Charge Pumping Measurements of Radiation-Induced Interface-Trap Density in Floating-Body SOI FinFETs

We demonstrate that, by monitoring source and drain currents during alternating-current gate pulses, reliable estimates of radiation-induced interface-trap density can be obtained for conventional floating-body SOI FinFETs without body contacts. Estimates of effective interface-trap densities are shown for two development stage technologies, before irradiation, and for doses up to 1 Mrad(SiO₂). Straightforward estimates of effective interface-trap density are obtained for these floating-body FinFETs, with either a high-K or oxynitride gate dielectric, when the fin width is less than ~70 nm, the channel length is less than ~100 nm, and there is full gate control of the relevant interfaces. This modified charge pumping technique provides estimates of interface-trap density without detailed analysis, adjustable fitting parameters, and/or device simulation, in contrast to DCIV and/or gated-diode techniques. Moreover, this technique enables more accurate estimates of radiation-induced interface-trap density in floating-body FinFETs than midgap charge separation in cases for which isolation leakage contributes significantly to subthreshold current-voltage stretchout.