SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 40: Poster Session III: Poster to Mini-Symposium: Infrared nano-optics I

O 40.6: Poster

Dienstag, 2. März 2021, 10:30–12:30, P

Near-field optical investigations of the switching behavior of Ta₂O₅-based ReRAMs — •Christoph M. Bauerschmidt¹, Konstantin G. Wirth¹, Thomas Heisig², Sophia Wahl¹, Andreas Hessler¹, Regina Dittmann², and Thomas Taubner¹ — ¹Institute of Physics (IA), RWTH Aachen — ²Peter Grünberg Institute, Research Center Jülich

Tantalum oxide (Ta₂O₅) shows promising properties for applications as non-volatile Resistive Random Access Memories (ReRAMs). Local resistive switching through a valence change mechanism[1] leads to the formation of reduced Ta₂O_x-filaments of ≈10-100nm in size, accompanied by a difference in conductivity to pristine Ta₂O₅ by seven orders of magnitude[2]. The different stoichiometry and the increase in charge carrier density of Ta₂O_x cause changes of the dielectric function. Our calculations suggest that this change in the dielectric function of the switched Ta₂O_x will lead to a strong near-field contrast in the infrared region. Therefore, scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is performed during this work to investigate these local optical properties with nm-sized spatial resolution. s-SNOM allows us to characterise single switched Ta₂O_x-filaments in Ta₂O₅-films. Furthermore, s-SNOM yields promising opportunities for in-situ investigations of switched filaments through transparent graphene electrodes.
[1] Waser et al., Adv. Mat., 21, 2632-2663 (2009)
[2] Dittmann et al., Adv. Func. Mat., 25, 7154-7162 (2015)