SKM 2023 – scientific programme
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DS: Fachverband Dünne Schichten
DS 12: Poster
DS 12.5: Poster
Wednesday, March 29, 2023, 17:00–19:00, P3
From Doping to Dilution: Local Chemistry and Collective Interactions of La in HfO2 — •Oliver Rehm1, Thomas Szyjka1,2, Lutz Baumgarten2, Claudia Richter3, Yury Matveyev4, Christoph Schlueter4, Thomas Mikolajick3,5, Uwe Schroeder3, and Martina Müller1 — 1Uni Konstanz, Konstanz, Germany — 2FZJ, Jülich, Germany — 3NaMLab, Dresden, Germany — 4DESY, Hamburg, Germany — 5TU Dresden, Dresden, Germany
HfO2-based thin films exhibit huge potential for the next generation of nonvolatile memory applications, such as FeRAM or FeFET. The application of HfO2-based thin films as active ferroelectrics (FE) in these devices face reliability issues like wake-up, imprint, and fatigue. The FE phase of HfO2 is the metastable orthorhombic structure, for which La doping is considered a promising route for stabilization.
La:HfO2 samples were grown by ALD with a range of La doping, from 3.5% to 33%, i.e., from the doping to dilution level. We link the local chemistry at the La lattice sites with local and collective electronic properties of the La:HfO2 matrix using HAXPES. The satellite structure of La 3d core level, the plasmonic excitation energies, and core-level rigid binding energy (BE) shifts are investigated. The emerging chemical phases and electronic properties are discussed as a function of La doping. From the evolution of the plasmon excitation energies and rigid BE shifts, it is concluded that electronic charge compensation by oxygen vacancies occurs for increasing La content.
[1] T. Szyjka, et al., Phys. Status Solidi RRL 2022, 16, 2100582