Radiation Tests on 2Gb NAND Flash Memories

Abstract

We report on SEE and TID tests of highly scaled Samsung 2Gbits flash memories. Both in-situ and biased interval irradiations were used to characterize the response of the total accumulated dose failures. The radiation-induced failures can be categorized as followings: single event upset (SEU) read errors in biased and unbiased modes, write errors, and single-event-functional-interrupt (SEFI) failures.

Space and terrestrial radiation effects in flash memories

“…In terms of total ionizing dose effects, charge pumps have been traditionally considered as one of the most radiation-soft building blocks in flash memories [7,14,[38][39][40][41][42]. Given the high voltages at play, the oxides in the charge pump circuitry are subject to particularly high electric fields, causing the failure probability following TID exposure to be large.…”

“…Contrary to other non-volatile technologies, such as phase change memories, which show marginal sensitivity [11,12], flash memories are quite susceptible to the effects of ionizing radiation [7,13,14]. Until a few generations ago, the response to radiation in terms of single event effects and total ionizing dose (TID) effects was mainly dominated by the control circuitry, in particular by the charge pumps that were considered one of the most radiation-soft elements [14]. Then, with feature size scaling, the shrinking of FG cells has led to an increase in the sensitivity to external disturbances, including radiation.…”