Muon-Induced Single-Event Upsets in 20-nm SRAMs: Comparative Characterization With Neutrons and Alpha Particles

Negative and positive muon-induced single-event upsets (SEUs) are studied in 20-nm bulk planar SRAMs. Muon irradiation is performed using a mono-energetic source with varying the muon energy. The energy dependence of the cross sections (CSs) of SEUs and multiple-cell upsets (MCUs) shows the significant contribution of muon capture reactions for the negative muon, as reported in previous studies. Interestingly, MCU events are found for the positive muon, in contrast to the previous studies. The CSs for the negative and positive muons are compared with that for the other terrestrial radiations: high-energy neutrons, thermal neutrons, and alpha particles. The voltage dependence of the SEU CS, together with the empirical model for charge collection, demonstrates the difference in the contributing secondary ions among the negative muon, the high-energy neutron, and the thermal neutron. The MCU events are thoroughly analyzed in terms of their ratio to the total events and their fail bit patterns. The results reveal that the MCU characteristics for the negative muon are different from that for the other terrestrial radiations due to the muon capture reactions, where parasitic bipolar effects and the isotropic emission of secondary ions are important factors.