Statistical Investigation of Random Telegraph Noise ID Instabilities in Flash Cells at Different Initial Trap-filling Conditions

This work investigates the statistical distribution of random telegraph noise drain current instability in flash memory arrays as a function of the initial trap-filling condition. When stationary trap occupancy is established, a symmetrical behavior appears for the positive and the negative tail of the drain current instability distribution. However, when a gate pulse with amplitude different from the read bias is applied just prior to cell drain current monitoring, a preferential direction for the instability results as a consequence of a forced trap state. Finally, the results are explained by our statistical model for random telegraph noise and a defects spectroscopic analysis is presented.