Radiation Immune SRAM Cell for Deep Space Applications

Abstract

The reliability of nanoscale memories is largely affected by radiation-induced single-event upsets (SEUs), or soft error. In this paper, we have proposed a 12T radiation-hardened static random access memory (SRAM) cell with exceptionally high radiation tolerance. The proposed cell shows significantly better performance in terms of radiation robustness as compared to other existing radiation-hardened SRAM cells. The WARH12T cell exhibits 1.44x/1.47x/2.10x/8.75x/0.97x write ability or Write static noise margin (WSNM) and 1.04x/1.02x/1.04x/1.36x/1.28x higher read stability or read static noise margin (RSNM) than that of RHBD-10T/RHD-12T/UTSC-12T/NS-10T/PS-10T cells respectively. In addition to this, the cell has only 0.7x/0.73x/0.67x/0.62x/0.21x read access time (TRA) and 0.5x/0.68x/0.64x/0.52x/0.51x write access time (TWA) than that of RHBD-10T/RHD-12T/UTSC-12T/NS-10T/PS-10T cells, respectively. For all these improvements, it incurs a penalty of 1.61x/1.21x/1.25x/1.04x/2.93x in write power (WPWR) as compared to that of RHBD-10T/RHD-12T/UTSC-12T/NS-10T/PS-10T cells at VDD = 1.2 V. Furthermore, the effect of supply voltage variation has been studied by calculating and comparing all the parameters at different supply voltages. To evaluate the effect of process, voltage and temperature (PVT) variations, Monte Carlo simulations are also used for some of the parameters.