Device-Level Variability Impact on SRAM Read Stability in Advanced CMOS Nodes

SRAM is widely used in modern digital systems because it provides fast on-chip data access, but its read operation becomes increasingly fragile as CMOS nodes scale. Recent studies have examined SRAM stability through improved cell designs, noise-margin analysis, and variability-aware approaches, yet the direct effect of transistor-level fluctuation on read instability is still not fully clarified. This article addresses that issue by developing a variability-centered analysis of SRAM read stability under threshold-voltage variation, channel-length fluctuation, and mismatch stress. The results show that read weakness is driven by the loss of internal device balance, which reduces static noise margin and raises failure tendency under realistic variation. The study concludes that SRAM evaluation at advanced CMOS nodes should focus more strongly on variability-driven read behavior rather than only nominal stability. These findings are useful for processors, edge systems, and other memory-intensive chips that require reliable low-voltage SRAM operation.