Methods of preparing a carbon doped oxide (CDO) layer with a low dielectric constant (<3) and low residual stress without sacrificing important integration properties such as dry etch rate, film stability during wet cleaning, electrical leakage current, and extinction coefficient are provided. The methods involve, for instance, providing a substrate to a deposition chamber and exposing it to a chemical precursor having molecules with at least one carbon-carbon triple bond, 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 compressive stress or a tensile stress of between about -20 to 30 MPa and a dielectric constant of between about 2.5-3.0, a C.ident.C to SiO bond ratio of between about 0.05% to 5%, a SiC to SiO bond ratio of between about 2% to 10%, and a refractive index (RI) of 1.39-1.52 measured at 633 nm.