Diffusion barrier properties of TaNx films prepared by plasma enhanced atomic layer deposition from PDMAT with N-2 or NH3 plasma

Carbon free TaNx films were deposited by plasma enhanced atomic layer deposition (PEALD) using a combination of pentakis(dimethylamino)Ta (PDMAT) and either N-2 or NH3 plasma. Good linearity and saturation behavior were observed for the TaNx films grown with NH3 plasma while non-ideal saturation features were observed for the films grown with N-2 plasma. The thermal stability of the TaN, films could be improved by reducing the pressure of the reactants and by increasing the plasma exposure time. The TaNx films deposited using N-2 plasma exhibit better diffusion barrier properties than the films deposited using NH3 plasma.