Exemplary semiconductor processing methods may include providing deposition precursors to a processing region of a semiconductor processing chamber. The deposition precursors may include a silicon-oxygen-and-carbon-containing precursor. A substrate may be disposed within the processing region. The methods may include forming plasma effluents of the deposition precursors. The methods may include depositing a layer of silicon-oxygen—and—carbon-containing material on the substrate. The layer of silicon-oxygen—and—carbon-containing material may be characterized by a dielectric constant of less than or about 4.5. The layer of silicon-oxygen—and—carbon-containing material may be characterized by a density of greater than or about 2.0 g/cm3.