Macromodeling a phase change memory (PCM) cell by HSPICE

This paper presents a HSPICE macromodel of a phase change memory (PCM) cell. The model simulates not only the resistance change by phase (as corresponding to the two states, amorphous and crystalline), but also the temperature profile, the crystalline fraction during the programming and the drift behavior in resistance and threshold voltage. The proposed macromodel (consisting of two models) generates the I-V and R-I plots of a PCM cell at a very small error compared with experimental data. The electrical-based modeling by HSPICE allows to fully characterize the holding voltage and the continuous behavior of the PCM resistance, while assessing the impact of the programming time. Furthermore, the proposed model takes into account the drift behavior of few parameters when the PCM is not been programmed or read, making the model more realistic. Selection of the parameters is based on operational features, so the electrical characterization of the PCM is simple, easy to simulate and intuitive.