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

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 lC/cm2. Hf0.5Zr0.5O2 capacitors at an operating voltage of 4V 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.Financial support from the Spanish Ministry of Economy, Competitiveness and Universities, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (No. SEV-2015-0496) and the MAT2017-85232-R (AEI/FEDER, EU) and MAT2015-73839-JIN projects and from Generalitat de Catalunya (2017 SGR 1377) is acknowledged. I.F. acknowledges Ramón y Cajal Contract No. RYC-2017-22531. J.L. is financially supported by the China Scholarship Council (CSC) with No. 201506080019. S.E. acknowledges the Spanish Ministry of Economy, Competitiveness and Universities for his Ph.D. Contract (No. SEV-2015-0496-16-3) and its cofunding by the ESF. The work of J.L. and S.E. has been done as a part of their Ph.D. program in Materials Science at Universitat Autònoma de Barcelona. INL authors acknowledge the financial support from the European Commission through the Project TIPS (No. H2020-ICT-02-2014-1-644453) and from the French national research agency (ANR) through the projects DIAMWAFEL (No. ANR-15-CE08-0034), LILIT (No. ANR-16-CE24-0022), and MITO (No. ANR-17-CE05-0018). They are also grateful to the joint laboratory INL-RIBER and P. Regreny, C. Botella, and J. B. Goure for the MBE technical support on the Nanolyon technological platform.Peer reviewe