Impact of threshold voltage fluctuation due to random telegraph noise on scaled-down SRAM

The impact of a random telegraph noise (RTN) on a scaled-down SRAM is shown for the first time. To estimate the impact on SRAM, we statistically analyzed a threshold voltage fluctuation (DeltaV_th) of n-and p-MOSFETs. It is revealed that DeltaV_th of the p-MOSFET is larger than that of the n-MOSFET. This difference can be explained by considering the followings: (i) number- and mobility-fluctuation models of RTN (ii) the difference in the capture cross section between electron and hole. In addition, based on these results, SRAM margin enclosed by read / write V_th curves with or without RTN was simulated. We consequently found that V_th margin comes close to V_th window of the SRAM by considering the effect of RTN on DeltaV_th, even at hp 65. Moreover, DeltaV_th due to RTN of the p-MOSFET is comparable with DeltaV_th due to the random dopant fluctuation (RDF) at hp 45 because DeltaV_th due to the RDF is inversely proportional to square root of the gate area (S), while DeltaV_th due to RTN is inversely proportional to S.