Estimating and enhancing the yield of tunneling SRAM cells by simulation

Monte Carlo simulations is used to optimize the elements of the circuits external to the TSRAM cell, which greatly relaxed the tolerance of the thickness of the resonant tunneling diodes' (RTD) prebarrier (added just outside one of the tunnel barriers for current reduction, which is essential for TSRAM's low-power operation), from ±0.16 monolayer (ml) to ±0.48 ml for a 99.9% cell-level yield. Results show that additional optimizations at the cell, the architecture, and the system levels will help relax the tolerance and thus enhance the yield further, making TSRAM's commercial adoption more likely.