Sensitive Volume and Extreme Shifts in Floating Gate Cells Irradiated with Heavy Ions

Floating gate cells in 45-nm NOR Flash memories were exposed to highly energetic heavy ions and large irradiation angles. We focused on extreme events, that is the cells with the lowest threshold voltage after irradiation. We discuss the impact of large exposure angles and the shape of the sensitive volume, comparing them with previous-generation devices. We study and model the average and extreme values of threshold voltages, through a combination of experimental measurements and extreme distribution theory, and make an evaluation of worst-case scenarios.