The diffusion barrier's performance of Zr-Si film in Cu/Si contacts has been investigated. Cu/Zr-Si/Si contact system was deposited by using radio frequency reactive sputtering technique. Annealing studies for Cu/Zr-Si/Si were then carried out in nitrogen to investigate Cu diffusion and barrier film crystallization. The contact system was characterized by using four-point probe sheet resistance measurements, X-ray diffraction, scanning electron microscope, and Auger electron spectroscopy (AES), respectively. It is observed that the sheet resistance of Cu/Zr-Si/Si contact system is lower than that of as-deposited specimens even after annealing at 700 degrees C. The Cu/Zr-Si/Si contacts tolerated annealing at 800 degrees C for an hour without structural change of the barrier. AES depth profiles of the annealed Cu/Zr-Si/Si samples are similar to each other and have no intermixing evidence. Zr-Si was found to be a promising diffusion barrier material for Cu metallization. (C) 2007 The Electrochemical Society.