Memory reliability of spintronic materials and devices for disaster-resilient computing against radiation-induced bit flips on the ground

The memory reliability of magnetic tunnel junctions has been examined from the aspect of their potential use in disaster-resilient computing. This computing technology requires memories that can keep stored information intact even in power-cut emergency situations. Such a requirement has been quantified as a score of acceptable flip probability, which is the failure in time (FIT) rate of 1 for a single-interface perpendicular magnetic tunnel junction (p-MTJ) with a disk diameter of 20 nm. For comparison with this acceptable probability, p-MTJ memory reliability has been evaluated. The risk of particle radiation bombardments, i.e., alpha particles and neutrons-the well-known soft error sources on the ground-has been evaluated from the aspects of both frequency of bombardments and the hazardous effects of bombardments. This study highlights that highenergy terrestrial neutrons may lead to soft errors in p-MTJs, but the flip probability, or the risk, is expected to be lower than 1 ' 10%6 FIT/p-MTJ, which is much smaller than the target probability. It has also been found that the use of p-MTJs can reduce the risk by three orders of magnitude compared with that of the conventional SRAMs. Few risks have been suggested for other radiation particles, such as alpha particles and thermal neutrons.