Characterization and depth profiles measurements of silicon nitride thin films on silicon and molybdenum substrates by Auger electron spectroscopy

Silicon nitride thin films were deposited on Si or Mo substrates using a technique of plasma enhanced chemical vapor deposition (PECVD). Depth profiles measurements were carried out on these Si3N4 layers, as well as on the Si3N4/Mo and Si3N4/Si interlayer by Auger electron spectroscopy, associated with Argon ion sputtering. For the Si3N4 films deposited on Mo substrates a sequence of three distinguishable zones were observed: the Si3N4 layer; an interlayer containing Si-N, Mo-N, and presumably Mo-Si bonds, a diffusion zone of nitrogen into the Mo substrate. On the Si substrate a more usual depth profile was evidenced involving the sequence of the Si3N4 layer, an interlayer zone with the presence of Si-N and Si-Si bonds, and finally the Si substrate.