A 32nm SRAM reliability macro for recovery free evaluation of NBTI and PBTI

A scalable test structure for recovery free evaluation of the impact of NBTI and PBTI on read/write operation in a SRAM macro has been developed. A novel non-invasive methodology keeps the stress interrupts for measurements within a few microseconds, preventing unwanted BTI recovery, while providing a parallel stress-measure capability on 32kb sub-arrays. Measurement results in a 32nm high-κ/metal-gate silicon-on-insulator process show that proposed schemes provides 35mV better accuracy in read V_MIN and 10X accuracy in BFR.