Soft Error Immunity of Subthreshold SRAM

Abstract—This paper discusses soft error immunity of sub-threshold SRAM presenting neutron- and alpha-induced soft error rates (SER) in 65-nm 10T SRAM over a wide range of supply voltages from 1.0 to 0.3 V. The results show that the neutron-induced SER at 0.3 V is 7.8 times as high as that at 1.0 V. The measured multiple cell upsets (MCUs) included 8-bit MCU. With 0.4V operation of the SRAM under test, protons are not dominant secondary particles causing SEU, but this paper points out that protons must be considered for future near-threshold computing. The alpha-induced SER at 0.3V is 6x higher than that at 1.0V. These results can contribute to reliability estimation and enhancement in subthreshold circuit design. I