Total dose experiment on NOR flash and analysis of charge pump failure machanism

摘要

A few commercial NOR Flash memories are investigated in total ionizing dose (TID) experiment, one in dynamic mode, one in static mode, one in hot back-up and one in cold back-up. The experiment shows that the dynamic bias mode in which erasure and program are executed frequently is the worst bias mode and charge pump is most critical to TID effects in dynamic bias. The failure mechanism of charge pump is explained with emphasis, i.e. the threshold voltage drift plays a more critical role in charge pump's performance when the accumulated radiation dose is low while the radiation induced leakage current effects more obviously as the accumulated dose goes high.