Abstract: Methods of preparing a carbon doped oxide (CDO) layer with a low dielectric constant (<3.2) and low residual stress without sacrificing important integration properties such as refractive index and etch rate are provided. The methods involve, for instance, providing a substrate to a deposition chamber and exposing it to TMSA, followed by igniting and maintaining a plasma in a deposition chamber using radio frequency power having high and low frequency components or one frequency component only, and depositing the carbon doped oxide film under conditions in which the resulting dielectric layer has a net tensile stress of less than about 40 MPa, a hardness of at least about 1 GPa, and a SiC:SiOx bond ratio of not greater than about 0.75.