The effect of nitrogen concentration on the band gap and band offsets of HfOxNy gate dielectrics

The effect of N concentration on the band gap and band offsets of HfO(x)N(y) films has been systematically investigated. It was found that the band gap as well as the band offsets of HfO(x)N(y) films decreased with the increase of N concentration. When the N concentration reached 16.3%, the conduction band offset (Delta E(c)) reduced to be 0.88 eV, which is smaller than the minimal requirement of Delta E(c) values for high-k dielectrics and, thus, leads to unacceptably high leakage currents. Therefore, nitrogen concentration should be carefully controlled to guarantee excellent properties of nitrogen incorporated high-k dielectrics. (C) 2008 American Institute of Physics.