We have investigated impacts of nitrogen incorporation into HfAlOx films on the gate leakage currents and the flat band voltage V-FB shifts. Also, a role of O-Hf-N bonding states in HfAlOx(N) in suppression of boron penetration is discussed. The nitrogen concentration C-N in HfAlOx(N) was controlled by changing the NH3 annealing temperature at the step of the layer-by-layer deposition and annealing process as well as the O2 annealing temperature of post-deposition annealing. The CN over 10 at. % in HfAlOx(N) films effectively suppressed boron penetration as revealed by very slow diffusion in Hf3N4 films and the formation of boron-nitrogen remote complex in HfOx(N), preserved the amorphous structure and reduced the VFB shift compared to the case of HfAlOx without nitrogen incorporation, while CN exceeding 13 at. % led to a significant increase of the gate leakage current. This suggests the excess O-Hf-N bond formation enhanced the leakage current. (C) 2004 American Vacuum Society.