Mathematical Modeling of Bipolar Resistive Switching Mechanism
thesisposted on 28.10.2014, 00:00 authored by Manasi H. Kulkarni
Recently, transition metal oxide materials showing bipolar resistive switching have attracted deep interest. These materials have an application as resistive random access memory (RRAM) which shows advantages over capacitance based RAMs and even other resistance based RAMs as well as memristor devices and neuromorphic memories. Resistive switching is a phenomenon where the dielectric oxide material shows characteristic bi-stable resistance states, a high-resistance state and a low-resistance state, under the action of strong electric field or current . Resistive switching can be classified in two types, unipolar resistive switching and bipolar resistive switching. Unipolar resistive switching is not dependent on applied voltage polarity and the set and reset switching can occur in same or opposite polarities. Whereas, bipolar resistive switching is dependent on polarity of applied voltage, i.e., if the set switching occurs under one polarity, reset switching occurs under another polarity. In this thesis, an advanced mathematical model representing reactions taking place in the Pt/TiO2/Pt resistive cell was created based on the mechanism for bipolar resistive switching explained in Jeong et. al. The model was then modified suiting to a set of experimental results and simulated to compare the results with experimental data. The physical origin of the mechanism behind the bipolar resistive switching effect has been discussed and found to be based on formation and rupture of conduction paths. The mechanism of BRS can be classified into anion- and cation-migration-induced BRS and electronic BRS. The anion-migration-induced mechanism includes the migration of anions, due to the drift-diffusion, and their electrochemical reactions at the interface between the anode and the switching material leads to changes in the resistance. The electronic BRS deals with the resistive switching resulting from the change in electronic transport behavior including the electronic charge injection at the cathode, and the trapping and de-trapping of electronic carriers.