Raman Study of Ring Structures of Chemical Vapor Deposited SiO2 Thin Films.

Raman spectroscopy was applied to the analysis of SiO2 thin films formed by various chemical vapor deposition (CVD) methods. Different sizes of siloxane ring structure were successfully detected in the CVD films. The intensity of the Raman scattering band attributable to the three-membered ring (R3) was found to be a characteristic feature of the film. The deposition method as well as its conditions apparently affected the ratio of the intensity of the R3 band to that of the R4 band. From consideration of the etching rate measurement, it is suggested that the R3 structure can be regarded as a kind of defect of the siloxane network. The constitution of the ring structures given by the Raman spectroscopy is probably a useful indicator of the properties of CVD SiO2 dielectric films.