Electrical characteristics and reliability of hafnium oxide films with nitrogen doping

The effects of trace amount of nitrogen doping on the electrical characteristics of thin hafnium oxide have been studied. The chemical compositions and bonding structure of the dielectric film have been explored with x-ray photoelectron spectroscopy (XPS) measurements. Current-voltage (I-V) and capacitance-voltage (C-V) measurements have been conducted on nitrogen-doped hafnium oxide samples and to study the reliability of the film constant-voltage stressing has been performed. The trapping characteristics have been further revealed by conducting the I-V and C-V measurements at different temperatures ranging from 100 to 400 K. We have found that although the deep trap level due to oxygen vacancy and interface trap density due to Hf-Si bonding can be significantly suppressed with nitrogen doping; large amount of shallow traps are still present.