Oxygen vacancy filament-based resistive switching in Hf0.5Zr0.5O2 thin films for non-volatile memory

¹Institut Nationale de la Recherche Scientifique, Centre Énergie, Matériaux, Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada

²Munich University of Applied Sciences, Department of Applied Sciences and Mechatronics, Lothstrasse 34, 80335 Munich, Germany

Adv. Mater. Lett., 2019, 10 (6), pp 405-409

DOI: 10.5185/amlett.2019.2225

Publication Date (Web): Jan 10, 2019

Copyright © IAAM-VBRI Press

E-mail: ruediger@emt.inrs.ca

Abstract

The continued evolution of electronic devices relies on the development of new semiconductor memory technology. Given the high compatibility of the Hf_0.5Zr_0.5O₂ thin films with the CMOS technology, we investigate the charge transport mechanisms that occur in a relative thick Hf_0.5Zr_0.5O₂ thin film (4 to 6 nm-thick) when subjected to electrical stresses. To that end we fabricate Hf_0.5Zr_0.5O₂ heterostructures with a Pt tip as the top electrode and TiN and Pt as bottom electrode by radio-frequency magnetron sputtering. After analyzing the surface morphology of the as-received and as-deposited films by atomic force microscopy, the transfer of the desired chemical stoichiometry from the sputtering target to the substrate surface is studied by Raman spectroscopy. The ferroelectricity of the Hf_0.5Zr_0.5O₂ thin films is confirmed by piezoresponse force microscopy measurements, and a retention of 22 h is obtained, attesting to the non-volatility of the samples. Nano-scale electrical measurements reveal the presence of resistive switching, where the low resistance state (ON state) in both Pt-tip/Hf_0.5Zr_0.5O₂/TiN and Pt-tip/Hf_0.5Zr_0.5O₂/Pt heterostructures can be created by the formation of a conductive filament based on oxygen vacancies.

Keywords

Electrical charge transport mechanism, Thin films, CMOS compatible, Nanoscale characterization.