Threshold and Characteristic LETs in SRAM SEU Cross Section Curves

Characterizing the sensitivity of a static random access memory (SRAM) to single-event upset (SEU) is an essential task for assuring its soft-error reliability. However, this task often imposes a burden because it usually requires many cycles of accelerator-based irradiation tests. A model recently proposed is a very simple exponential-type equation but has strong potential to reduce the burden because of its capability to predict SEU cross sections in various conditions. The aim of the present study is to revisit the model in terms of threshold parameters called threshold linear energy transfer (LET or L) and critical charge. Although these threshold parameters are widely used as key parameters that describe whether an SEU occurs or not, they are not seen in the model. This article explores such missing threshold parameters, suggesting that they successfully appear by introducing a factor of five to the original expression.