Embodiments include semiconductor processing methods to form low-K films on semiconductor substrates are described. The processing methods may include flowing one or more deposition precursors to a semiconductor processing system, wherein the one or more deposition precursors include a silicon-containing precursor. The silicon-containing precursor may include a carbon chain. The methods may include generating a deposition plasma from the one or more deposition precursors. The methods may include depositing a silicon-and-carbon-containing material on the substrate from plasma effluents of the deposition plasma. The silicon-and-carbon-containing material as-deposited may be characterized by a dielectric constant less than or about 3.0.