Simulation of Different SRAM Cells under Neutron Radiation with GEANT4

The simulation tool GEANT4 is used for the simulation of particle interaction under radiation exposure. In this investigation the tool is used to calculate the interaction of neutrons in the SRAM cells in the active means transistor region of the cells. The goal is to determine the sensitivity to bit flips. The determination of the linear energy transfer (LET) depending on the count of transistors and cell size was investigated. The investigated SRAM-cells were fabricated in a 180nm node. The neutron radiation energy which may lead to a single event upset (SEU) was determined. The simulation was carried out with different particle energies of 1.6MeV, 2.45MeV, 6MeV and 14MeV. Threshold energies are necessary to initiate a bit flip. With the help of the simulation, the energy transfer into the active region can be determined. As a result, the adaptation of measurement (radiation time and dose) can be done.