Phase-Change Memory: A Continuous Multilevel Compact Model of Subthreshold Conduction and Threshold Switching

International audienceA Phase-Change Memory (PCM) compact modeling of the threshold switching based on a thermal runaway in Poole-Frenkel conduction is proposed. Although this approach is often used in physical models, this is the first time it is implemented in a compact model. The model accuracy is validated through a good correlation between simulations and experimental data collected on a PCM cell embedded in a 90nm technology. A wide range of intermediate states is measured and accurately modeled with a single set of parameters , allowing multilevel programing. A good convergence is exhibited even in snapback simulation thanks to this fully continuous approach. Moreover, threshold properties extractions indicate a thermally enhanced switching, which validates the ground hypothesis of the model. Finally, it is shown that this model is compliant with a new drift-resilient cell-state metric. Once enriched with a phase transition module, this compact model is ready to be implemented in circuit simulators