Investigation of Zr–N thin films for use as diffusion barrier in Cu metallization

Zr–N thin films as a barrier in Cu/Si contact were investigated. The Cu/Zr–N/Si specimens were prepared and annealed at temperatures up to 700 °C in N₂ ambient for an hour. Characterization of phase composition and crystallite structure of the barriers was performed by XRD, the film morphology was examined using atomic force microscopy (AFM), and the composition profiles of the as-deposited and annealed samples of Cu/Zr–N/Si were identified by Auger electron spectroscopy (AES). It is evident that the Zr–N film structure is very sensitive to the deposition conditions. Cu/Zr–N/Si contact systems showed better thermal stability so that the Cu₃Si phase could not be detected. It is indicated from the comparison analysis results that the Zr–N film showed better thermal stability with increasing N₂ flow ratio and/or negative substrate bias.