S1-H bonding environment in PECVD a-SiOxNy:H thin films

We constructed silicon oxynitride thin films of various compositions by Plasma Enhanced Chemical Vapor Deposition and studied the global structure by infrared absorption. The Si-H band frequency is related to the environment of Si atom. We considered the Si-H band as the sum of several gaussian curves corresponding to the different silicon-centered tetraedra present in the material. The frequency of Si-H bond for each tetrahedron was calculated using Lucovsky linear relations and then the tetrahedra were attributed to gaussians found by decomposition of the band. The results show the presence of tetrahedra with both N and O atoms bound to silicon. These tetrahedra cannot agree with a model of phase separation, however the Random Bonding Model envisages the existence of these environments. So we consider our silicon oxynitride films to be a homogeneous statistical mixture of the various bonds rather than a mixture of phases. Published by Elsevier Science Limited.