A method and system for depositing a film with tunable optical and etch resistant properties on a substrate by plasma-enhanced chemical vapor deposition. A chamber has a plasma source and a substrate holder coupled to a RF source. A substrate is placed on the substrate holder. The TERA layer is deposited on the substrate. The amount of RF power provided by the RF source is selected such that the rate of deposition of at least one portion of the TERA layer is greater than when no RF power is applied the substrate holder.
