SEU/SRAM as a process monitor

The SEU/SRAM is a 4-b static random access memory (SRAM) designed to detect single-event upsets (SEUs) produced by high energy particles. This device is used to determine the distribution in the memory cell spontaneous flip potential. The variance in this potential is determined to be due to the variation in the n-MOSFET threshold voltage. For a 1.2- mu m CMOS process, the standard deviation is found to be 8 mV. Using cumulative distribution and residual plots, stuck cells and nonnormally distributed cells are easily identified.<
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