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Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes.

Bai Y, Wu H, Wang K, Wu R, Song L, Li T, Wang J, Yu Z, Qian H - Sci Rep (2015)

Bottom Line: The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale.Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized.Furthermore, the discussion of high array density potential is presented.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microelectronics, Tsinghua University, Beijing, China, 100084.

ABSTRACT
There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented.

No MeSH data available.


The conductive mechanism of 3D Ta2O5-x/TaOy RRAM with graphene edge electrode in (a) HRS and (b) LRS, fitted to Schottky emission model and electron hopping model respectively.Insets show the fitting curves and corresponding fitting parameters.
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f4: The conductive mechanism of 3D Ta2O5-x/TaOy RRAM with graphene edge electrode in (a) HRS and (b) LRS, fitted to Schottky emission model and electron hopping model respectively.Insets show the fitting curves and corresponding fitting parameters.

Mentions: Furthermore, It is necessary to investigate the mechanism when the edge electrode scaling to sub-nanometer. Therefore, The temperature dependent transport characteristics in HRS and LRS are studied to understand the conduction mechanism. Figure 4 shows that electrical measurement results in HRS are well fitted with Schottky barrier emission. While the electron transport is facilitated by electron hopping for LRS state. The conduction mechanism is quite similar with our previous study11. Therefore we propose a possible switching mechanism of graphene electrode based 3D RRAM: The mechanism is still caused by the formation/rupture of conductive filaments. And the filaments formation/rupture happen at the pillar electrode Pt/Ta2O5-x interface, other than graphene/TaOy interface. During forming process, the oxygen vacancies in TaOy layer move to Ta2O5-x layer, at the Pt/Ta2O5-x the conductive filaments are formed. On the graphene/TaOy side, there are a lot of oxygen vacancies in TaOy which has good conductivity. Electrons could transport from graphene to TaOy easily and enough current could be supplied. Since the graphene electrode has little effects on this process, it is possible that the filament size is still in several-nanometers order, which could be larger than graphene electrode.


Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes.

Bai Y, Wu H, Wang K, Wu R, Song L, Li T, Wang J, Yu Z, Qian H - Sci Rep (2015)

The conductive mechanism of 3D Ta2O5-x/TaOy RRAM with graphene edge electrode in (a) HRS and (b) LRS, fitted to Schottky emission model and electron hopping model respectively.Insets show the fitting curves and corresponding fitting parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562297&req=5

f4: The conductive mechanism of 3D Ta2O5-x/TaOy RRAM with graphene edge electrode in (a) HRS and (b) LRS, fitted to Schottky emission model and electron hopping model respectively.Insets show the fitting curves and corresponding fitting parameters.
Mentions: Furthermore, It is necessary to investigate the mechanism when the edge electrode scaling to sub-nanometer. Therefore, The temperature dependent transport characteristics in HRS and LRS are studied to understand the conduction mechanism. Figure 4 shows that electrical measurement results in HRS are well fitted with Schottky barrier emission. While the electron transport is facilitated by electron hopping for LRS state. The conduction mechanism is quite similar with our previous study11. Therefore we propose a possible switching mechanism of graphene electrode based 3D RRAM: The mechanism is still caused by the formation/rupture of conductive filaments. And the filaments formation/rupture happen at the pillar electrode Pt/Ta2O5-x interface, other than graphene/TaOy interface. During forming process, the oxygen vacancies in TaOy layer move to Ta2O5-x layer, at the Pt/Ta2O5-x the conductive filaments are formed. On the graphene/TaOy side, there are a lot of oxygen vacancies in TaOy which has good conductivity. Electrons could transport from graphene to TaOy easily and enough current could be supplied. Since the graphene electrode has little effects on this process, it is possible that the filament size is still in several-nanometers order, which could be larger than graphene electrode.

Bottom Line: The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale.Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized.Furthermore, the discussion of high array density potential is presented.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microelectronics, Tsinghua University, Beijing, China, 100084.

ABSTRACT
There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented.

No MeSH data available.