Single Event Upset of Dynamic Rams by Neutrons and Protons

Dynamic 16K random access memories (RAMs) have been irradiated with neutrons having mean energies of 6.5, 9 and 14 MeV and with 32 MeV protons and have been found to undergo single event upset. For both particles, one upset is expected for approximately 108 particles/cm2. The upsets are statistical and the affected cells can be reset and continue normal operation. Both HIGH and LOW storage elements are upset though at different rates. The cause of the upsets is most probably a multi-MeV alpha particle created by an (n, alpha) or (p, alpha) or similar nuclear reaction. The alpha particle discharges either the storage capacitor, the floating bit line, or the reference capacitor used by the sense amplifier.