Universal Thermoelectric Characteristic in Phase Change Memories

Thermoelectric effects play an important role in phase change memory (PCM), where phase transition and atomic migration are accelerated by temperature. A deep understanding of thermoelectric effects may allow a physics-based design of the cell structure and materials to optimize programming speed/energy and reliability. In this work we study the polarity-dependence of PCM characteristics, including crystallization, melting, electrical switching/holding, and ion migration. These characteristics show slower kinetics at negative voltage, which we attribute to thermoelectric effects of electrically-induced heating. We demonstrate a universal correlation of positive/negative kinetics, which we reproduce by modelling Thomson and Peltier heating in the PCM device.