Variability-Aware Design Space Exploration of Embedded Memories

With scaling of process technologies and worsening of process variations, embedded memories are susceptible to a large number of failure mechanisms making it hard to achieve high yield. In this paper, by bringing together architecture and circuit-level exploration tools, we analyse the impact of process variations on static random access memory (SRAM) cell stability and determine the impact of SRAM failures on memory functional yield. We then detail the importance of repair mechanisms such as error correcting codes (ECC) and redundancy on improving yield subject to constraints set on power and area. Finally, we show that a design paradigm orthogonal to traditional repair mechanisms involving redefinition of the yield criterion by accepting memories with failures is a promising candidate for improving yield without incurring additional overheads.