Experimental Characterization and In-Flight Observation of Weakened Cell in SDRAM

SDRAM devices exposed to radiation environment are subject to Single Event Upset. In-flight observations and SEU characterizations highlight an increase of SEU sensitivity on SDRAM devices. This behavior is induced by a higher SEU occurrence on some addresses of the memories. This effect is observed as weakened cell generated by energetic particles on several addresses on the memory array. This study presents weakened cell observations on CARMEN and PICARD in flight missions that embedded two different SDRAM references. Behaviors of these two components have also been tested under Cobalt 60, protons and neutrons irradiation in order to try to reproduce the weakened cell effect on ground.