JART v-ECM v1 var

A purely physics-based variability-aware compact model of voaltile electrochemical metallization memory (v-ECM) cells is presented. Since this extension consists of several different features allowing for a realistic variability-aware fit, it depicts a unique model comprising physics-based, stochastically and experimentally originating variabilities and reproduces them well. It is based on the deterministic nonvolatile ECM model JART ECM v1 and the volatile ECM model JART v-ECM v1. The additional electromotive force (emf) in the later mentioned model as counteracting force is introduced into the equation system enabling the simulation of volatile switching effects. The variability-aware model introduces device-to-device variability by choosing the model parameters from a physically reasonable value range. The cycle-to-cycle variability can be introduced by updating these parameters according to a random walk algorithm after a certain time step. Moreover, a stochastic feature is added to the gap evolution within the model’s main dynamics-determining differential equation. The model is validated by experimental data of Ag/HfO2/Pt ECM cells. This model can be used in higher-level circuit simulators like Spectre to design variability-aware application circuits. [1] (a) 30 cycles of measured I-V sweeps of a Ag-HfO2-Pt ECM device stack are shown. A c2c variability is visible. (b) 30 cycles of simulated I-V sweeps are shown through the usage of the variability-aware volatile ECM model. [2] The experimentally measured threshold switching kinetics data points of a Ag-HfO2-Pt ECM device stack together with their d2d variability are displayed in red, whereas the simulated ones with their d2d variability are displayed in blue. [3] (a) The applied voltage signal to a Ag-HfO2-Pt ECM device stack in the measurement and in the simulation in order to investigate the device’s relaxation behavior. (b) The electric current flows through both devices. Here, a transient zoom of the electric current behavior in the measurement as well as in the simulation is shown around 1.04 ms. Once the current becomes smaller than 70 nA the relaxation time is measured: It is the time duration from the onset of the read voltage to the current crossing 70 nA. (c) Rseries = 560 kΩ, (d) Rseries = 1 MΩ: Measured and simulated relaxation time vs. applied voltage including d2d variability for two different series resistances.