Comparison of the effects of ionizing radiation at twelve dose rates from 0.0015 to 100 rad(Si)/s

Abstract

Evidence is presented that two competing failure mechanisms exist in the Si-SiO2 system with one mechanism dominating at low dose rates and the other at high. Much lower dose failures than expected were discovered at low dose rates (<0.1 rad(Si)/s) and very low dose rates (∼0.001 rad(Si)/s) in commercial SGS 4007 CMOS devices. These failure doses plotted versus dose rate have a bell-shaped curve, rather than the expected straight line (decreasing with increasing dose rate), indicating that a different failure mechanism is dominant at low dose rates than at high.