A new compact model for bipolar RRAMs based on truncated-cone conductive filaments-a Verilog-A approach

A new model for bipolar resistive random-access memories (RRAMs) is presented in this article. Redox and diffusion processes are used to describe in detail the physics behind the filamentary resistive switching (RS) mechanisms of the RRAMs under study. The model includes truncated-cone shaped filaments which are known to be close to the real conductive filament (CF) geometry and a detailed thermal approach, where two temperatures are considered to describe the rupture process at the CF's narrowest part and also the main CF body's electrical conductivity variations. Ti/ZrO2/Pt RRAM devices have been fabricated and measured, and the model has allowed us to reproduce the experimental data for all the cases analyzed. Finally, the model has been implemented in Verilog-A code within the ADS circuit simulator, and the response of a device to pulsed external voltages within a characterization circuit has been simulated, producing good results when compared with experimental measurements.