Abstract: Embodiments of the present invention provide methods of forming and densifying a titanium nitride barrier layer. The densification process is performed at a relatively low RF plasma power and high nitrogen to hydrogen ratio so as to provide a substantially titanium rich titanium nitride barrier layer. In one embodiment, a method for forming a titanium nitride barrier layer on a substrate includes depositing a titanium nitride layer on the substrate by a metal-organic chemical vapor deposition process, and performing a plasma treatment process on the deposited titanium nitride layer, wherein the plasma treatment process operates to densify the deposited titanium nitride layer, resulting in a densified titanium nitride layer, wherein the plasma treatment process further comprises supplying a plasma gas mixture containing a nitrogen gas to hydrogen gas ratio between about 20:1 and about 3:1, and applying less than about 500 Watts RF power to the plasma gas mixture.