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Thin-film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity

Published version
Peer-reviewed

Repository DOI


Type

Article

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Authors

Hellenbrand, Markus 
Bakhit, Babak 
Hongyi, Dou 
Xiao, Ming 
Hill, Megan 

Abstract

A design concept of phase-separated amorphous nanocomposite thin films is presented which realizes interfacial resistive switching (RS) in hafnium-oxide-based devices. The films are formed by incorporating an average of 7% Ba into hafnium oxide during pulsed laser deposition at temperatures ≤400 °C. The added Ba prevents the films from crystallizing and leads to ∼20-nm-thin films consisting of an amorphous HfOx host matrix interspersed with ∼2-nmwide, ∼5-to-10-nm-pitch Ba-rich amorphous nanocolumns penetrating ∼2/3 through the films. This restricts the RS to an interfacial Schottky-like energy barrier whose magnitude is tuned by ionic migration under an applied electric field. Resulting devices achieve stable cycle-to-cycle, device-to-device, and sample-to-sample reproducibility with a measured switching endurance of ≥10⁴ cycles for a memory window ≥10 at switching voltages of ±2 V. Each device can be set to multiple intermediate resistance states, which enables synaptic spike-timing-dependent plasticity. The presented concept unlocks additional design variables for RS devices.

Description

Keywords

40 Engineering, 4016 Materials Engineering, 51 Physical Sciences

Journal Title

Science Advances

Conference Name

Journal ISSN

2375-2548
2375-2548

Volume Title

9

Publisher

American Association for the Advancement of Science
Sponsorship
European Commission Horizon 2020 (H2020) ERC (882929)
Cambridge Herchel Smith postdoctoral fellowship
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