Zr-N diffusion barriers were deposited on the Si substrates by rf reactive magnetron sputtering under various substrate bias voltages. Cu films were subsequently sputtered onto the Zr-N films by dc pulse magnetron sputtering without breaking vacuum. The Cu/Zr-N/Si specimens were then annealed up to 650 degrees C in N-2 ambient for an hour. The effects of deposition bias on growth rate, film resistivity, microstructure, and diffusion barrier properties of Zr-N films were investigated. An increase in negative substrate bias resulted in a decrease in deposition rate together with a decrease in resistivity. It was found that the sheet resistances of Cu/Zr-N(-200 V)/Si contact system were lower than those of Cu/Zr-N(-50 V)/Si specimens after annealing at 650 degrees C. Cu/Zr-N(-200 V)/Si contact systems showed better thermal stability so that the Cu3Si phase could not be detected. (c) 2007 Elsevier B.V. All rights reserved.