A study on the short- and long-term effects of X-ray exposure on NAND Flash memories

Abstract

We investigate the effects of X-ray exposure in 41-nm single level NAND Flash memories at small doses, comparable to those used in printed circuit board inspections. We analyze both short-term effects, such as cell threshold voltage shifts during irradiation, and retention and endurance performance of devices exposed to x rays. For doses smaller than 1krad(Si), no effect is observed. At higher doses, charge loss is observed after the exposure and a modest read margin degradation is seen during hightemperature retention tests.