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Role of the Electrode Material on the RESET Limitation in Oxide ReRAM Devices
Author(s) -
Schönhals Alexander,
Rosário Carlos M. M.,
HoffmannEifert Susanne,
Waser Rainer,
Menzel Stephan,
Wouters Dirk J.
Publication year - 2018
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201700243
Subject(s) - resistive random access memory , materials science , reset (finance) , electrode , optoelectronics , oxide , memristor , oxygen , nanotechnology , electronic engineering , chemistry , metallurgy , organic chemistry , financial economics , engineering , economics
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 R OFF / R ON 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 R OFF and R ON in ReRAM cells is therefore of high importance. In this paper a study on the RESET process in BRS Ta 2 O 5 ‐based ReRAM cells is presented. The R OFF 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 R OFF . These results provide new insights into the role of the electrode material on the RESET process in BRS ReRAM cells.