Total Ionizing Dose Responses of 22-nm FDSOI and 14-nm Bulk FinFET Charge-Trap Transistors

Abstract

Total-ionizing-dose (TID) effects are investigated for 22-nm fully-depleted silicon-on-insulator (FDSOI) and 14-nm bulk FinFET charge-trap memory transistors. Electron trapping in the gate dielectric establishes the programmed memory state for both silicon on insulator (SOI) and bulk devices. To first order, ionizing radiation does not interact strongly with programing-induced charges in the gate dielectric for either device type. Hole trapping in the buried oxide dominates the TID response of the 22-nm FDSOI devices. The 14-nm bulk devices with two fins and total effective fin widths of 150 nm are minimally affected by TID, but the subthreshold leakage of devices with 40 fins and total effective fin widths of 3 μm increases with increasing TID. When devices are programmed or reprogrammed after irradiation, significant increases in subthreshold slope are observed due to the generation of interface traps, border traps, and/or charge lateral nonuniformities.