Efficiency evaluation of parametric failure mitigation techniques for reliable SRAM operation

The efficiency of different assist techniques for SRAM cell functionality improvement under the influence of random process variation is studied in this paper. The sensitivity of an SRAM cell functionality metrics when using control voltage level assist techniques is analyzed in read and write operation modes. The efficiency of the assist techniques is estimated by means of parametric analysis. The purpose is to find the degree of functionality metric improvement in each operation mode. The Acceptance Region concept is used for parametric analysis of SRAM cell functionality under random threshold voltage variations. In order to increase the reliability of the SRAM several assist techniques, chosen among the most efficient ones for each operation mode, are considered. This analysis offers a qualitative indication of the cell´s functionality improvement by means of the efficient computation of a metric in parameter domain analysis. The results are proven to have high correlation with the ones obtained by means of the classical Monte Carlo simulations with significant savings in comparing different assist techniques.