Electron-Induced Upsets and Stuck Bits in SDRAMs in the Jovian Environment

This study investigates the response of synchronous dynamic random access memories to energetic electrons and especially the possibility of electrons to cause stuck bits in these memories. Three different memories with different node sizes (63, 72, and 110 nm) were tested. Electrons with energies between 6 and 200 MeV were used at RADiation Effects Facility (RADEF) in Jyvaskyla, Finland, and at Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments (VESPER) in The European Organization for Nuclear Research (CERN), Switzerland. Photon irradiation was also performed in Jyvaskyla. In these irradiation tests, stuck bits originating from electron-induced single-event effects (SEEs) were found, as well as single bit-flips from single electrons. To the best knowledge of the authors, this is the first time that stuck bits from single-electron events have been reported in the literature. It is argued in the article that the single-event bit-flips and stuck bits are caused by the same damage mechanism, which would be large displacement damage clusters, and that the two different fault modes represent different amounts of damage to the memory cell. After a large particle fluence, a rapid increase in the error rate was observed, originating from the accumulation of smaller displacement damage clusters in the memory cells. The 110-nm memory was a candidate component to fly on the European Space Agency (ESA) JUpiter ICy moons Explorer (JUICE) mission, so the SEE cross section as a function of electron energy was compared to the expected electron environment encountered by JUICE to estimate the error rates during the mission.

Automated summary

This study explores the impact of energetic electrons on synchronous dynamic random access memories, finding that single-electron events can cause stuck bits, a phenomenon reported for the first time in literature. Analysis suggests that single-event bit flips and stuck bits result from large displacement damage clusters, representing varying degrees of damage to memory cells. Furthermore, a rapid increase in error rate post high particle fluence is attributed to the accumulation of smaller displacement damage clusters.