Ta-N-based thin films were deposited by thermal atomic layer deposition. In this work, we introduced a tantalum source. The alternate supply of this halide but liquid precursor tantalum pentachloride, diethyl sulfide (TPDS), and ammonia (NH3) resulted in Ta-N-based films with a saturated growth rate of approximately 0.2-0.3 angstrom/cycle at 300-400 degrees C and less than 1 atom % chlorine. By pulsing trimethylaluminium (TMA) as an additional reacting agent between the TPDS and NH3, the resistivity was improved up to 10(3) mu Omega cm. These films showed a chlorine content of 10 atom % and an aluminum content of less than 1 atom %. X-ray photoelectron spectroscopy, X-ray diffraction, and a standard four-point probe method indicated a shift from tantalum nitride to tantalum-carbonitride-based films with increasing TMA and decreasing NH3 pulse numbers. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3353230] All rights reserved.