Reliability Impact of Chalcogenide-Structure Relaxation in Phase-Change Memory (PCM) Cells—Part II: Physics-Based Modeling

Phase-change memory (PCM) cells are affected by structural relaxation (SR), which is the atomic-scale rearrangement of the amorphous phase of the chalcogenide material. Since SR affects the stability of electrical parameters of the PCM cell, such as resistance and threshold voltage, physics-based models for SR are necessary to analyze and predict the device reliability. This paper presents a physical model for SR in amorphous chalcogenide materials, linking the defect annihilation dynamics to the conduction behavior of the cell, hence to the electrical characteristics of the PCM cell. The model is able to predict the PCM cell characteristics as a function of annealing time, temperature, and read conditions.