Modeling of bipolar resistive switching of a nonlinear MISM memristor

Abstract

This paper presents a novel mathematical model of the bipolar resistive switching (BRS) of the metal-insulator-semiconductor-metal (MISM) in a Pt/Ta2O5/TaOx/Pt memristor. The proposed model is based on quantum mechanics and describes the BRS behaviour based on electron band theory and the physical characteristics of the metal-insulator-semiconductor (MIS) system. It also includes the physical characteristics of the insulator layer. The novelty of the proposed model lies in incorporating the tunnelling probability factor (TPF) between the semiconductor and the metal layers and therefore demonstrating its effect on the conduction mechanism. In addition, the effect of continuous variation of the interface traps densities and the ideality factor during BRS is modelled using the semiconductor properties and the characteristics of the MIS system. Thus, the model emphasizes the dependency of the memristor current on the physical characteristics of the insulator layer. Moreover, the electric field equation for the active region is derived for the MISM structure which is used, together with the Mott and Gurney rigid point-ion model and the Joule heating effect, to model the oxygen ion migration mechanism. Finally, the model also demonstrates the self-limiting growth of the doped region. Extensive simulation is carried out on the proposed model and the results are correlated against the experimental data which show that the proposed model is in good agreement with the physical characteristics of the MISM memristor.