| AVS 64th International Symposium & Exhibition | |
| Novel Trends in Synchrotron and FEL-Based Analysis Focus Topic | Tuesday Sessions |
| Session SA+AS+HC+SS-TuA |
| Session: | Frontiers of Photoelectron Spectroscopy: Surface & Interface Processes with Variable Depth Probe, High Spatial or Temporal Resolution |
| Presenter: | Munique Kazar Mendes, CEA/LETI-University Grenoble Alpes, France |
| Authors: | M. Kazar Mendes, CEA/LETI-University Grenoble Alpes, France E. Martinez, CEA/LETI-University Grenoble Alpes, France O.J. Renault, CEA/LETI-University Grenoble Alpes, France R. Gassilloud, CEA/LETI-University Grenoble Alpes, France M. Bernard, CEA/LETI-University Grenoble Alpes, France M. Veillerot, CEA/LETI-University Grenoble Alpes, France J.M. Ablett, Synchrotron SOLEIL, France N. Barrett, SPEC, CEA Saclay - University Paris-Saclay, France |
| Correspondent: | Click to Email |
Conductive bridging random access memories (CBRAM) are emerging devices for the next generation of non-volatile memories (NVM) (1). The CBRAM mechanism is related to ionic transport and electrochemical reactions, which give rise to the formation and dissolution of a conductive filament through the insulating dielectric layer (2). Data storage relies on switching the resistivity between two high (HRS) and low (LRS) resistance states by applying voltage or current pulses. We investigate the electrochemical reactions involved in the switching mechanism of Al2O3-based CBRAMs with different active electrodes (TiTe and ZrTe) (3). We have used hard X-ray photoelectron spectroscopy to learn about electrochemical reactions involved in the switching mechanism with sufficient depth sensitivity. Photon energies of 6.9, 8.0 and 10.0 keV were chosen to obtain a non-destructive in-depth chemical characterization with varying sampling depths. The HAXPES experiments were performed at the Galaxies beamline (Soleil) on As-grown samples, after ex-situ forming (Formed) and after Reset operations. The comparison between these different resistance states shows the role and evolution of the electrode/electrolyte interfaces during electrical biasing. For the TaN/TiTe/Al2O3/Ta stack, results highlight, the reduction of Ti together with alumina oxidation after forming. The sample polarization causes oxygen migration, probably in the O2- form, pushed by the upper negative bias towards the interface between the active electrode and the solid electrolyte (Al2O3). When reversing the polarity of the applied voltage (Reset operation), we observe Ti reoxidation and alumina reduction, characterizing oxygen migration towards the active TiTe electrode. These results reveal the important role of oxygen migration in the filament formation/dissolution. ToF-SIMS measurements are also performed to get complementary in-depth chemical information. We will finally compare the two active electrodes to investigate the influence of the composition on the switching mechanism.
References
1. Kozicki MN, Barnaby HJ. Conductive bridging random access memory—materials, devices and applications. Semicond Sci Technol. 2016;31(11):113001.
2. Waser R, Dittmann R, Staikov G, Szot K. Redox-Based Resistive Switching Memories - Nanoionic Mechanisms, Prospects, and Challenges. Adv Mater. 2009 Jul 13;21(25-26):2632–63.
3. Jameson JR, Kamalanathan D. Subquantum conductive-bridge memory. Appl Phys Lett. 2016 Feb 1;108(5):053505.