Effect of nitrogen incorporation on improvement of leakage properties in high-k HfO2 capacitors treated by N2-plasma

Abstract
The nitrogen incorporation into the HfO2 films with an EOT (equivalent oxide thickness) of 9Å was performed by N2-plasma to improve the electrical properties. The dielectric properties and a leakage current characteristics of the capacitors were investigated as a function of plasma power and plasma treatment temperature. The dielectric constant of the capacitors is not influenced by nitrogen incorporation. The N2-plasma treatment at 300°C and 70W exhibits the most effective influence on improvement of the leakage current characteristics. Leakage current density of the capacitors treated at 300°C and 70W exhibits a half order of magnitude lower than that without plasma treatment. Nitrogen incorporated into the HfO2 films possesses the intrinsic effect that drastically reduce the electron leakage current through HfO2 dielectrics by deactivating the VO (oxygen vacancy) related gap states.