SEU tolerance improvement in 22 nm UTBB FDSOI SRAM based on a simple 8T hardened cell
Abstract FDSOI technology has attracted considerable interests in space application due to its inherent high radiation resistance. An SEU hardened 8T SRAM cell is proposed and implemented in a test memory chip with advanced 22 nm UTBB FDSOI technology. Heavy ion experimental results show that the threshold LET of SEU for proposed 8T structure cell is up to ~24 MeV·cm2·mg−1 and less dependences of upset on data pattern and test modes are observed. Moreover, multiple bit upsets are not appeared in bitmap analysis results even under effective LET values at ~129 MeV·cm2·mg−1. The Pbb body biasing shows low influence on SEU rates in irradiation test, while the Nbb body biasing has ability to adjust the SEU sensitivity in a certain range. The error rate prediction indicates that this nanoscale FDSOI hardened SRAM is suitable for space application in harsh radiation environment.