Atomic layer deposition of HfNx films and improving the film performance by annealing under NH3 atmosphere

HfNx films were deposited by atomic layer deposition (ALD) using Hf[N(CH3)(C2H5)](4) (TEMAHf) and NH3 as the Hf-precursor and reactant gas, respectively. A precleaning step using TEMAHf as a reducing agent was devised to minimize the oxygen concentration in the as-deposited film. Consequently, the oxygen concentration in the film was reduced by similar to 66%. In addition, the carbon impurity concentration caused by the side effects of the precleaning step and the remaining oxygen concentration were effectively reduced through post-NH3 annealing. The oxygen concentration inside HfNx decreased as the annealing temperature increased. HfNx films annealed under 900 degrees C showed dielectric properties similar to hafnium oxynitride (HfOxNy). However, films annealed over 950 degrees C transformed into a more electrically conducting HfN film, showing a resistivity of similar to 10(6) mu omega cm.