Effects of nitrogen fraction on the structure of amorphous silicon-carbon-nitrogen alloys

The silicon-carbon-nitrogen (SiCN) alloys prepared by DC magnetron sputtering at room temperature with graphite and silicon targets at different nitrogen partial pressure were systematically investigated. It was found that a high nitrogen fraction in the nitrogen-argon gaseous mixture enhances the incorporation of C and N, but reduces the incorporation of Si. The Si-C, Si-N, Si-Si, C-N, C double bond N, C triple bond N, C-O, C-C, C double bond C and N-H bonds can all be observed in the alloys. The C-N, C double bond C and C double bond N bonds dominate the structure of the alloys, while the Si-C, Si-Si and Si-N bonds are less significant. As the N₂/(N₂+Ar) ratio increases, the densities of the Si-C, Si-N and C-N bonds decrease, while those of the C double bond N, C-C, C double bond C and C triple bond N bonds increase. In addition, the deposition rate is found to monotonically increase with the nitrogen partial pressure, probably due to the enhanced incorporation of nitrogen and carbon.