Issue 29, 2016

Nanoscopic structural rearrangements of the Cu-filament in conductive-bridge memories

Abstract

The electrochemical reactions triggering resistive switching in conductive-bridge resistive random access memory (CBRAM) are spatially confined in few tens of nm3. The formation and dissolution of nanoscopic Cu-filaments rely on the displacement of ions in such confined volume, and it is driven by the electric field induced ion migration and nanoscaled redox reactions. The stochastic nature of these fundamental processes leads to a large variability of the device performance. In this work, a combination of two- and three-dimensional scanning probe microscopy (SPM) techniques are used to study the conductive filament (CF) formation, rupture and its nanoscopic structural rearrangements. The high spatial confinement of our approach enables to locally induce RS in a confined area and image it in 3D. A conical shape of the CF is consistently observed, indicating that the ion migration is the rate limiting step in the filament formation when using high quality dielectrics as switching layers. The sub-10 nm electrical contact size of the AFM tip is used to study the filament's dissolution and detect the hopping conduction of Cu during the CF rupture. We consistently observe a tunnel gap formation associated with the tip-induced filament reset. Finally, aiming to match the fundamental understanding with the integrated device operations, we apply scalpel SPM to failed memory cells and directly observe the appearance of filament multiplicity as a major source of failures and variability in CBRAM.

Graphical abstract: Nanoscopic structural rearrangements of the Cu-filament in conductive-bridge memories

Supplementary files

Article information

Article type
Paper
Submitted
08 ဒီ 2015
Accepted
24 ဇန် 2016
First published
25 ဇန် 2016

Nanoscale, 2016,8, 13915-13923

Nanoscopic structural rearrangements of the Cu-filament in conductive-bridge memories

U. Celano, G. Giammaria, L. Goux, A. Belmonte, M. Jurczak and W. Vandervorst, Nanoscale, 2016, 8, 13915 DOI: 10.1039/C5NR08735J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements