Ion Microbeam Probing of Sense Amplifiers to Analyze Single Event Upsets in a CMOS DRAM

Abstract

- By irradiating individual nodes of a CMOS DRAM composed of p-channel cells with a collimated microbeam of alpha particles, the relative sensitivity of circuit elements to single event upsets (SEU's) has been measured. The results show that alpha-particle hits on sensitive nodes within the sense amplifiers dominate the SEU rate. This domination is due to the presence in the sense amps of n-channel devices which can collect charge from the entire ion track. In contrast, the memory cells and bit lines contain only p⁺ nodes in an n-well, which shields them from charge generated in the substrate. © 1991 IEEE