Heavy ion irradiation of floating gate memory cells

Abstract

We have shown results on irradiation of EPROM and Flash devices with Ag and I ions. Bit flip are seldom observed in FG memories, because the control circuitry is by far more radiation sensitive than the memory array itself. Nevertheless, we have shown that, after heavy ions irradiation, cells may experience large threshold voltage shifts. Drain current or threshold voltage shifts are randomly distributed across the device. In particular, charge loss detected after a heavy ion stroke a FG is too large to be described by existing models. The aim of future work is to extend the understanding of the physical mechanism underlying charge loss from the programmed FG.