Electrostatic Shielding of NAND Flash Memory from Ionizing Radiation

Abstract

In this paper, we propose and experimentally evaluate an electrostatic shielding technique to protect the health of flash memory cells from ionizing radiation effects. The technique is based on pre-programming the memory module instead of irradiating it in the erase condition. We find that erased cells suffer more oxide degradation compared to programmed cells, suggesting pre-programming of memory modules before deploying in radiation-prone environments. We evaluate cell degradation by performing retention test on the irradiated memory chip which reveals significantly quicker charge loss for memory cells that were in the erased state during irradiation.