Impact of Heavy-Ion Strikes on Minimum-Size MOSFETs With Ultra-Thin Gate Oxide

In this work we have investigated the effects of irradiation and electrical stress of nanocrystal memory cell arrays. Heavy ion irradiation has no or negligible immediate effects on the nanocrystal MOSFET characteristics, and on the programming window of the cells. By electrically stressing irradiated device, we see accelerated oxide breakdown similar to that previously observed on conventional thin gate oxide MOS capacitors, but no appreciable change of the degradation kinetics in terms of programming window closure and shift. The accelerated breakdown is ascribed to the degradation of the oxide-nitride-oxide (ONO) layer used as control oxide after exposure to ionising irradiation.