Extraction Method for Equivalent Oxide Thickness of a Thin High-κ Gate Insulator and Estimation of Field-Effect Mobility in Amorphous Oxide Semiconductor Nano-Sheet Junctionless Transistors

In this work, we have proposed an extraction method for equivalent oxide thickness (EOT) of a thin high-dielectric-constant ( $\kappa $ ) gate insulator (GI) through direct capacitance–voltage ( ${C}$ – ${V}$ ) measurements in amorphous indium tungsten oxide (a-IWO) nano-sheet (NS) junctionless (JL) transistors (a-IWO NS-JLTs). Without additional metal/insulator/Si-substrate (MIS) ${C}$ – ${V}$ measurements, the proposed extraction method can directly extract EOT (or equivalent $\kappa $ values) of a thin HfO ₂ GI at different ON-state gate voltages ( ${V}_{G}$ ) in a-IWO NS-JLTs. Results of ${C}$ – ${V}$ measurements show that the extracted EOT varies with ON-state ${V}_{G}$ owing to the gate-controllable conductance of the amorphous oxide semiconductor (AOS) NS channel. Finally, the extracted EOT can be used to estimate the field-effect mobility ( $\mu _{\text{FE}}$ ) of a-IWO NS-JLTs at different ON-state ${V}_{G}$ .