Faults Due to Process Variations in SRAMs

Abstract

This chapter studies the impact of process variations and parasitic phenomena on SRAM operation. In particular, fault modeling and test solutions are detailed. The first section focuses on threshold voltage deviations within the SRAM core-cell that lead to static and dynamic faults, such as TF and dRDF. Next, it is shown that leakage currents flowing through the pass gates of unselected core-cells may influence the read operation causing leakage read faults (LRFs). The last section of the chapter presents the Complex Read Fault (CRF) that models the cumulative effect of multiple electric phenomena in several SRAM sub-circuits, which contribute to reduce the success of the read operation.