TaCx films were deposited by plasma-enhanced atomic layer deposition (PEALD) at a wafer temperature of 300 degrees C using a novel nitrogen-free Ta precursor, tris(neopentyl) tantalum dichloride, Ta[CH2C(CH3)(3)](3)Cl-2 and H-2 plasma as the reactant. Self-limiting film growth was observed with both the precursor and reactant pulsing time. Both X-ray diffraction and electron diffraction analysis consistently showed that a cubic TaC phase formed, even though the film was Ta-rich TaCx (C/Ta = similar to 0.36). The film resistivity decreased with increasing H-2 plasma pulsing time from 900 to 375 mu Omega cm. In this study, a performance of TaCx as a diffusion barrier for Cu interconnects was evaluated. The results showed that the structure of Cu (100 nm)/ALD-TaCx (15 nm)/Si was stable after annealing at 650 degrees C for 30 min. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3594747] All rights reserved.