Large-tilt Heavy Ions Induced SEU in Multiple Radiation Hardened 22 nm FDSOI SRAMs

Four kinds of radiation hardened SRAM were fabricated based on a 22 nm UTBB FDSOI process and irradiated by high-energy heavy ions. The high SEU tolerance and even SEU immunity for the three DICE SRAMs were investigated in vertical heavy-ion irradiation. However, the large-tilt-incidence (75°-85°) significantly increased the SEU cross sections for the 8-T SRAMs, and the errors in M-DICE and C-DICE hardened SRAMs in large tilt incidence were observed as well, indicating that the layout placement is essential. The UTBB FDSOI process contributes substantially to realize high SEU tolerance. While considering the existence of 4π-distributed relativistic heavy ions in space, the large-tilt irradiation is also indispensable in ground evaluation especially for the high reliable systems.