THE EFFECT OF COSMIC-RAYS ON THE SOFT ERROR RATE OF A DRAM AT GROUND-LEVEL

This paper provides conclusive evidence that cosmic rays cause soft er rors in commercial dynamic RAM (DRAM) chips at ground level. Cosmic-ra y-induced soft errors in electronic components have long been a proble m for the designers of satellites and spacecraft, but they have not ge nerally been considered to be an important influence on memory chip so ft error rate (SER) in terrestrial environments. In an experiment desi gned to determine the effect of cosmic radiation on the SER of a sampl e of DRAM chips at ground level, the SER of a large number of chips wa s measured at various locations and altitudes around the US: near sea level in Essex Junction, VT; 200 m underground in a Kansas salt mine; at an altitude of 1.6 km in Boulder, CO; and at 3.1 km in Leadville, C O. The results reported here show that even at sea level there is a si gnificant component of the SER that can be attributed to the effects o f cosmic rays, and that the magnitude of the effects increases dramati cally at higher altitudes.