The effect of carrier gas and H(hfac) on MOCVD Cu films using (hfac)Cu(1,5-COD) as a precursor

Abstract

The deposition characteristics of metalorganic chemical vapor deposition (MOCVD) Cu using (hfac)Cu(1,5-COD)(1,1,1,5,5,5-hexafluro-2,4pentadinato Cu(I) 1,5-cyclooctadiene) as a precursor have been investigated in terms of carrier gas effects and adding H(hfac) to the carrier gas stream. Using hydrogen carrier gas led to a higher MOCVD Cu deposition rate and a lower film resistivity compared to an argon carrier gas system. Improvements in surface roughness of the MOCVD Cu films and a (111) preferred orientation texture were obtained by using hydrogen as a carrier gas. When a ligand such as H(hfac) was added to Ar carrier gas, the deposition rate was significantly enhanced. Moreover, H(hfac) added to both carrier gas streams led, to lower MOCVD Cu film resistivity. However, film adhesion was somewhat weak compared to that observed with the Ar or H2 carrier gas system, probably due to the larger F content near the interface between the copper and the titanium-nitride film. In conclusion, smooth Cu films with a low resistivity can be obtained by manipulating the deposition conditions, such as carrier gas type and ligand addition. The deposition mechanism of MOCVD Cu is also discussed in the paper.