Transient response exploration of SRAM cell metastable states caused by ionizing radiation with 3D mixed mode simulation

This paper reports on the simulation and experimental results examining the interaction between mismatch and soft-errors in SRAM cells. Multiple bit upsets (MBU) due to ion irradiation are measured and show a significant probability of not upsetting otherwise identical cells, including the stored state. In order to understand this behavior, we use 3D device simulations and show that they may be due to the cells being driven metastable by radiation induced collected charge, whence the final state is strongly determined by the circuit mismatch within the cell.