Gamma enhancement of proton-induced SEE cross section in a CMOS SRAM

CMOS SRAM parts (NEC 431000ACZ-70L) were tested for possible combined effects of gamma and proton irradiation. The parts were irradiated with a /sup 60/Co source to a variety of doses and at different dose rates. These parts were subsequently subjected to identical tests for proton-induced single-event effects (SEES). The cross section for proton-induced SEES increased with the prior /sup 60/Co dose and also showed an enhancement at lower dose rates.