Embodiments of the semiconductor processing methods to form low-κ films on semiconductor substrates are described. The processing methods may include flowing deposition precursors into a substrate processing region of a semiconductor processing chamber. The deposition precursors may include a silicon-containing precursor that has at least one vinyl group. The methods may further include generating a deposition plasma in the substrate processing region from the deposition precursors. A silicon-and-carbon-containing material, characterized by a dielectric constant (κ value) less than or about 3.0, may be deposited on the substrate from plasma effluents of the deposition plasma.