Explanation of SILC Probability Density Distributions With Nonuniform Generation of Traps in the Tunnel Oxide of Flash Memory Arrays

In this paper, we develop a detailed physical model to interpret the dependence of the stress induced leakage current (SILC) distributions on the nature and position of the generated defects, and we exploit it to reconsider in detail previously published experimental data on the statistical distribution of the SILC in Flash arrays. We found that a unique symmetrical spatial distribution of traps, which is rapidly decreasing from the Si-SiO₂ interfaces toward the center of the oxide, can explain the oxide-thickness and stress-level dependence of the measured SILC distributions. The generation of cooperating defects with increasing stress time is also analyzed and discussed.