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A double barrier memristive device.

Hansen M, Ziegler M, Kolberg L, Soni R, Dirkmann S, Mussenbrock T, Kohlstedt H - Sci Rep (2015)

Bottom Line: A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism.In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively.The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

View Article: PubMed Central - PubMed

Affiliation: Nanoelektronik, Technische Fakultät Kiel, Christian-Albrechts-Universität Kiel, Kiel 24143, Germany.

ABSTRACT
We present a quantum mechanical memristive Nb/Al/Al2O3/NbxOy/Au device which consists of an ultra-thin memristive layer (NbxOy) sandwiched between an Al2O3 tunnel barrier and a Schottky-like contact. A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism. In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively. The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

No MeSH data available.


Local electrical field strengths.Calculated electrical fields across the Schottky contact ES, the NbyOx layer EI (b), and across the tunnelling barrier ET (b) during a positive voltage sweep. The onset current of the Schottky diode for the LRS and HRS are marked in red and blue, respectively. The black arrows show the direction of the voltage sweep. Inset: Corresponding change in effective tunneling distance.
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f6: Local electrical field strengths.Calculated electrical fields across the Schottky contact ES, the NbyOx layer EI (b), and across the tunnelling barrier ET (b) during a positive voltage sweep. The onset current of the Schottky diode for the LRS and HRS are marked in red and blue, respectively. The black arrows show the direction of the voltage sweep. Inset: Corresponding change in effective tunneling distance.

Mentions: Figure 6 shows the calculated electric field strengths for positive bias voltages across the tunneling barrier ET, the interfacial layer of the double barrier device EI, and the Schottky contact ES. At low bias voltages the electrical field across the interfacial layer (Fig. 6(b)) and the tunneling layer (Fig. 6(c)) is nearly zero, since the current is blocked by the Schottky contact (Fig. 6(a)). In other words, the Schottky diode defines a threshold voltage for our device, which has to be exceeded to change the resistance of the device. This can be seen from the inset of Fig. 6(a), which shows the change of the effective tunneling distance as a function of the applied external voltage. Here, the resulting electrical field across the NbxOy layer is too small to affect either ion diffusion or electron injections in the reverse diode regime. It is worth to mention that the device threshold additionally depends on the particular resistance state of the device, as marked by blue and red dotted lines in Fig. 6(a–c) for the HRS and LRS, respectively. This opens the possibility to adjust the device threshold by the memristive state of the device, which may be of interest in neuromorphic circuits to emulate threshold dependent plasticity processes, or for ultra dense packet crossbar memory arrays to suppress sneak-path leakage currents43.


A double barrier memristive device.

Hansen M, Ziegler M, Kolberg L, Soni R, Dirkmann S, Mussenbrock T, Kohlstedt H - Sci Rep (2015)

Local electrical field strengths.Calculated electrical fields across the Schottky contact ES, the NbyOx layer EI (b), and across the tunnelling barrier ET (b) during a positive voltage sweep. The onset current of the Schottky diode for the LRS and HRS are marked in red and blue, respectively. The black arrows show the direction of the voltage sweep. Inset: Corresponding change in effective tunneling distance.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562229&req=5

f6: Local electrical field strengths.Calculated electrical fields across the Schottky contact ES, the NbyOx layer EI (b), and across the tunnelling barrier ET (b) during a positive voltage sweep. The onset current of the Schottky diode for the LRS and HRS are marked in red and blue, respectively. The black arrows show the direction of the voltage sweep. Inset: Corresponding change in effective tunneling distance.
Mentions: Figure 6 shows the calculated electric field strengths for positive bias voltages across the tunneling barrier ET, the interfacial layer of the double barrier device EI, and the Schottky contact ES. At low bias voltages the electrical field across the interfacial layer (Fig. 6(b)) and the tunneling layer (Fig. 6(c)) is nearly zero, since the current is blocked by the Schottky contact (Fig. 6(a)). In other words, the Schottky diode defines a threshold voltage for our device, which has to be exceeded to change the resistance of the device. This can be seen from the inset of Fig. 6(a), which shows the change of the effective tunneling distance as a function of the applied external voltage. Here, the resulting electrical field across the NbxOy layer is too small to affect either ion diffusion or electron injections in the reverse diode regime. It is worth to mention that the device threshold additionally depends on the particular resistance state of the device, as marked by blue and red dotted lines in Fig. 6(a–c) for the HRS and LRS, respectively. This opens the possibility to adjust the device threshold by the memristive state of the device, which may be of interest in neuromorphic circuits to emulate threshold dependent plasticity processes, or for ultra dense packet crossbar memory arrays to suppress sneak-path leakage currents43.

Bottom Line: A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism.In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively.The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

View Article: PubMed Central - PubMed

Affiliation: Nanoelektronik, Technische Fakultät Kiel, Christian-Albrechts-Universität Kiel, Kiel 24143, Germany.

ABSTRACT
We present a quantum mechanical memristive Nb/Al/Al2O3/NbxOy/Au device which consists of an ultra-thin memristive layer (NbxOy) sandwiched between an Al2O3 tunnel barrier and a Schottky-like contact. A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism. In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively. The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

No MeSH data available.