Status and challenges of PCM modeling

From the stage of concept-level alternative to Flash memories, the phase-change memory (PCM) is rapidly gaining the status of reference technology for high performance, high endurance next generation non volatile applications. To sustain the development of new and scaled PCM technologies, a comprehensive understanding and modelling of the cell at the material, cell and large-array levels are required. This paper will address the most significant achievements in the electrothermal modelling of PCM single cell. After reviewing the transport modeling in the amorphous and crystalline phases of the chalcogenide material, we focus on the application modeling of the cell, discussing programming current minimization by geometry optimization, trade-off between programming current and readout resistance and the program disturb issue. Scaling of the PCM is extensively addressed, comparing isotropic and non isotropic scaling and the respective impact on cell reliability. The open issues for PCM physical modeling are finally pointed out.