Modeling of crystallization kinetics in phase change memories for set and read disturb regimes

Crystallization speed in PCM controls data retention [1], set transition [2], program disturb [3] and read disturb [4], thus playing a central role in dictating the cell and array characteristics. To provide a comprehensive model for reliability and programming in PCM, the crystallization of the amorphous phase must be thoroughly understood. This work studies set transition and read disturb in PCM devices. We introduce a new technique for studying crystallization at extremely low currents (< 50 µA), which are normally not accessed in standard set experiments. We develop a model for filamentary crystallization in the PCM, accounting for the observed crystallization regimes. Read disturb is studied as a function of the initial state and of the read current, allowing the development of a unified crystallization model for set and read disturb in PCM.