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Cycling-Induced Charge Trapping/Detrapping in Flash Memories—Part II: Modeling

Starting from all the experimental evidence we presented in Part I of this work (Resnati et al., 2016), in this paper, we propose a new microscopic picture for cycling-induced charge trapping/detrapping in Flash memories. This picture involves structural relaxation of the charged tunnel-oxide defects as limiting step in the detrapping process, triggering the possibility for defects to exchange carriers with the substrate. This view is implemented in a statistical model able to reproduce the threshold-voltage instability coming from the phenomenon, including its dependence on cycling dose, temperature, and cell state during idle/bake periods. The model is then used to address some elaborated accelerated testing schemes commonly used to monitor charge trapping/detrapping and its related instability in Flash memories, explaining their results in the context of the new proposed picture of the phenomenon.