The effect of deposition processing on structural and luminescent properties of a-SiOC:H thin films fabricated by RF-magnetron sputtering

Amorphous silicon oxicarbide thin films (a-SiOC(:H)) were deposited by RF-magnetron sputtering using Si or SiC target in Ar/CH4/O2 flow. Interatomic bonding and light emission properties were analyzed by FTIR in transmission and attenuation total reflection (ATR) mode, Raman scattering and photoluminescence spectroscopy. Comparison of the results obtained by FTIR and ATR allows us to suggest that structural properties of the near-surface region and the bulk of the films are significantly different. The surface layer contains a significant fraction of polymer-like SiOC structural components in the form of Si-O-Si/Si-O-C chains and cages, while bulk of the film is represented by inorganic amorphous SiOx network with amorphous carbon precipitates. Samples with the high fraction of carbon precipitates exhibit white luminescence at room temperature. The origin of strong photoluminescence is discussed.