As technology size scales down toward lower 2-digit nanometer dimensions, sensitivity of CMOS circuits to radiation effects increases. Static Random Access Memories (SRAMs) that are mostly employed as high performance and high-density memories are prone to radiation induced Single Event Upsets (SEUs). Therefore, designing reliable SRAM cells have always been a serious challenge. In this article, we propose two novel SRAM cells namely RHD11 and RHD13 that provide more attractive features than their latest proposed counterparts. Simulation results show that, our proposed SRAM cells as compared with some state of the art designs have considerably higher robustness against Single Event Multiple Effects (SEMU). Moreover, they offer a sensible area overhead advantage so that, our proposed RHD11 SRAM cell has 19.9% smaller area than the prominent dual interlocked cell (DICE). The simulation results and analyses show that, our proposed SRAM cells especially the proposed RHD13 has a considerable lower failure probability among the considered recent radiation hardened SRAM cells. Index Terms-Soft error, Single Event Upset (SEU), SingleEvent Multiple Effect (SEME), SRAM cell.

Abstract:In this article, two soft error tolerant SRAM cells, the so-called RATF1 and RATF2, are proposed and evaluated. The proposed radiation hardened SRAM cells are capable of fully tolerating single event upsets (SEUs).Moreover, they show a high degree of robustness against single event multiple upsets (SEMUs). Over the previous SRAM cells, RATF1 and RATF2 offer lower area and power overhead. The Hspice simulation results through comparison with some prominent and state-of-the-art soft error tolerant SRAM cells show that our proposed robust SRAM cells have smaller area overhead (RAFT1 offers 58% smaller area than DICE), lower power delay product (RATF1 offers 231.33% and RATF2 offers 74.75% lower PDP compared with DICE), much more soft error robustness, and larger noise margins.