Similarities and differences of irradiation effects between floating gate ROMs (Read Only Memory) and SRAM (Static Random Access Memory) are compared.Reasons for differences are analyzed.The 14MeV neutron fluence threshold when error occurs in floating gate ROMs is higher than that in SRAM by 5 orders of magnitude

31.9MeV proton fluence threshold by 4 orders

and total dose threshold is about 10

4

rad(Si) for both memories.All of these are attributed to the structure of memory cells and mechanism of radiation effects.Floating gate ROMs are preferable to SRAM in application in space radiation environment when data in memory are not required to erase and write frequently.