Enhanced ferroelectricity in epitaxial Hf0.5Zr0.5O2 thin films integrated with Si(001) using SrTiO3 templates

Abstract

SrTiO3 templates have been used to integrate epitaxial bilayers of ferroelectric Hf0.5Zr0.5O2 and La2/3Sr1/3MnO3 bottom electrodes on Si(001). The Hf0.5Zr0.5O2 films show enhanced properties in comparison to equivalent films on SrTiO3(001) single crystalline substrates. The films, thinner than 10 nm, have a very high remnant polarization of 34 μC/cm2. Hf0.5Zr0.5O2 capacitors at an operating voltage of 4 V present a long retention time well beyond 10 years and high endurance against fatigue up to 109 cycles. The robust ferroelectric properties displayed by the epitaxial Hf0.5Zr0.5O2 films on Si(001) using SrTiO3 templates pave the way for the monolithic integration on silicon of emerging memory devices based on epitaxial HfO2.