As technology advances continue reducing transistor features, microscopic variations in number and location of dopant atoms in the channel region induce increasing electrical deviations in device parameters such as the threshold voltage. Deviations refer to mismatches with respect to device parameters at design time. These deviations are specially important in SRAM cells whose transistors are constructed with minimum geometry to fulfill area constraints, since they can cause some cells to fail.
In this paper, we study the impact of threshold voltage variations in the stability of the cell for a 16nm technology node. The failure probability has been studied for the four types of SRAM failures: write, access, read, and hold. We found that, under the assumed experimental conditions, the two former types of failures can be reduced by increasing the wordline pulse width of the cell. Experimental results show that access failures can be reduced up to 43.9% and write failures around 23.4% by enlarging the wordline pulse by 5 times the nominal width.