SKM 2023 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 9: Layer Properties I

DS 9.3: Vortrag

Mittwoch, 29. März 2023, 10:15–10:30, SCH A 316

Substoichiometric conducting HfO_x phases as novel type of electrodes with a built-in oxygen vacancy reservoir for RRAM applications — •Philipp Schreyer¹, Nico Kaiser¹, Eszter Piros¹, Tobias Vogel¹, Taewook Kim¹, Despoina Nasiou², Leopoldo Molina-Luna², and Lambert Alff¹ — ¹Advanced Thin Film Technology Division, TU Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt, Germany — ²Advanced Electron Microscopy Division, TU Darmstadt, Darmstadt, Germany

Hafnium oxide is an outstanding candidate as the active material in RRAM due to its performance and proven CMOS compatibility. In previous studies, we have shown that electrically conducting hafnium oxide phases can be stabilized by significant oxygen deficiency [1,2]. While so far only the physical properties of these structures have been investigated, we reproduced the phases in RRAM configuration to investigate the device properties. Resistive switching was found to be absent in all deficient in-vacuo processed samples. They show ohmic conduction, confirming the conducting nature of the substoichiometric phases. However, when exposed to air, a thin oxidized layer forms at the surface which stabilizes reliable resistive switching. Note that the oxidation process is self-limited leading to reproducible oxide thicknesses of a few nm. We suggest that the substoichiometric phases may act as second electrode with an oxygen vacancy reservoir that stabilizes oxygen vacancy filaments in ultrathin layers of near-stoichiometric HfO₂. [1] N. Kaiser et al., ACS Appl. Mater. Interfaces 14, 1290 (2022). [2] N. Kaiser, accepted. ACS Appl. Electron. Mater. (2023).