Unraveling the ferroelectric switching mechanisms in ferroelectric pure and La doped HfO2 epitaxial thin films

Autor: Alexandre Silva, Ignasi Fina, Florencio Sánchez, José P.B. Silva, Luís Marques, Veniero Lenzi
Přispěvatelé: Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, Ministerio de Ciencia e Innovación (España), Fundação para a Ciência e a Tecnologia (Portugal), European Commission
Rok vydání: 2023
Předmět:
Zdroj: Materials Today Physics. 34:101064
ISSN: 2542-5293
Popis: Epitaxial orthorhombic phase La doped HfO2 films are promising for achieving robust ferroelectric polarization without wake-up effect. However, lowering the coercive field is crucial for achieving low-power memory devices. In this work, we have investigated the influence of the La content effect on the structural and ferroelectric properties of epitaxial HfO2 thin films. We show that while the remanent polarization is optimum for 2-5 at. % La-doped HfO2 films, the coercive field is decreased with La doping. The experimental work is supported by density functional theory (DFT) calculations which show that the polarization switching in epitaxial La:HfO2 films can be understood based on the synergetic contribution of the presence of a non-ferroelectric monoclinic phase and the La doping itself that causes a reduction of the nucleation and DW motion energy barriers for the crossing path, which makes it more probable than the non-crossing one.
Financial support from the Spanish Ministry of Science and Innovation (MCIN/AEI/10.13039/501100011033), through the Severo Ochoa FUNFUTURE (CEX2019-000917-S), PID2020-112548RB-I00 and PID2019-107727RB-I00 projects, and from Generalitat de Catalunya (2021 SGR 00804) is acknowledged. We also acknowledge project TED2021-130453B-C21, funded by MCIN/AEI/10.13039/501100011033 and European Union NextGeneration EU/PRTR. This work was supported by: (i) the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding Contract UIDB/04650/2020; (ii) exploratory project 2022.01740.PDTC and (iii) the European Union's Horizon 2020 research and innovation programme under grant agreement No 958174 (M-ERA-NET3/0003/2021 - NanOx4EStor). J. P. B. S. also thanks FCT for the contract under the Institutional Call to Scientific Employment Stimulus – 2021 Call (CEECINST/00018/2021). A.S. also acknowledges FCT for the PhD grant with reference 2022.13796.BD.
With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).
Databáze: OpenAIRE
Externí odkaz: