Bias temperature instability aware and soft error tolerant radiation hardened 10T SRAM cell

Abstract

In this paper, we propose an asymmetric radiation-hardened 10T (AS10T) SRAM cell and analyze the impact of bias temperature instabilities (BTI) on the single event upset of the modified structure. For this, we make use of a read decoupled circuit to improve the stability of the reading cycle, and a charge booster circuit to increase the critical charge at the sensitive node of the SRAM cell. First, we compare the noise margin of several reference cells and can clearly observe that the read static noise margin (RSNM) of AS10T is 3.25× higher than as can be achieved for the 6T SRAM cell. This improvement is due to the read decoupled path used for the read operation. To analyze the soft-error hardening, we calculate the critical charge and observe that the critical charge of the proposed AS10T cell exceed the same parameter of other SRAM cells. Further, we perform critical charge simulations and stability analysis considering BTI and observe that the AS10T SRAM cell is also less affected by BTI as the reference cells.