The detailed understanding of read-disturb and retention failure of flash memories is essential for further reliability improvement and supply/geometry scaling. In this work we present recent results on the physical modeling of flash disturb characteristics. We show experimental data suggesting that the anomalous leakage current in flash memories is driven by single weak-spot leakage effects. Then we present a detailed trap-assisted tunneling model including one-trap-and multitrap-effects. The implication of defect-clustering on the stress-induced leakage current enhancement are quantitatively addressed. (C) 2002 Elsevier Science Ltd. All rights reserved.