Atomic rearrangement of sputtered amorphous carbon nitride thin films during growth

Abstract Spectroscopic investigations of amorphous carbon nitride thin films (a-CN x ) deposited by radio-frequency (RF) magnetron sputtering on (100) silicon wafers, under different RF power, are reported. The local bonding in the a-CN x films was analyzed by Fourier Transform Infrared (FTIR) and Raman spectroscopies correlated with Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA) measurements. The refractive index was determined using optical transmission spectroscopy. The microstructure analysis revealed the porous character of films and their post deposition contamination by oxygen and water, which decreases slowly with increasing RF power. Its correlation with the mass density and the refractive index leads to introduce the surface/volume ratio of the porosities as the determinant microstructural parameter to interpret the changes in the infrared (IR) absorption spectra as the RF power increases.