Radiation induced leakage current in floating gate memory cells

Single ions impacting on SiO/sub 2/ layers generate tracks of defects which may result in a Radiation Induced Leakage Current (RILC). This current is usually studied as the cumulative effect of ion-induced defects in capacitors with ultra-thin oxides. We are demonstrating and modeling this phenomenon in 10 nm oxides by using Floating Gate memories. The impact of a single, high-LET ion can result in severe retention problems, due to several electrically active defects, which cooperate to slowly discharge the FG. We are also proposing innovative simulation tools to reproduce this phenomenon. Results from simulations fully explain our results, and also agree with existing data on thinner (4 nm) oxides.