of the structural disorder and the amount of dangling bonds in the layer bulk. The optical properties in terms of optical gap (Eg) and Urbach parameter (Eu) were also determined. Eg was found to increase with nitrogen percentage in the sputtering mixture, whereas Eu exhibited an opposite behavior. We also show that the refractive index and the extinction coefficient determined by ellipsometric spectroscopy are sensitive to the structural modification.

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