Cosmic ray induced soft error rate in VLSI circuits

The Monte Carlo methods originally developed for obtaining α-particle-induced soft error rates (SER's) have been extended to calculate soft errors caused by cosmic rays. Specifically, the effects of the sea level cosmic ray spectrum is calculated for a representative VLSI DRAM. The results show that the effects of sea level cosmic rays are minor when compared to the soft error rate caused by even moderate amounts of local radioactive contamination. At the same time, the precise cosmic soft error rate given here sets a limit on the possible reduction of the overall soft error rates by all hardware solution, including material purification.