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Doping controlled resistive switching dynamics in transition metal oxide thin films

Doping controlled resistive switching dynamics in transition metal oxide thin films
Doping controlled resistive switching dynamics in transition metal oxide thin films
Transition metal oxide thin films have attracted increasing attention due to their potential in non-volatile resistive random access memory (RRAM) devices, where such thin films are used as active layers in metal-insulator-metal (MIM) configurations. Titanium dioxide is one of the most celebrated oxides among the ones that exhibit resistive switching behaviour due to its wide band gap, high thermal stability, and high dielectric constant. RRAM devices with various materials as active layers, have demonstrated very fast switching performance but also huge potential for miniaturisation, which is the bottleneck of FLASH memory. Nevertheless, these devices very often suffer poor endurance, physical degradation, large variability of switching parameters and low yields. In most cases, the physical degradation stems from high electroforming and switching voltages. Doping of the active layer has been often employed to enhance the performance of RRAM devices, like endurance, OFF/ON ratio, forming voltages, etc. In this work, doping in TiO2-x RRAM devices was used to engineer the electroforming and switching thresholds so that device degradation and failure can be delayed or prevented. Al and Nb were selected with basic criteria the ionic radius and the oxidation state. The doped RRAM devices, showed improved switching performance compared to their undoped counterparts. Alternative approaches to doping were also investigated, like multilayer stacks comprising Al2O3-y and TiO2-x thin films. Furthermore, Al:TiO2-x/Nb:TiO2-x bilayer RRAM devices were fabricated, to prove whether a diode behaviour of the p-n interface inside the RRAM was feasible. The latest would be a particularly interesting finding towards active electronics.
University of Southampton
Trapatseli, Maria
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Trapatseli, Maria
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Prodromakis, Themistoklis
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Carta, Daniela
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Kaczmarek, Malgosia
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D'alessandro, Giampaolo
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Mailis, Sakellaris
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Podoliak, Nina
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Mavrona, Eleni
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Khiat, Ali
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Stathopoulos, Spyridon
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Cortese, Simone
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Trapatseli, Maria (2018) Doping controlled resistive switching dynamics in transition metal oxide thin films. University of Southampton, Doctoral Thesis, 116pp.

Record type: Thesis (Doctoral)

Abstract

Transition metal oxide thin films have attracted increasing attention due to their potential in non-volatile resistive random access memory (RRAM) devices, where such thin films are used as active layers in metal-insulator-metal (MIM) configurations. Titanium dioxide is one of the most celebrated oxides among the ones that exhibit resistive switching behaviour due to its wide band gap, high thermal stability, and high dielectric constant. RRAM devices with various materials as active layers, have demonstrated very fast switching performance but also huge potential for miniaturisation, which is the bottleneck of FLASH memory. Nevertheless, these devices very often suffer poor endurance, physical degradation, large variability of switching parameters and low yields. In most cases, the physical degradation stems from high electroforming and switching voltages. Doping of the active layer has been often employed to enhance the performance of RRAM devices, like endurance, OFF/ON ratio, forming voltages, etc. In this work, doping in TiO2-x RRAM devices was used to engineer the electroforming and switching thresholds so that device degradation and failure can be delayed or prevented. Al and Nb were selected with basic criteria the ionic radius and the oxidation state. The doped RRAM devices, showed improved switching performance compared to their undoped counterparts. Alternative approaches to doping were also investigated, like multilayer stacks comprising Al2O3-y and TiO2-x thin films. Furthermore, Al:TiO2-x/Nb:TiO2-x bilayer RRAM devices were fabricated, to prove whether a diode behaviour of the p-n interface inside the RRAM was feasible. The latest would be a particularly interesting finding towards active electronics.

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Published date: August 2018

Identifiers

Local EPrints ID: 423702
URI: http://eprints.soton.ac.uk/id/eprint/423702
PURE UUID: 140a24ad-a082-4cfc-9c61-d8696f75aef3
ORCID for Themistoklis Prodromakis: ORCID iD orcid.org/0000-0002-6267-6909
ORCID for Giampaolo D'alessandro: ORCID iD orcid.org/0000-0001-9166-9356
ORCID for Sakellaris Mailis: ORCID iD orcid.org/0000-0001-8100-2670
ORCID for Nina Podoliak: ORCID iD orcid.org/0000-0002-3146-0355
ORCID for Spyridon Stathopoulos: ORCID iD orcid.org/0000-0002-0833-6209

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Date deposited: 27 Sep 2018 16:30
Last modified: 14 Mar 2019 01:52

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