Radiation effects on advanced flash memories

Flash memory cells data loss caused by total ionizing dose and heavy ions

“…Characterisation curves for drain current as a function of gate voltage for transistors in programmed and erased states are shown in Figure 3. Recently it was believed that the flash memory cells were much less sensitive to ionizing radiation compared to control circuitry and charge pumps [2], but scaling of advanced flash memory has led to its sensitivity increasing.…”

Total Ionizing Dose (TID) Tests on Non-Volatile Memories: Flash and MRAM

“…The same sequence of read/erase/verify/program/read applied to many earlier studies of TID on flash memory devices. The first generation of NAND flash memories failed to erase at the very low dose rate of 10krad(Si) [4].…”

“…Only a few blocks cannot be programmed at 100 krad(Si). Previous generations of flash devices showed functional failures after 10-15krad(Si) [4], [7]. The worst case is static biasing during irradiation.…”

“…New generations of shrinking cell area in flash memory complicated the distinction between single event upsets and single-event-functionalinterrupt (SEFI) [2], [3]. One recent study had shown the internal charge pump circuitry damaged by exposing to heavy ions [4]. Other study also revealed that heavy ions had stopped the flash memory devices from erasing and programming the blocks and cells, respectively [5].…”

<title>Integrated extension board for on-board computer (OBDH) of SSETI ESEO satellite</title>

“…In addition, special commands can be sent to AuxBoard to obtain information on quantity of SEL & SEU experienced, free memory etc. Flash memories (5 x 28F640 -64Mbits of capacity each) were the largest NOR ones freely available and tested under radiation conditions during design consideration [10]. Memory chips are controlled by Actel ProASIC250 (A3P250) Flash FPGA [11].…”