Investigation of Carrier Transport Mechanism in High Mobility ZnON Thin-Film Transistors

Abstract

In this letter, the carrier transport mechanism in a high-mobility zinc oxynitride (ZnON) thin-film transistor (TFT) is investigated by analyzing the gate bias and temperature dependence of conductance and intrinsic field-effect mobility ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\mathrm {FEi}})$ </tex-math></inline-formula> in the subthreshold and above-threshold regions, respectively. The measured drain currents increase with a temperature and show a thermally activated Arrhenius-like behavior in the subthreshold region. The experimental results are well explained using a Meyer–Neldel rule, which suggests that the trap-limited conduction is the dominant carrier transport mechanism in the ZnON TFT in the subthreshold region. The carrier transport mechanism in the ZnON TFT in the above-threshold region is investigated by examining the gate overdrive voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm {OV}})$ </tex-math></inline-formula> and temperature dependence of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\mathrm {FEi}}$ </tex-math></inline-formula> . <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\mathrm {FEi}}$ </tex-math></inline-formula> extracted from the ZnON TFT decreases with an increase in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm {OV}}$ </tex-math></inline-formula> and temperature, which suggests that the phonon scattering is the most probable mechanism limiting <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\mathrm {FEi}}$ </tex-math></inline-formula> in the ZnON TFT in the above-threshold region.