Diffusion barrier properties of TaNx films prepared by plasma enhanced atomic layer deposition from PDMAT with N2 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 N2 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 N2 plasma. The thermal stability of the TaNx films could be improved by reducing the pressure of the reactants and by increasing the plasma exposure time. The TaNx films deposited using N2 plasma exhibit better diffusion barrier properties than the films deposited using NH3 plasma.