Pulsed laser-induced SEU in integrated circuits: a practical method for hardness assurance testing

A pulsed picosecond laser was used to measure the threshold for single event upset (SEU) and single event latchup (SEL) for a detailed study of a CMOS SRAM and a bipolar flip-flop. Comparing the ion and laser upset data for two such vastly different technologies gives a good measure of how versatile the technique is. The technique provided both consistent and repeatable results that agreed with published ion upset data for both types of circuits. However, measurements of the absolute threshold linear energy transfer (LET) using infrared laser light do not agree with those of the ions, being about 50% too high for the SRAMs, and about 20% too high for the bipolar flip-flops. The consistency of the results, together with the advantages of using a laser system, suggests that the pulsed laser can be used for SEU/SEL hardness assurance of integrated circuits.<
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