Simultaneous Extraction of Mobility Enhancement Factor and Threshold Voltage With Parasitic Resistances in Amorphous Oxide Semiconductor Thin-Film Transistors

This study presents a technique for simultaneous and consistent extraction of the mobility enhancement factor ( \gamma ) and the threshold voltage ( \textit{V}_{\textit{T}} ) with parasitic source and drain resistances ( \textit{R}_{\textit{S}} and \textit{R}_{\textit{D}} ) in amorphous oxide semiconductor (AOS) thin film transistors (TFTs). This technique allows for the extraction of \textit{R}_{\textit{S}} from \textit{R}_{\textit{D}} as well as the accurate extraction of \textit{V}_{\textit{T}} and \gamma with only \textit{I} - \textit{V} characteristics of the saturation operation in a single AOS TFT. The proposed technique was applied to amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs with various structures. For intentional asymmetry, we confirmed the consistency with an external resistor ( \textit{R}_{\text{ext}} = \text{10} , 20, 30 k \Omega ). Extracted parameters ( \textit{R}_{\textit{S}} , \textit{R}_{\textit{D}} , \textit{V}_{\textit{T}} , and \gamma ) by the proposed method were compared with parameters extracted by other methods for verification. Furthermore, the drain current ( \textit{I}_{\textit{D}} ) was well reproduced using the extracted parameters regardless of \textit{R}_{\text{ext}}