Method of forming a contact in a semiconductor device with engineered plasma treatment profile of barrier metal layer

A method of forming a contact in a semiconductor device provides a titanium contact layer in a contact hole and a MOCVD-TiN barrier metal layer on the titanium contact layer. Impurities are removed from the MOCVD-TiN barrier metal layer by a plasma treatment in a nitrogen-hydrogen plasma. The time period for plasma treating the titanium nitride layer is controlled so that penetration of nitrogen into the underlying titanium contact layer is substantially prevented, preserving the titanium contact layer for subsequently forming a titanium silicide at the bottom of the contact.