| AVS 65th International Symposium & Exhibition | |
| Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic | Wednesday Sessions |
| Session SA+AS+MI-WeA |
| Session: | Hard X-Ray Photoemission for Probing Buried Interfaces |
| Presenter: | Eugénie Martinez, CEA/LETI-University Grenoble Alpes, France |
| Authors: | E. Martinez, CEA/LETI-University Grenoble Alpes, France BM. Meunier, Univ. Grenoble Alpes, CEA, LETI & LMGP, CNRS, France DP. Pla, Univ. Grenoble Alpes, LMGP, CNRS, France RRL. Rodriguez-Lamas, Univ. Grenoble Alpes, LMGP, CNRS France MB. Burriel, Univ. Grenoble Alpes, LMGP, CNRS, France CJ. Jimenez, Univ. Grenoble Alpes, LMGP, CNRS, France JPR. Rueff, Synchrotron SOLEIL, France Y. Yamashita, NIMS, Japan S. Ueda, NIMS, Japan O.J. Renault, CEA/LETI-University Grenoble Alpes, France |
| Correspondent: | Click to Email |
The use of perovskite oxides in resistive random access memories (RRAMs) is considered for the next generation of non-volatile memories (NVMs) [1]. Indeed, their highly tunable ionic and electronic transport properties open new possibilities for multilevel storage capacity. In particular, manganese oxides, such as LaMnO3+d (LMO), are among the most promising candidates [2].The switching mechanism is related to oxygen transport, yielding to the creation and annihilation of oxygen vacancies through the functional layer. However, two main mechanisms based on filaments or 2D interfacial effects must be discriminated to better understand and control the devices properties.
We investigate here the key role of oxygen in the switching mechanism of LMO-based RRAMs using hard X-ray photoelectron spectroscopy (HAXPES). This technique allows learning about electrochemical reactions involved in the structure with sufficient depth sensitivity. Operando HAXPES was performed at Soleil and SPring-8 to investigate in-situ resistive switching. Measurements were done while biasing the memory with opposite polarities, to reach successively low and high resistance states. In particular, a chemical analysis of the interface between the active electrode and the LMO was done after Set and Reset operations.
Results show modifications of the oxygen core level spectra. The peak assigned to interfacial LMO shifts as a function of bias voltage, contrary to the bulk LMO component. These results highlight variations in charges concentration at the electrode/LMO interface, as a result of creation/annihilation of interfacial defects, such as oxygen vacancies. Complementary trends regarding La3d and Mn3s/2p spectra will be discussed in terms of oxidation and reduction phenomena, related to variations of the oxygen content at the electrode/LMO interface.
[1] Jin YL, Jin KJ, Ge C, Lu HB, Yang GZ, Resistive switching phenomena in complex oxide heterostructures, Modern Physics Letters B, 2013;27(29)1330021.
[2] Pan F, Gao S, Chen C, Song C, Zeng F, Recent progress in resistive random access memories: Materials, switching mechanisms and performance, Mater. Sci. Eng. R 2014,83:1-59.