A comparison of structures and properties of SiNx and SiOx films prepared by PECVD

In this paper, amorphous silicon nitride (SiNx) and silicon oxide (SiOx) films were prepared by plasma-enhanced chemical vapor deposition (PECVD). The chemical structures and physical properties of the resulting materials were investigated and compared. Results reveal that SiOx films match better with Si substrate, whereas SiNx films exhibit larger refractive index, moderate optical band gap, and higher Youngʹs modulus and film hardness. In overall, SiNx films are more suitable to serve as supporting and insulating materials for VOx-based infrared microbolometers. The difference in the physical properties is attributed to various bonding configurations for the resulting materials. Finally, several methods for evaluating the residual stresses in amorphous thin films were discussed.