n reproduced from [Norm-98] where it was compiled to show several examples from the literature as the basis for evaluating his formulation of the Burst Generation Rate (BGR) model for predicting latch-up sensitivity in microprocessors. Note the K-5 processor results as fabricated on the 2 micron thick epitaxial material. This is one of the more unexpected results, and it is noted, though not explained, in the original reference [John-97]. Both of these papers, and references therein, note the general correlation between susceptibility to heavy ion induced latch-up with low LET threshold, and the sensitivity to proton-induced latch-up. The lack of a more quantitative correlation is blamed on the differences between charge deposition by heavy ions and proton-induced recoils and the associated charge collection processes [John-97]. For crude estimates, it is probably reasonable to assume that devices which exhibit a low heavy ion latch-up threshold (below 5 MeVcm2/mg) will also be sensitive to proton- IV-39 induced latch-up and even devices with LET thresholds of twice that may be suspect. The K5 example also illustrates that fabrication on a thin epitaxial starting material does not necessarily guard against latch-up, though systematic study of varying epi-layer thickness in one process has shown this to be an important step toward hardening against latch-up [LaBe-95]. Conversely, it is probably a safe assumption that if a device has been demonstrated to be hard or immune to latch-up by heavy ions then it will show similar hardness with respect to protons. Table 2: Measured and Calculated Proton SEL Cross Sections Device Measr'd BGR Calct'd Proton SEL Proton SEL marks X-Section, X-Section, HM65162 1.4E-10 1.4E-10 NEC-4464 1.8E-10 1.5E-10 6.6E-9 2.2E-11 t=6um 6.6E-9 t=2um LSI-64811 1.7E-11 6E-12 LCA200K 1.4-4.1E-11 7.6E-11 XC96002 4.5E-9 2.6E-10 t=6um XC96002 4.5E-9 8.8E-9 t=4um IDT3081 3E-11 0.9E-11 More detailed discussion of the present understanding of the mechanisms and modeling for proton-induced SEL can be fo