Tantalum carbonitride thin films were deposited by plasma-enhanced atomic layer deposition using the metallorganic precursor tert-butylimido tris (diethylamido) tantalum and hydrogen/argon direct plasma with 600 W radio frequency power. Within the atomic layer deposition temperature window, which ranges from below 200 to 260 degrees C, films grow with similar to 0.35 angstrom/cycle. At a substrate temperature of 250 degrees C, the process yields Ta2CN films with an oxygen impurity content of below 5 atom %. These films have a cubic nanocrystalline structure, a high density of 13-14 g/cm(3), as well as an excellent low resistivity of 160 mu Omega cm. Furthermore, the films show copper diffusion barrier performance comparable to stoichiometric physical vapor deposition TaN and a feasible wetting on multiwall carbon nanotubes. The interface between the tantalum carbonitride film and the silicon substrate was investigated using analytical electron microscopy and shows nitrogen and carbon agglomeration. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3205457] All rights reserved.