Incorporation of Secondary-Ion Information and TCAD Simulation for Atmospheric Neutron Soft-Error-Rate Prediction in SRAMs

Neutron-induced secondary ions and their contribution to a single-event upset (SEU) in SRAM are investigated by Geant4 and TCAD simulations. It proves that the maximum linear energy transfer (LET) values of secondary ions produced by neutron-nuclear reactions can be as high as 31.5 MeV-cm
²
/mg, while the LET value of 99.8% secondary ion is <; 16 MeV-cm
²
/mg. Only the secondary ion with the LET of >2 MeV-cm
²
/mg could induce an SEU in this 65-nm SRAM. Then, these results are used to calculate the atmospheric neutron-induced soft-error rate (SER). The calculated SER is verified by field testing and 14-MeV neutron-accelerated testing.