Background: The failure phenomenon is difficult to analyze for the flash memories when the whole chip is exposed to irradiation since both the memory array and the peripheral circuits might be degraded.Purpose: In order to detect the radiation susceptibility and corresponding phenomenon of the related circuits that included in the flash memories

the X-ray microbeam is used as the radiation source instead of 60 Co.Methods: The failure phenomenon is studied respectively when the memory array

decoder circuits

the charge pump circuits as well as the I/O circuits are exposed to radiation.The errors are mapped according to the logical address and the failure mechanism is analyzed based on the circuits.Results: Irradiated on the memory array will lead to regularly distributed 0→1 bit flips

while only 1→0 are found when the row decoder is under exposure.Degradation of the charge pump circuits would lead to the erase/program functional failure.Conclusions: The results suggest that the X-ray microbeam radiation test is a good method for detecting the radiation susceptibility of the integrated circuits that contains lots of circuit modules.