Radiation Tolerant by Design 12-transistor Static Random Access Memory

Memory circuits in the space environment are susceptible to stability and reliability issues caused by charged particles such as α-particles, heavy-ions, electrons, and photons. These particles can create an ion track inside the memory device, leading to an upset in the storage bit. This poses a significant problem for conventional 6T SRAM, which is unable to tolerate such upsets. To address this issue, several authors have proposed radiationhardened SRAM cells to mitigate the upset problem. This paper proposes a 12 transistor-based SRAM cell, the performance parameters of which have been compared with the other referenced memory cells like conventional 6T, QUATRO 10T, QUCCE 12T, and WEQUATRO SRAM cells. The proposed design exhibits high resilience to radiation disturbances. Additionally, it boosts a critical charge (Qc) of 1.6 fC, positioning it as a highly favorable option for deep space applications. The proposed 12T shows higher read stability which is validated by RSNM. Our proposed design shows 2×, 1.6×, 1.4×, and 1.2× higher RSNM than that of the 6T, QUATRO 10T, QUCCE 12T and WEQUATRO SRAM cells. The proposed cell also exhibits lower hold power consumption compared to QUATRO 10T (0.86×), QUCCE 12T (0.40×), and WEQUATRO (0.74×), respectively. Similarly, in terms of area overhead proposed 12T consumes smaller area than WEQUATRO and QUCCE 12T, respectively. Major design metrics such as critical charge (Qc), write ability (determined by Combined Word Line Margin (CWLM)), read stability (determined by RSNM), Hold Power dissipation (HSUBPWR/SUB), Read Access Time (TSUBRA/SUB), Write Access Time (TSUBWA/SUB), area, etc., are conflicting in nature (meaning one can be improved at the expense of another). Therefore, a new design metric called Electrical Quality Metric (EQM) has been developed based on these design metrics. The proposed 12T SRAM cell exhibits the highest value of EQM, proving its superiority to other comparison SRAM cells.