Ferroelectric La‐Doped ZrO2/HfxZr1−xO2 Bilayer Stacks with Enhanced Endurance. Issue 5 (26th February 2021)

• Record Type: Journal Article
• Authors: Popovici, Mihaela; Walke, Amey M.; Banerjee, Kaustuv; Ronchi, Nicolo; Meersschaut, Johan; Celano, Umberto; McMitchell, Sean; Spampinato, Valentina; Franquet, Alexis; Favia, Paola; Swerts, Johan; Van den Bosch, Geert; Van Houdt, Jan
• Is Part Of: Physica status solidi. Volume 15:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-26
• Subjects: endurance -- ferroelectric random-access memory -- ferroelectricity -- hafnium zirconate -- lanthanum -- polarization -- ZrO2; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202100033
• Languages: English
• ISSNs: 1862-6254

Abstract

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 ZrO2 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 ZrO2 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 2 P r in the pristine state compared with a stoichiometric HZO doped with the same amount of La 3+ . Both ZrO2 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. Abstract : Enhanced endurance (10 10 cycles) of Hf‐rich hafnium zirconate using 1.6% La dopant is reported. Faster wake‐up behavior is promoted by stacking the ferroelectric layer with ZrO2 . A correlation of ferroelectric characteristics (remanent polarization and endurance) with the initial content of the phase extracted by Rietveld refinement of the X‐ray diffraction spectra brings new insights into modalities to control the ferroelectric behavior of 10 nm hafnium zirconate films grown by atomic layer deposition, with potential application in ferroelectric random‐access memory.