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 (κ) 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 κ values) of a thin HfO2GI at different ON-state gate voltages (VG) in a-IWO NS-JLTs. Results of C - V measurements show that the extracted EOT varies with ON-state VG 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 (μFE) of a-IWO NS-JLTs at different ON-state VG.