An enhanced lumped element electrical model of a double barrier memristive device

Abstract

The massive parallel approach of neuromorphic circuits leads to effective methods for solving complex problems. It has turned out that resistive switching devices with a continuous resistance range are potential candidates for such applications. These devices are memristive systems -nonlinear resistors with memory. They are fabricated in nanotechnology and hence parameter spread during fabrication may aggravate reproducible analyses. This issue makes simulation models of memristive devices worthwhile.Kinetic Monte-Carlo simulations based on a distributed model of the device can be used to understand the underlying physical and chemical phenomena. However, such simulations are very time-consuming and neither convenient for investigations of whole circuits nor for real-time applications, e.g. emulation purposes. Instead, a concentrated model of the device can be used for both fast simulations and real-time applications, respectively. We introduce an enhanced electrical model of a valence change mechanism (VCM) based double barrier memristive device (DBMD) with a continuous resistance range. This device consists of an ultra-thin memristive layer sandwiched between a tunnel barrier and a Schottky-contact. The introduced model leads to very fast simulations by using usual circuit simulation tools while maintaining physically meaningful parameters.Kinetic Monte-Carlo simulations based on a distributed model and experimental data have been utilized as references to verify the concentrated model.

Unsupervised Hebbian learning experimentally realized with analogue memristive crossbar arrays

“…The underlying physical mechanism of the device behaviour has been described in detail in 36 – 38 and is based on the movement of oxygen ions within the Nb x O y layer under the applied electric bias field. Under positive bias voltages, the electric field across the Nb x O y layer ensures that negatively charged oxygen ions drift towards the Au interface.…”

“…In those devices an ultra-thin memristive layer is incorporated in between a tunnel and a Schottky barrier with the benefit that the tunnel barrier limits current through the device. The resistance switching takes place at the insulator-metal interface (Schottky contact), where the ion motion under applied electrical fields lead to a variation of the energy barrier of the Schottky contact 36 – 38 . These memristive devices are used as hardware synapses together with software neurons in a mixed signal circuit which allows unsupervised Hebbian learning of visual patterns.…”

Underlying Physics of Conductive Polymer Composites and Force Sensing Resistors (FSRs) under Static Loading Conditions

“…Conversely, the experimental setup from Figure 10 ensures that the voltage across the sensor is constant and independent of the applied stress. In fact, memristive devices benefit from the non-linear voltage-dependent behavior of the tunneling resistance for exhibiting memory curves [ 49 ].…”

Wave digital model of a TiN/Ti/HfO2/TiN memristor

“…In this composition, the top and the bottom electrode of the resistive switching device are composed of titanium nitride. Hafnium oxide is the dielectric layer often called as the memristive layer in the context of memristive devices and systems . The proposed structure includes a thin titanium layer between the top electrode and the dielectric.…”

“…In the context of wave digital filters, such models are referred to as reference circuits. As an example, in Solan et al, the procedure starting from a physical description of a memristive device up to a concentrated model is shown in detail.…”