SEU-Induced Bitflips of 7-Series FPGA Under Fast Neutron Irradiation

Abstract

Radiation-induced soft errors from single event effects (SEEs), such as single event transients (SETs) and single event upsets (SEUs), can cause bitflips or faults, potentially leading to data corruption or system failure in safety critical applications if unmitigated. In this work, we discuss a methodology for evaluating soft errors introduced by SEEs and characterizing the radiation upset sensitivity of 7-series static random access memory (SRAM)-based field programmable gate arrays (FPGAs) in the context of nuclear power plant (NPP) instrumentation and control (I and C) applications. A cross-sectional error model was developed using fast neutron irradiation experiments, which informs statistical models for error probabilities of bitflips in the target FPGA device. Fuzz testing was used to correlate the bitstream structure to the physical on-board location of configurable logic blocks (CLBs), programmable interconnect points (PIPs), and digital signal processing (DSP) tiles. The cross section for SEU-induced bitflips in the tested SRAM-FPGA for ~2-MeV neutrons was estimated as $1.68\times 10^{-15}~$ cm²/bit from reactor neutron irradiation experiments. The tile type with the largest tile-normalized cross section was determined as a look-up table (LUT) at $4.06\times 10^{-15}~$ cm²/bit, and the tile type with the largest bitstream-normalized cross section was found to be INT at $9.50\times 10^{-16}~$ cm²/bit, with uncertainty intervals overlapping those of other resource types.