High-Endurance Ferroelectric (La, Y) and (La, Gd) Co-Doped Hafnium Zirconate Grown by Atomic Layer Deposition
M. Popovici, A. Walke, Jasper Bizindavyi, Johan Meersschaut, Kaustuv Banerjee, Goedele Potoms, Kostantine Katcko, G. Van den bosch, Romain Delhougne, Gouri Sankar Kar, Jan Van Houdt
Abstract
Thin films based on stoichiometric hafnium zirconate doped and co-doped with La, Gd, and/or Y have been grown by atomic layer deposition on TiN electrodes. The resulting TiN–ferroelectric–TiN capacitors have shown high endurance up to 1 × 1011 switching cycles. The simultaneous use of two dopants (Y, La) or (Gd, La) in hafnium zirconate increases the amount of orthorhombic and tetragonal phases. Fatigue-free capacitors with remnant polarization ≥15 μC/cm2 at 1 × 1011 endurance cycles have been obtained for dopants having an atomic fraction of about 1.2–1.8% and showing great promise as active materials for emerging memory applications.