Effect of the deposition gas pressure on the structure and mechanical stability of sputtered amorphous carbon nitride films

We present in this study spectroscopic investigations of amorphous carbon nitride thin films (a-CNx) deposited on Si substrate by radio-frequency magnetron sputtering of a graphite target in Ar/N2 gas mixture, under different deposition gas pressure. The properties of films were determined using atomic force microscopy (AFM), Fourier Transform Infrared measurements, transmission spectroscopy and intrinsic stress measurements. A limiting effect of the terminating bonds and their contamination by water has been examined in relation with optoelectronical and mechanical properties of the films. The appearance of the telephone-cord buckling as an interfacial failure mode has been elucidated and the evolution of their morphological characteristics has been studied in relation with the deposition conditions and the resulting microstructure.