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Total-ionizing-dose (TID) effects are investigated in a highly-scaled gate-all-around (GAA) FET technology using Si nanowire channels with a diameter of 8 nm. n- and p-FETs are irradiated up to 300 Mrad(SiO2) and annealed at room temperature. TID effects are negligible up to 10 Mrad(SiO2). At ultrahigh doses, the TID degradation depends on the irradiation bias condition, with more severe effects observed in longer channel devices. The worst case irradiation condition is when positive bias is applied to the gate. Threshold-voltage shifts are caused by H+-driven generation of interface traps at the oxide/channel interface. In contrast, FETs irradiated under negative gate bias are dominated by transconductance loss and increases of low-frequency noise, suggesting the activation of border traps. Enhanced off-leakage current is observed in n-FETs due to charge trapping in shallow-trench isolation, and in p-FETs due to trap-assisted recombination at STI sidewalls and/or spacer dielectrics at drain/bulk junctions. [ABSTRACT FROM AUTHOR]

Negative-bias-stress and total-ionizing-dose (TID) effects in deeply scaled Ge-gate-all-around (GAA) nanowire (NW) devices are characterized for different biasing conditions. Negative-bias-stress-induced degradation in Ge GAA device originates primarily from the interface- and border-trap generation. Devices stressed at high gate voltage show rapid initial degradation and quick saturation dominated by interface-trap generation. Radiation-induced OFF-state leakage current in Ge GAA NWs increases with dose due to enhanced band-to-band tunneling (BTBT) caused by charge trapping in the shallow trench isolation (STI). [ABSTRACT FROM AUTHOR]