Analysis of phase-transformation dynamics and estimation of amorphous-chalcogenide fraction in phase-change memories

We investigated the current-induced phase transformations in chalcogenide-based memories. By electrical characterization and compact simulation of the memory I - V, we point out the evidence for a stacked distribution of phases as a result of the applied programming pulses. An anomalous cell behavior is also shown, which we explain in terms of parallel phase transition in the cell. A new technique for estimating the amorphous fraction is proposed, requiring only a simple manipulation of I - V characteristics of the memory.