Extensions of the FOM Method-proton SEL and atmospheric neutron SEU

The figure of merit (FOM) method developed by Petersen (1998) is extended in two different directions, to single-event latchup (SEL) by protons and to single-event upset (SEU) by atmospheric neutrons. In applying the FOM method to latchup, 30 different CMOS devices are examined, all with heavy ion SEL data, which are grouped into three categories based on whether they were tested with high energy protons/neutrons, and whether the protons also caused SEL. The plot of FOM as a function of the limiting proton SEL cross section leads to an empirically derived FOM value that serves as a screening criterion for whether devices with heavy ion SEL data are likely to be susceptible to proton SEL. By applying Petersen´s method to SEU from atmospheric neutrons, a simple relationship is derived for the SEU rate from these neutrons, and the variation of this rate with altitude and latitude is given.