Ti-Si-N thin films were deposited by plasma-enhanced atomic layer deposition from TiCl4, SiH4, and N-2/H-2/Ar plasma at 350 degrees C. For comparison, TiN plasma-enhanced atomic layer deposition (PEALD) was also performed from TiCl4. The effects of growth parameters on film properties were studied. Especially, the changes in sequences of precursor-reactant exposure steps were found to produce large change in the growth rates and Si concentration in the films. The results are discussed based upon the molecule-surface reaction mechanisms. Also, the Cu diffusion barrier properties of the PEALD Ti-Si-N films were investigated. PEALD Ti-Si-N films have shown better diffusion barrier properties than PEALD TiN films and can be a promising candidate for future Cu interconnect technology beyond 65 nm technology node.] (c) 2006 American Vacuum Society.