Abstract
A tetragonal HfO 2 (t-HfO 2 ) with higher-k value and large band gap is investigated in this work. X-ray diffraction analysis shows a t-HfO 2 can be formed by using Cl 2 plasma treatment at the HfO 2 /Si interface after a post deposition annealing at 650 °C. The mechanisms of t-HfO 2 formation can be attributed to the Si diffusion and oxygen vacancy generation which are formed by Cl 2 plasma treatment. From the cross-sectional transmission electron microscope and capacitance-voltage measurement, the k value of this t-HfO 2 is estimated to be about 35. The optical band gap value for t-HfO 2 is similar to that of the monoclinic. © 2012 American Institute of Physics.