Mutual interference induced by single event effects in CMOS circuits

Single event effect (SEE) induced mutual interference in CMOS circuits, including single event (SE) induced coupling effects (crosstalk) and modulation in local supply voltage on power-supply rails, was studied based on the increase in metal interconnect density. The dependence of SE vulnerability on metal interconnects was experimentally investigated using heavy ions and pulsed laser. Numerical simulation was performed to evaluate the modulation in local supply voltage induced by SEEs. Two groups of test structures with various metal interconnects between well contacts and the first metal layer were designed and fabricated. All other parts, including well contacts in the active regions, are of the same structures. Experimental results show that the upset cross section decreases with an increase in metal interconnect contact (CT) density between the active region and the first metal layer, suggesting a dominant contribution of rail voltage drop induced by charge sharing rather than SE-induced crosstalk. The differences in upset cross sections with cells of different CT hole densities appear the most evident ones under low frequency and high linear energy transfer value conditions. When transient-induced upsets play a more important role, the differences get weakened due to masking effects.