A method for depositing a low dielectric constant film is provided. The low dielectric
constant film includes alternating sublayers, which include at least one carbon-doped
silicon oxide sublayer. The sublayers are deposited by a plasma process than includes
pulses of RF power. The alternating sublayers are deposited from two or more compounds
that include at least one organosilicon compound. The two or more compounds and
processing conditions are selected such that adjacent sublayers have different
and improved mechanical properties.