Effect of Annealing Ambience on the Chemical Stability of Zr-Si-N Diffusion Barrier

Zr-Si-N films were deposited by RF magnetron sputtering (MS) technique. A Cu film on the top of Zr-Si-N films was prepared by DC pulsed magnetron sputtering. The Cu/Zr-Si-N systems were annealed in vacuum and N2/H2 gas mixture at 800℃, respectively. The structure of the films were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and four-point probe method. The sheet resistances of the Cu/Zr-Si-N/Si contact systems annealed in N2/H2 gas mixture were lower than those of the specimens annealed in vacuum at 800℃. The residual oxygen contamination from vacuum annealing ambience influences the sheet resistances of the Cu/Zr-Si-N/Si contact systems due to residual oxygen contamination and/or voids in Cu films. Though thermal stabilities of the Cu/Zr-Si-N/Si systems were maintained up to 800℃ when annealed in vacuum and N2/H2 gas mixture, the changes of thermal stability of specimens were noticeable. The vacuum can accelerate the oxidation and decomposition of Zr-Si-N barrier. On the contrary, N2/H2 gas mixture prevent from the Zr-Si-N barrier oxidation and decomposition.