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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.


Device model.(a) Equivalent circuit model of a double barrier memristive device. The tunnelling current is defined by a current source supplying the current according to Equation 4. The Schottky barrier is taken into account as a diode according to Equation 1. The capacitance of the tunnelling barrier is CT, while CI represents the capacitance of the NbxOy layer. The oxygen-ion migration, which changes the interfacial potential VI, is expressed in the model as a variable resistance RI(x) parallel to the NbxOy layer capacitance CI. The local electrical field strength ES, EI, and ET due to the applied voltage are indicated as a red line. (b) Calculated I–V curve for a variable tunneling distance and (c) for a constant tunneling distance.
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f5: Device model.(a) Equivalent circuit model of a double barrier memristive device. The tunnelling current is defined by a current source supplying the current according to Equation 4. The Schottky barrier is taken into account as a diode according to Equation 1. The capacitance of the tunnelling barrier is CT, while CI represents the capacitance of the NbxOy layer. The oxygen-ion migration, which changes the interfacial potential VI, is expressed in the model as a variable resistance RI(x) parallel to the NbxOy layer capacitance CI. The local electrical field strength ES, EI, and ET due to the applied voltage are indicated as a red line. (b) Calculated I–V curve for a variable tunneling distance and (c) for a constant tunneling distance.

Mentions: Figure 5(a) shows the equivalent circuit which was used to model the scenario from Fig. 1(a), where both, mobile oxygen ions and interfacial trap states, are responsible for the observed resistive switching mechanism. The calculated I–V curve shown in Fig. 5(b) contains the main experimental recorded characteristics, such as an asymmetric pinched hysteresis, a high resistance at small voltages and the current saturation at higher voltages. In contrast, Fig. 5(c) shows the simulated I–V curve for a constant effective tunneling distance deff. In agreement with our experimental findings (cf. Fig. 3(b,c)) this decoupling of the particular interfacial interactions reduces the width of the memristive hysteresis, indicating that mobile oxygen-ions are involved in the resistance switching process and that the two interfaces cannot be treat separately.


A double barrier memristive device.

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

Device model.(a) Equivalent circuit model of a double barrier memristive device. The tunnelling current is defined by a current source supplying the current according to Equation 4. The Schottky barrier is taken into account as a diode according to Equation 1. The capacitance of the tunnelling barrier is CT, while CI represents the capacitance of the NbxOy layer. The oxygen-ion migration, which changes the interfacial potential VI, is expressed in the model as a variable resistance RI(x) parallel to the NbxOy layer capacitance CI. The local electrical field strength ES, EI, and ET due to the applied voltage are indicated as a red line. (b) Calculated I–V curve for a variable tunneling distance and (c) for a constant tunneling distance.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Device model.(a) Equivalent circuit model of a double barrier memristive device. The tunnelling current is defined by a current source supplying the current according to Equation 4. The Schottky barrier is taken into account as a diode according to Equation 1. The capacitance of the tunnelling barrier is CT, while CI represents the capacitance of the NbxOy layer. The oxygen-ion migration, which changes the interfacial potential VI, is expressed in the model as a variable resistance RI(x) parallel to the NbxOy layer capacitance CI. The local electrical field strength ES, EI, and ET due to the applied voltage are indicated as a red line. (b) Calculated I–V curve for a variable tunneling distance and (c) for a constant tunneling distance.
Mentions: Figure 5(a) shows the equivalent circuit which was used to model the scenario from Fig. 1(a), where both, mobile oxygen ions and interfacial trap states, are responsible for the observed resistive switching mechanism. The calculated I–V curve shown in Fig. 5(b) contains the main experimental recorded characteristics, such as an asymmetric pinched hysteresis, a high resistance at small voltages and the current saturation at higher voltages. In contrast, Fig. 5(c) shows the simulated I–V curve for a constant effective tunneling distance deff. In agreement with our experimental findings (cf. Fig. 3(b,c)) this decoupling of the particular interfacial interactions reduces the width of the memristive hysteresis, indicating that mobile oxygen-ions are involved in the resistance switching process and that the two interfaces cannot be treat separately.

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.