The tungsten piperidylhydrazido complex Cl-4(CH3CN) W(N-pip) (1) was used as a single-source precursor for film growth of tungsten carbonitride (WNxCy) by metal-organic chemical vapor deposition (CVD) in H-2 carrier. Multiple spectroscopic techniques were used for preliminary evaluation of the suitability of 1 as a precursor and to suggest possible fragmentation pathways. The microstructure of films deposited below 500 degrees C was X-ray amorphous, with the highest N content in the film occurring for growth at 400 degrees C. The chemical bonding state of films deposited at 400 degrees C was WNxCy, while tungsten oxide (WO3) was observed for films deposited at 300 degrees C. Film growth rates varied from 2.7 angstrom/min (300 degrees C) to 29.4 angstrom /min (700 degrees C) with deposition temperature. The lowest measured resistivity value is 0.9 m Omega cm for a film grown at 550 degrees C. The diffusion barrier properties were investigated using Cu/WNxCy/Si stacks consisting of Cu deposited by reactive sputtering on WNxCy films deposited at 400 degrees C. The Cu/WNxCy/Si stacks annealed at 500 degrees C for 30 min maintained the integrity of both Cu/WNxCy and WNxCy/Si interfaces as determined by x-ray diffraction measurement, detection of etch-pits, and the Auger electron spectroscopy depth profile. These results support the conclusion that WNxCy deposited from 1 is a viable barrier material to prevent diffusion of Cu in Si for Cu interconnect technology. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3561669] All rights reserved.