Transparent Ru–Si–O/In–Ga–Zn–O MESFETs on Flexible Polymer Substrates

With the development of novel device applications, e.g., in the field of Internet of Things or point-of-care personalized diagnostic systems, came an increased demand for MESFETs for fast and low-power consumption integrated circuits and active-matrix displays. In this paper, we present fabrication and characterization of transparent Ru–Si–O/In–Ga–Zn–O MESFETs on flexible substrates. The use of transparent conducting oxide, namely, Ru–Si–O, as Schottky gate electrode, allows for processing the devices at room temperature, enabling the utilization of such low-temperature substrates as polyethylene terephthalate foil and paper. It was shown that tuning the device geometry allows realization of transistors providing on-current up to 2 mA, while the highest on-to-off current ratio equals $2\times 10^{\mathrm { {5}}}$ , with off-current below 1 nA, carrier mobility in the channel exceeds 9 cm $^{\mathrm { {2}}}\cdot \text{V}^{\mathrm { {-1}}}\cdot \text{s}^{\mathrm { {-1}}}$ , and subthreshold swing is below 250 mV $\cdot $ decade $^{\mathrm { {-1}}}$ .