MBIST and statistical hypothesis test for time dependent dielectric breakdowns due to GOBD vs. BTDDB in an SRAM array

In this paper we present Memory Built-In Self-Test (MBIST) diagnosis methodologies for failure analysis of time-dependent breakdown due to gate oxide breakdown (GOBD) and backend time-dependent dielectric breakdown (BTDDB) in an SRAM array. First, a Built-In Self-Test (BIST) system and algorithm detect the breakdown mechanisms and identify the locations of the faulty sites in SRAM cells. Then, probabilities of failure are estimated for BTDDB and GOBD by matching the observed failure rate from BIST and the expected failure distribution functions from system simulations under realistic use scenarios, with different simulated failure rates for BTDDB and GOBD.