Role of the Electrode Material on the RESET Limitation in Oxide ReRAM Devices

Metal‐oxide‐based bipolar resistive switching (BRS) redox‐based resistive switching memory (ReRAM) shows many outstanding properties making it of interest as an emerging nonvolatile memory. However, it often suffers from a low ROFF/RON ratio, while a large ratio is desired to compensate for read mar...

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Bibliographic Details
Published in:Advanced electronic materials 2018-02, Vol.4 (2), p.n/a
Main Authors: Schönhals, Alexander, Rosário, Carlos M. M., Hoffmann‐Eifert, Susanne, Waser, Rainer, Menzel, Stephan, Wouters, Dirk J.
Format: Article
Language:English
Subjects:
oxygen exchange
ReRAM
RESET
retention
tantalum oxide
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Summary:Metal‐oxide‐based bipolar resistive switching (BRS) redox‐based resistive switching memory (ReRAM) shows many outstanding properties making it of interest as an emerging nonvolatile memory. However, it often suffers from a low ROFF/RON ratio, while a large ratio is desired to compensate for read margin loss due to the intrinsic variability of the ReRAM cells. Understanding of the physical processes responsible for limitations of the ROFF and RON in ReRAM cells is therefore of high importance. In this paper a study on the RESET process in BRS Ta2O5‐based ReRAM cells is presented. The ROFF is found to be limited by a secondary volatile resistive switching mode that shows an opposite polarity compared to the main BRS mode. Based on results of switching kinetics measurements a physical model is proposed. It involves an oxygen exchange reaction at the metal‐oxide/active electrode interface combined with a drift‐diffusion induced migration of the resulting oxygen vacancy defects within the metal‐oxide. Incorporation of a thin oxygen‐blocking layer at the active interface allows for a suppression of the secondary switching mechanism. The improved RESET characteristic results in a strongly increased maximum ROFF. These results provide new insights into the role of the electrode material on the RESET process in BRS ReRAM cells. A resistive switching (RS) study in Ta2O5‐based ReRAM cells reveals a limitation of the RESET process, caused by a volatile RS mode concomitant to the main RS mode with opposite polarity. A physical explanation of this additional RS mode is proposed. The role of the active electrode material is investigated revealing its strong impact on the RS characteristics.
ISSN:2199-160X
2199-160X
DOI:10.1002/aelm.201700243