Simulation of 14 MeV neutron-induced SEU in SRAM

Abstract

This paper presents a full-physical methodology to simulate single event upset (SEU) induced by 14 MeV neutron in static random access memory (SRAM). Nuclear-reaction simulator TALYS is first utilized to acquire valuable information about the secondary particles generated by nuclear interactions between 14 MeV neutrons with both silicon and oxygen nuclei. Based on Geant4 code, a tool named Gproton is used exclusively for the neutron/proton-induced SEU calculation. Pioneering Gproton simulation is used to output SEU candidate events by traditional critical-charge method and computing process is accelerated through a forced collision definition. Afterwards, a commercial TCAD which has good compatibility with the input and output files of the customized Gproton code is employed to distinguish the real SEU events from the candidate SEU events randomly selected. By combining Gproton and TCAD, a calibrated cross section of 14 MeV neutron-induced SEU can be obtained. The proposed method is applied to a 180-nm commercial SRAM with six-transistor memory cell. Predicted SEU cross section is in good agreement with experimentally measured value. The results present in this paper suggest that, for SRAMs exposed in 14 MeV neutron, the combination of the material particle transporting simulation and device TCAD modeling is a candidate method to provide reasonable predictions of the cross section of SEU which improves the accuracy of the prediction effectively.