Can Atmospheric Neutrons Induce Soft Errors in nand Floating Gate Memories?

Abstract

Atmospheric neutrons can interact with the matter inside a microelectronic chip and generate ionizing particles, which in turn can change the state of one or more memory bits [soft error (SE)]. In this letter, we show that SEs are possible in Flash memories, although with extremely low probabilities. While this problem will increase for future technologies, we do not expect SEs to be the reliability limiting factor for further Floating Gate scaling.Index Terms-Atmospheric neutron, flash memories, soft error (SE) rate.

Soft errors induced by natural radiation at ground level in floating gate flash memories

“…Cellere et al [1][2] and Gerardin et al [3][4] have been the first to clearly state, using accelerated tests, that atmospheric neutron-induced soft error occurrence is possible in flash memories, although with extremely low probabilities at ground level. The exact physical mechanism(s) responsible of the floating-gate (FG) charge loss under natural radiation is(are) still an open issue; however Butt and Alam [5] recently proposed a complete physical model of single event upsets in floating gate memory cells that very satisfactory agrees with experimental data without any fitting parameter or phenomenological assumption.…”

Space and terrestrial radiation effects in flash memories

“…papers were published on neutron sensitivity, also using Monte Carlo simulations to study the energies, LET, and ranges of neutron-induced secondary byproducts [60][61][62][63].…”

Computational Modeling and Monte Carlo Simulation of Soft Errors in Flash Memories

“…The induced current transients and such parasitic charges and defects cause degradation of circuit functionality and/or loss of logical information stored in the FG array in addition to possible global circuit performance degradation. Detailed results of both TID and SEEs in flash memories are available in recent papers or review presentations [4][5][6][7][10][11][12][13].…”

“…In addition, the specific question of their sensitivity to the terrestrial radiation environment has been little studied until now. Cellere et al [4][5] and Gerardin et al [6][7] have been the first to clearly state, using accelerated tests, that atmospheric neutron induced soft error occurrence is possible in flash memories, although with extremely low probabilities at ground level. A vey recent study by Just et al [8], based for the first time on real-time tests performed in a mountain altitude natural environment, has concluded in a similar way: natural atmospheric radiation at ground level can induce soft-errors in flash memories, typically several decades below the soft-error rate (SER) of static RAM (SRAM) of comparable technological nodes.…”