Solution processed low-voltage metal-oxide transistor by using TiO2/Li–Al2O3 stacked gate dielectric

A solution processed top-contact bottom-gated SnO2 thin-film transistor (TFT) has been fabricated using a TiO2/Li–Al2O3 bilayer stacked gate dielectric that show operating voltage of this TFT within 2.0 V. It is observed that the bilayer dielectric has much higher areal capacitance with lower leakage current density that significantly improve the overall device performance of TFT. The TFT with bilayer gate dielectric shows an effective carrier mobility (μsat) of 9.2 cm2 V−1 s−1 with an on/off ratio of 7.1 × 103 which are significantly higher with respect to the TFT with a single layer Li–Al2O3 gate dielectric. The origin of this improvement is due to the Schottky junction between the highly doped silicon (p++-Si) and TiO2 of bilayer stacked dielectric that induced electrons to the channel which reduces the dielectric/semiconductor interface trap-state. This investigation opens a new path to develop TFT device performance using a suitable bilayer stack of gate dielectric.