A process is provided for depositing an silicon oxide film on a substrate disposed in a process chamber. A process gas that includes a halogen source, a fluent gas, a silicon source, and an oxidizing gas reactant is flowed into the process chamber. A plasma having an ion density of at least 10.sup.11 ions/cm.sup.3 is formed from the process gas. The silicon oxide film is deposited over the substrate with a halogen concentration less than 1.0%. The silicon oxide film is deposited with the plasma using a process that has simultaneous deposition and sputtering components. The flow rate of the halogen source to the process chamber to the flow rate of the silicon source to the process chamber is substantially between 0.5 and 3.0.