Proton radiation hardness of single-nanowire transistors using robust organic gate nanodielectrics

In this contribution, the radiation tolerance of single ZnO nanowire field-effect transistors (NW-FETs) fabricated with a self-assembled superlattice (SAS) gate insulator is investigated and compared with that of ZnO NW-FETs fabricated with a 60 nm SiO ₂ gate insulator. A total-radiation dose study was performed using 10 MeV protons at doses of 5.71 and 285 krad(Si). The threshold voltage (V _th) of the SAS-based ZnO NW-FETs is not shifted significantly following irradiation at these doses. In contrast, V _th parameters of the SiO ₂-based ZnO NW-FETs display average shifts of ∼-4.0 and ∼-10.9 V for 5.71 and 285 krad(Si) H ⁺ irradiation, respectively. In addition, little change is observed in the subthreshold characteristics (off current, subthreshold slope) of the SAS-based ZnO NW-FETs following H ⁺ irradiation. These results strongly argue that the bulk oxide trap density and interface trap density formed within the SAS and/or at the SAS-ZnO NW interface during H+ irradiation are significantly lower than those for the corresponding SiO ₂ gate dielectrics. The radiation-robust SAS-based ZnO NW-FETs are thus promising candidates for future space-based applications in electronics and flexible displays.