Journal Article

FZJ-2018-02368

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Processes and Effects of Oxygen and Moisture in Resistively Switching TaO x and HfO x

Lübben, M. ; Wiefels, S. ; Waser, R.FZJ* ; Valov, I. (Corresponding author)FZJ*

2018
Wiley Chichester

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Please use a persistent id in citations: doi:10.1002/aelm.201700458

Abstract: Foreign components such as dopants and impurities in molecular or ionic form may significantly influence forming/switching processes in redox‐based memories. This work presents a systematic study and discussion on effects of oxygen and moisture in Ta2O5 and HfO2 thin films, being two of the most used materials for redox‐based resistively switching random access memories. Whereas oxygen is found to not affect the device behavior, the presence of moisture profoundly influences it. It plays a crucial role for the counter electrode reaction, providing additional charged species and enabling the formation of oxygen vacancies, thus determining the forming voltage and the kinetics of this process. Here, methods for incorporation of moisture within the oxide films and its defect chemistry are discussed. Based on the standard electrode potentials and analysis of the electrochemical processes at both electrodes, it is possible to predict their sequence during switching. The difference using symmetric cells with inert electrodes Pt/MeOx/Pt and asymmetric devices with ohmic electrodes Me/MeOx/Pt is explained by the electrochemical reaction sequence and ability of the ohmic electrode to undergo redox reactions. Upon oxidation the Me electrode can either exchange O2− with the oxide or can be a source for cations within the MeOx, keeping the balance between oxygen rich/deficient matrix.

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Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 521 - Controlling Electron Charge-Based Phenomena (POF3-521) (POF3-521)

Appears in the scientific report 2018

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Database coverage:
Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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