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 ( $\mu _{\mathrm {FEi}})$ 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 ( $V_{\mathrm {OV}})$ and temperature dependence of $\mu _{\mathrm {FEi}}$ . $\mu _{\mathrm {FEi}}$ extracted from the ZnON TFT decreases with an increase in $V_{\mathrm {OV}}$ and temperature, which suggests that the phonon scattering is the most probable mechanism limiting $\mu _{\mathrm {FEi}}$ in the ZnON TFT in the above-threshold region.