Silicon dielectric films such as silicon nitride, oxide and oxynitride films deposited by Plasma Enhanced and Low Pressure Chemical Vapor Deposition (PECVD and LPCVD) processes were analyzed and compared using Fourier Transform Infrared (FTIR), X-ray Photoelectron, Auger, Electron Spin Resonance Spectroscopies and Nuclear Reaction Analysis for hydrogen. The plasma deposited films exhibit a more random structure with less long-range order and contain more hydrogen as compared to those of LPCVD films. However, marked similarities were observed in the bonding and its variation in films deposited by both processes. Analysis data indicates that the silicon oxynitride films (RI-1.75–1.78), deposited by both processes, may be the most stable oxynitride where mixed silicon oxynitride tetrahedral N²-Si-O² bonding structures are most abundant.