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 × 10
⁵
, with off-current below 1 nA, carrier mobility in the channel exceeds 9 cm
²
·V
^-1
·s
^-1
, and subthreshold swing is below 250 mV·decade
^-1
.