"Continued Exploration of the Neutron Single Event Upset Sensitivity of Current Generations (90 nm and 65 nm) of Field Programmable Gate Arrays"
Joe Fabula, Austin Lesea, and Ray Matteis
Radiation results have previously been published  detailing several real-time experiments (Rosetta) that evaluated the configuration latches and memory storage blocks utilized in large Field Programmable Gate Arrays (FPGAs) fabricated in different CMOS technologies (0.15µ, 0.13µ and 90 nanometer) for their sensitivity to atmospheric neutron radiation induced single-event upsets. The results were compared to circuit simulation (Q-crit) studies, as well as to LANSCE neutron beam results and Crocker Nuclear Laboratory (U. C. Davis) cyclotron proton beam results. The simple Q-crit simulations were shown to be inadequate for designing robust structures to these effects.
The latest data from two additional 90 nanometer technology studies performed on commercially available FPGAs (possibly data on 65 nm structures will be included) have shown the simulation techniques used to be flawed, but more importantly have also shown that normal acceleration calculations commonly applied to neutron beam testing are not accurately predicting the real improvements that are being realized in the atmospheric testing of today’s integrated circuits. This paper will address some of the issues with the common neutron energy distribution models utilized for such projections, will discuss alternative models, and will examine their efficacy in predicting the results seen in the atmospheric testing. If time permits, the results of “time of flight” experiments performed at LANSCE examining the sensitivity of various technologies to specific portions of the neutron spectrum will be detailed to support these contentions.
1. Austin Lesea, Saar Drimer, Joseph Fabula, Carl Carmichael, and Peter Alfke, The Rosetta Experiment: Atmospheric Soft Error Rate Testing in Differing Technology FPGAs. IEEE Transactions on Device and Materials Reliability, Vol. 5, Number 3, September, 2005.
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