A Reliable TDDB Lifetime Projection Model Verified Using 40Mb STT-MRAM Macro at Sub-ppm Failure Rate To Realize Unlimited Endurance for Cache Applications

We report a reliable TDDB lifetime projection model using power law verified from 40Mb STT-MRAM macro at sub-ppm failure rate to realize nearly unlimited endurance for cache applications. A specially designed macro, having internal temperature control systems and capable of applying accelerated voltage at 40Mb array level with wide operating temperature range: -40~125 °C and varying pulse widths: 200~10 ns, is used for the study. We demonstrate a superior endurance performance of > 1 E 12 cycles at 1 ppm failure rate using 40Mb macro combined with SRAM -like MTJ stack with lower operating voltage at BER ~ 1 ppm at 1 0 ns write pulse.