Bit-slice logic interleaving for spatial multi-bit soft-error tolerance

Semiconductor devices are becoming more susceptible to single event upsets (SEUs) as device dimensions, operating voltages and frequencies are scaled. The majority of architecture-, logic- and circuit-level techniques that have been developed to address SEUs in logic assume a single-point fault model. This will soon be insufficient as the occurrence of spatial multi-bit errors is becoming prevalent in highly scaled devices. In this paper, we explore this new fault model and evaluate the effectiveness of conventional fault tolerance techniques to mitigate such faults. We also extend the idea of bit interleaving in memory to logic bit slices and explore its utility as an approach to spatial multi-bit error mitigation in logic. We present a comparison of these techniques using a case study of a Brent-Kung adder at a 90-nm process.