The incorporation of copper in CVD aluminum by diffusion from in-situ sputtered sources

It is demonstrated that in-situ sputtered Cu-containing films serve as excellent diffusion sources for chemical vapor deposited (CVD) Al at temperatures as low as 230°C. Pure Cu, Al-2 wt.% Cu, and Al-0.5 wt.% Cu were used as the source film. Rutherford backscattering spectroscopy (RBS) was used to determine the film grain structures. It was found that the diffusion of Cu from the in-situ Cu-Al film is unhindered by the CVD process and reaches a concentration approximately that of the solid solubility in the CVD Al. A maximum of 0.37 wt.% of the Cu is incorporated into the CVD film from a sputtered pure Cu source. This should provide adequate electromigration resistance for the CVD Al