Statistical Modeling of Secondary Path During Erase Operation in Phase Change Memories

In this paper, we analyze the read current shifts that have been observed after the erase operations in phase change memory arrays. Experimental data analyses allow detecting statistical features of the current shifts in terms of their occurrence and magnitude, which are consistent with the physical interpretation attributed to the presence or absence of secondary percolation path in parallel to the main one created during the crystallization process. Based on the statistical characterization, we develop a model for the read current that reproduces the measured read current distributions after erase, during cycling, and for different erase pulse durations.