Cycling-Induced Charge Trapping/Detrapping in Flash Memories—Part I: Experimental Evidence

By using our 16-nm NAND Flash technology as a test vehicle, in this paper, we summarize all the experimental evidence that we have gathered so far on the phenomenology of cycling-induced charge trapping/detrapping in Flash memories. In particular, results from experiments conceived to explore the dependence of charge detrapping on cell memory state reveal that the phenomenon involves more than the simple capture and emission of charge carriers in tunnel-oxide defects. Besides, the thermal activation of charge trapping is highlighted for the first time, along with the detailed dynamics leading to the increase of the trapped charge as cell cycling proceeds. These results allow to lay some cornerstones for the microscopic description of cyclinginduced charge trapping/detrapping in Flash memories. From these cornerstones, in the companion paper (Resnati et al., 2016), a new physical picture for the trapping/detrapping processes will be proposed and implemented in a statistical model able to reproduce their corresponding threshold-voltage instabilities over array lifetime.