(Invited) Dielectric Properties and Flat-Band Voltages of Doped- HfO 2 Thin Films

The control of high-symmetry phases of HfO2 can be achieved by cationic substitution for Hf. The electrical properties of the cubic HfO2 phase stabilized by addition of yttrium or magnesium were investigated. The introduction of moderate Y or Mg doping content (~10-15%) in HfO2 results in an enhancement of the dielectric constant. No degradation of the interface state density and of the leakage current was noticed. The flat-band voltage is shifted to positive voltages, similarly as it was observed for monoclinic and cubic pure HfO2 thin films. This result confirms that the contribution of the SiO2/high-k interface to the flat-band voltage depends on the structural interface properties.