Monocliniclike local atomic structure in amorphous ZrO2 thin film

Abstract

The local atomic structure and electronic structure of amorphous ZrO2 (a-ZrO2) thin film were examined using the Zr K- and O K-edge x-ray absorption spectroscopy and x-ray photoelectron spectroscopy. It was found that a monoclinic local structure is stabilized in several nanometers-thick a-ZrO2 films due to the structural disorder. The distinct local structure in a-ZrO2 from the ordinary tetragonal ZrO2 (t-ZrO2) films results in different electronic structure with a decrease in the band gap by 0.5 eV. The reduced band gap and dielectric constant of a-ZrO2 suggest inferior gate leakage current performances compared to the t-ZrO2 films.