Thermal Response and DC/AC Performance of InGaZnO-Based Thin-Film Thermistors and Transistors on a Flexible Thin Glass Substrate

We report the fabrication of thermistors and thin-film transistors (TFTs), the crucial components and building blocks of sensor systems, on a transparent and flexible 100 μm-thin glass substrate. The thermal response of thermistors based on InGaZnO (IGZO) with Cu contacts exhibits an expected negative temperature coefficient of resistance of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\approx 1\%^{\circ}\mathrm{C}^{-1}$</tex> at temperatures between 25°C and 60°C. IGZO TFTs were realized with channel lengths as short as 6 μm, displaying a high on-off current ratio of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\approx 10^{9}$</tex> and an effective mobility of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7.3 \text{cm}^2 \mathrm{V}^{-1} \mathrm{s}^{-1}$</tex>. The AC performance of IGZO TFTs on flexible thin glass was also investigated for the first time resulting in a maximum oscillation frequency and transit frequency of up to 30.6 MHz and 10.4 MHz, respectively.