Deposition of TiN and TaN by remote plasma ALD for Cu and Li diffusion barrier applications

TaN and TiN films were deposited by remote plasma atomic layer deposition (ALD) using the combinations of Ta[N(CH3)2]5 precursor with H2 plasma and TiCl4 precursor with H2–N2 plasma, respectively. Both the TaN and TiN films had a cubic phase composition with a relatively low resistivity (TaN: 380 µ cm; TiN: 150 µ cm). Dissimilar from the TiN properties, the material properties of the TaN films were found to depend strongly on the plasma exposure time. Preliminary tests on planar substrates were carried out revealing the potential of the TaN and TiN films as Cu and Li diffusion barriers in through-silicon via and silicon-integrated thin-film battery applications, respectively. For the specific films studied, it was found that TiN showed better barrier properties than TaN for both application areas. The TiN films were an effective barrier to Cu diffusion and had no Cu diffusion for anneal temperatures up to 700°C. The TiN films showed low Li intercalation during electrochemical charging and discharging