Ferroelectric La-Doped ZrO2/HfxZr1-xO2 Bilayer Stacks with Enhanced Endurance

Mihaela Popovici*, Amey M. Walke, Kaustuv Banerjee, Nicolo Ronchi, Johan Meersschaut, Umberto Celano, Sean McMitchell, Valentina Spampinato, Alexis Franquet, Paola Favia, Johan Swerts, Geert Van Den Bosch, Jan Van Houdt

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Hafnium zirconate (HZO) is investigated in metal–ferroelectric–metal capacitors as a function of Hf/(Hf+Zr) atomic ratio, the presence of a thin ZrO 2 seed layer, and/or by doping HZO with La 3+. It is demonstrated that a longer endurance is achieved with Hf-rich HZO by introducing a ZrO 2 seed layer. The endurance is further improved by introducing La 3+ in the Hf-rich HZO layer of the bilayer stack, which offers a higher 2P r in the pristine state compared with a stoichiometric HZO doped with the same amount of La 3+. Both ZrO 2 underlayer and La 3+ doping of HZO are shown to play a decisive role in promoting the formation of an orthorhombic and tetragonal phase at the expense of a detrimental monoclinic phase.

Original languageEnglish
Article number2100033
JournalPhysica status solidi. Rapid research letters
Volume15
Issue number5
Early online date13 Feb 2021
DOIs
Publication statusPublished - May 2021

Keywords

  • ZrO
  • endurance
  • ferroelectric random-access memory
  • ferroelectricity
  • hafnium zirconate
  • lanthanum
  • polarization
  • ZrO2

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