New Concerns on Heavy Ion Irradiation Induced Variation Degradation in Nanoscale CMOS Devices

The impact of heavy ion irradiation on the variability of 65 nm bulk Si MOSFETs is experimentally demonstrated in this brief. Due to the intrinsic random incidence of heavy ions, additional variability is introduced in the irradiated devices through displacement damage (DD) and microdose effects. For the smallest size devices, the standard deviation of threshold voltage ( V
_th
) of irradiated devices is up to ~10% larger than fresh devices. The geometry dependence of irradiation-induced variation degradation is illustrated. The irradiation-induced variation degradation increases with decreasing gate width AND/OR gate length, which is attributed to the irradiation-induced ionization damage fluctuation in the shallow trench isolation (STI) and spacer, respectively. The Pelgrom plot is used to quantify the irradiation-induced variation degradation. After irradiation, the slopes of fitting lines in Pelgrom plots of nMOS and pMOS devices are 10.3% and 5.7% larger, respectively. The results highlight the heavy-ion-induced variation degradation in the nanoscale CMOS devices, which bring new concerns on the design of integrated circuit (IC) for aerospace applications.