Using Memristor Formalism in Semiconductor Device Modeling

IEEE Electron Device Letters, 2011

This letter proposes a new mathematical model for memristor devices. It builds on existing models and is correlated against several published device characterizations. This letter identifies significant discrepancies between the existing models and published device characterization data. The proposed model addresses these discrepancies. In particular, it allows modeling of memristor-based neuromorphic systems.

Journal of Circuits, Systems, and Computers, 2010

Memristor had been¯rst theorized nearly 40 years ago by Prof. Chua, as the fourth fundamental circuit element beside the three existing elements (Resistor, Capacitor and Inductor) but because no one has succeeded in building a memristor, it has long remained a theoretical element. Some months ago, Hewlett-Packard (hp) announced it created a memristor using a TiO 2 =TiO 2ÀX structure. In this paper, the characteristics, structures and relations for the invented hp's memristor are brie°y reviewed and then two general SPICE models for the charge-controlled and°ux-controlled memristors are introduced for the¯rst time. By adjusting the model parameters to the hp's memristor characteristics some circuit properties of the device are studied and then two important memristor applications as the memory cell in a nonvolatile-RAM structure and as the synapse in an arti¯cial neural network are studied. By utilizing the introduced models and designing the appropriate circuits for two most important applications; a nonvolatile memory structure and a programmable logic gate, circuit simulations are done and the results are presented. . Downloaded from www.worldscientific.com by LOUISIANA STATE UNIVERSITY TROY H MIDDLETON LIBRARY -SERIALS DEPARTMENT on 11/29/12. For personal use only.

2014

Memristor, the fourth fundamental passive circuit element, was first postulated by Prof. Leon Chua in 1971. Physical implementation of novel device Memristor and its mathematical model was first demonstrated by HP Labs research team in 2008.Memristor is getting a considerable attention due to its diversified areas of applications from computing to neuromorphic areas. For its reliable implementation in complex circuits various models are discussed. This paper is a brief review on Memristive systems such as current controlled Memristive system (CCMS) and voltage controlled Memristive system (VCMS). A comparative study of different SPICE modeling of memory resistor (Memristor):Non-linear dopant drift model, linear dopant drift model is discussed in this paper.

2016

It is observed that the inductive and capacitive features of the memristor reflect (and are a quintessence of) such features of any resistor. The very presence of the voltage and current state variables, associated by their electrodynamics sense with electrical and magnetic fields, in the resistive characteristic v = f(i), forces any resister to accumulate some magnetic and electrostatic fields and energies around itself, i.e. L and C elements are always present. From the circuit-theoretic point of view, the role of the memristor is seen, first of all, in the elimination of the use of a unique v(i). This makes circuits with hysteresis characteristics relevant, and also suggests that the concept of memristor should influence the basic problem of definition of nonlinearity. Since the memristor mainly originates from the resistor, it was found necessary to overview some unusual cases of resistive circuits. The present opinion is that the framework of basic circuit theory and its connec...

2018

The memory resistor abbreviated memristor was a harmless postulate in 1971. In the decade since 2008, a device claiming to be the missing memristor is on the prowl, seeking recognition as a fundamental circuit element, sometimes wanting electronics textbooks to be rewritten, always promising remarkable digital, analog and neuromorphic computing possibilities. A systematic discussion about the fundamental nature of the device is almost universally absent. This report investigates the assertion that the memristor is a fundamental passive circuit element, from the perspective that electrical engineering is the science of charge management. With a periodic table of fundamental elements, we demonstrate that there can only be three fundamental passive circuit elements. The ideal memristor is shown to be an unphysical active device. A vacancy transport model further reveals that a physically realizable memristor is a nonlinear composition of two resistors with active hysteresis.

2010

Since the fourth fundamental element (Memristor) became a reality by HP labs, and due to its huge potential, its mathematical models became a necessity. In this paper, we provide a simple mathematical model of Memristors characterized by linear dopant drift for sinusoidal input voltage, showing a high matching with the nonlinear SPICE simulations. The frequency response of the Memristor's resistance and its bounding conditions are derived. The fundamentals of the pinched i-v hysteresis, such as the critical resistances, the hysteresis power and the maximum operating current, are derived for the first time.

2014 UKSim-AMSS 16th International Conference on Computer Modelling and Simulation, 2014

The memristor, the recently discovered fundamental circuit element, is of great interest for neuromorphic computing, nonlinear electronics and computer memory. It is usually modelled either using Chua's equations, which lack material device properties, or using Strukov's phenomenological model (or models derived from it), which deviates from Chua's definitions due to the lack of a magnetic flux term. It is shown that by modelling the magnetostatics of the memory-holding ionic current (oxygen vacancies in the Strukov memristor), the memristor's magnetic flux can be identified as the flux arising from the ions. This leads to a novel theory of memristance consisting of two components: 1. A memory function which describes how the memristance, as felt by the ions, affects the conducting electrons located in the 'on' part of the device; 2. A conservation function which describes the time-varying resistance in the 'off' part of the device. This model allows for a straightforward incorporation of the ions within the electronic theory and relates Chua's constitutive definition of a memristor with device material properties for the first time.

— While hardware in a computer have developed greatly, users still has faced problems with its speed, and memory in terms of its performance. The recent developments in memristors made it possible to reduce the problems, as memristive models have been be designed to suit the requirements of time. However, different characteristics are expected from memristors depending upon its applications. The paper aims to compare three major models of memristors focusing on their advantages and limitations. It identifies the most suitable model of memristor that satisfies the memristive device conditions. Out of the three models, Voltage threshold adaptive memristor model (VTEAM) fits into the requirements and it has sufficient accuracy and computational efficiency. Keywords— Memristors, VTEAM, Threshold Adaptive Memristor Model, Boundary Condition Model

Proceedings of the IEEE, 2000

This paper presents SPICE ready circuit models that system designers can use to accurately measure the behavior of memristor-based large systems. ABSTRACT | The nonvolatile memory property of a memristor enables the realization of new methods for a variety of computational engines ranging from innovative memristive-based neuromorphic circuitry through to advanced memory applications. The nanometer-scale feature of the device creates a new opportunity for realization of innovative circuits that in some cases are not possible or have inefficient realization in the present and established design domain. The nature of the boundary, the complexity of the ionic transport and tunneling mechanism, and the nanoscale feature of the memristor intro-duces challenges in modeling, characterization, and simulation of future circuits and systems. Here, a deeper insight is gained in understanding the device operation, leading to the development of practical models that can be implemented in current computer-aided design (CAD) tools.

arXiv preprint arXiv:1207.7319, 2012

In 2008, researchers at the Hewlett-Packard (HP) laboratories claimed to have found an analytical physical model for a genuine memristor device [1]. The model is considered for a thin TiO � film containing a region which is highly self-doped with oxygen vacancies and a region which is less doped, i.e., a single-phase material with a built-in chemical inhomogeneity sandwiched between two platinum electrodes. On base of the proposed model, Strukov et al. [1] were able to obtain the characteristic dynamical state equation and current-voltage relation for a genuine memristor. However, some fundamental facts of electrochemistry have been overlooked by the authors while putting forward their model, namely the coupling of diffusion currents at the boundary between both regions. The device will operate for a certain time like a "chemical capacitor" until the chemical inhomogeneity is balanced out, thus violating the essential requirement on a genuine memristor, the so-called "no energy discharge property". Moreover, the dynamical state equation for the HP-memristor device must fail as this relation violates by itself Landauer's principle of the minimum energy costs for information processing. Maybe, such an approach might be upheld if one introduces an additional prerequisite by specifying the minimum amount of electric power input to the device which is required to continuously change internal, physical states of the considered system. However, we have reasonable doubts with regard to this.