A radiation hardened In-memory computing SRAM for soft error tolerance in safety critical applications

In this paper, a radiation-hardened, soft error tolerant 14T SRAM cell (RHBD-IMC14T) featuring in memory computing (IMC) with enhanced reliability is proposed. It has only three sensitive nodes and a separate read path which improves read stability, making the design suitable for IMC operations. It is able to perform OR/NOR, AND/NAND, XOR/XNOR operations, binary content addressable memory (BCAM), and ternary content addressable memory (TCAM) searches efficiently. All the performance comparisons are done in UMC 65 nm technology at 1.2 V, and it achieves 1.2$\times$ , 1.2$\times$ , 1.1$\times$ 1.9$\times$ times higher write stability and 1.2$\times$ , 1.2$\times$ , 6.6$\times$ , 1.4$\times$ times lower power dissipation compared to DICE12T, QUCCE12T, RHSC12T, and RHBD13T, respectively. It also shows a 65% reduction in single event upset probability (P${}_S$) over DICE12T. The logic operations are performed at 12.52 GHz with an energy consumption of 6.72 fJ/bit. The BCAM and TCAM operations achieve energy efficiencies of 53.53 fJ/bit/search and 51.98 fJ/bit/search at frequencies of 4.06 GHz and 4.26 GHz, respectively. RHBD-IMC14T has critical charge of Qc $>$ 34 fC, ensuring soft error resilience. This work represents one of the earliest efforts to integrate RHBD techniques into IMC capable SRAMs, with robust and energy efficient memory computing for safety critical applications.