Ferroelectric yttrium doped hafnium oxide films from all-inorganic aqueous precursor solution

We report a unique aqueous solution deposition method to prepare yttrium doped hafnium oxide (Y:HfO2) thin films using all-inorganic reagents. The composition and chemical bonding features of the films were investigated using X-ray photoelectron spectroscopy. The Y:HfO2 film was integrated into metal-insulator-semiconductor (MIS) structure capacitors for electrical measurements. A transition of the polarization behavior from apparent ferroelectric-type to linear dielectric-type was observed for films with thickness increasing from 25 nm to 80 nm, which is correlated to the dominant crystal structure change from high-symmetry phase to monoclinic phase evidenced by grazing incidence X-ray diffraction analysis.