March CRF: an Efficient Test for Complex Read Faults in SRAM Memories

In this paper we study complex read faults in SRAMs, a combination of various malfunctions that affect the read operation in nanoscale memories. All the memory elements involved in the read operation are studied, underlining the causes of the realistic faults concerning this operation. The requirements to cover these fault models are given. We show that the different causes of read failure are independent and may coexist in nanoscale SRAMs, summing their effects and provoking complex read faults, CRFs. We show that the test methodology to cover this new read faults consists in test patterns that match the requirements to cover all the different simple read fault models (non-destructive). We propose a low complexity (~2N) test, March CRF, that covers effectively all the realistic complex read faults.