TY - JOUR

T1 - Charge Transport Mechanism in Atomic Layer Deposited Oxygen-Deficient TaOx Films

AU - Gismatulin, Andrei

AU - Gritsenko, Vladimir

AU - Perevalov, Timofey

AU - Kuzmichev, Dmitry

AU - Chernikova, Anna

AU - Markeev, Andrey

N1 - Funding Information: XPS studies were supported by the Russian Science Foundation (project no. 18‐19‐00527). TaO‐based cells fabrication was supported by the Ministry of Science and Higher Education of the Russian Federation (agreement #075‐00337‐20‐03, project FSMG‐2020‐0001). This work used equipment of the MIPT Shared Facilities Centre supported by the Ministry of Education and Science of Russian Federation. The experimental data simulation was conducted with the support of the Russian state research 0306‐2019‐0005. The authors are grateful to the Analytical and Technological Research Center “High Technology and Nanostructured Materials” of NSU. The ab initio simulation study was conducted using the Siberian Supercomputer Center (ICMMG SB RAS) resources. x Publisher Copyright: © 2020 Wiley-VCH GmbH Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2021/3

Y1 - 2021/3

N2 - TaOx is a promising candidate for random access memory formation. To provide the possibility of 3D integration, it is grown by the atomic layer deposition (ALD). Herein, such properties of the pristine TaOx grown by radical-enhanced ALD (REALD) as oxygen vacancies concentration and the trap energy are evaluated to reveal whether it can replace more common ion-sputtered TaOx both in filamentary and nonfilamentary resistive random access memory (ReRAM) stacks. For this purpose, charge transport mechanism in the TiN/TaOx/Pt stacks is analyzed. It is found that charge transport through TaOx is described by the phonon-assisted tunneling between traps model. The thermal Wt = 0.85 eV and optical Wopt = 1.7 eV trap energies are determined. The trap concentration N = 1 × 1021cm−3 found from transport corresponds well with the oxygen vacancy concentration, obtained by ab initio simulation of valence band X-ray photoelectron spectrum. Derived parameters are typical for the ion-sputtered TaOx. As a result, it can be considered to replace ion-sputtered TaOx in the nonfilamentary bilayer stacks. Moreover, the observed properties explain the possibility to achieve electroforming-free resistive switching in a single layer REALD grown TaOx-based stack in combination with extracting Ta electrode.

AB - TaOx is a promising candidate for random access memory formation. To provide the possibility of 3D integration, it is grown by the atomic layer deposition (ALD). Herein, such properties of the pristine TaOx grown by radical-enhanced ALD (REALD) as oxygen vacancies concentration and the trap energy are evaluated to reveal whether it can replace more common ion-sputtered TaOx both in filamentary and nonfilamentary resistive random access memory (ReRAM) stacks. For this purpose, charge transport mechanism in the TiN/TaOx/Pt stacks is analyzed. It is found that charge transport through TaOx is described by the phonon-assisted tunneling between traps model. The thermal Wt = 0.85 eV and optical Wopt = 1.7 eV trap energies are determined. The trap concentration N = 1 × 1021cm−3 found from transport corresponds well with the oxygen vacancy concentration, obtained by ab initio simulation of valence band X-ray photoelectron spectrum. Derived parameters are typical for the ion-sputtered TaOx. As a result, it can be considered to replace ion-sputtered TaOx in the nonfilamentary bilayer stacks. Moreover, the observed properties explain the possibility to achieve electroforming-free resistive switching in a single layer REALD grown TaOx-based stack in combination with extracting Ta electrode.

KW - current transport

KW - oxygen vacancies

KW - tantalum oxide

KW - traps

KW - THIN-FILMS

KW - TRAPS

KW - DEVICE

KW - CONDUCTION

UR - http://www.scopus.com/inward/record.url?scp=85096680064&partnerID=8YFLogxK

U2 - 10.1002/pssb.202000432

DO - 10.1002/pssb.202000432

M3 - Article

AN - SCOPUS:85096680064

VL - 258

JO - Physica Status Solidi (B): Basic Research

JF - Physica Status Solidi (B): Basic Research

SN - 0370-1972

IS - 3

M1 - 2000432

ER -