Applications of a Microbeam to the Problem of Soft Upsets in Integrated Circuit Memories

The charge from electron-hole pairs, produced by the passage of a charged particle, may be sufficiently large to alter the stored information in modern dynamic random access memories (dRAMs), thus producing a soft upset. A microbeam from a 5-MV Van de Graaff has been used to investigate the upset process in 64K dRAMs. The microbeam has also been used to investigate the related problem of charge collection by small MOS structures and its dependence on gate oxide thickness. A model relating the charge observed in the external circuit to the charge collected internally has been developed.