Synergistic Approach to High-Performance Oxide Thin Film Transistors Using a Bilayer Channel Architecture

摘要

We report here a bilayer metal oxide thin film transistor concept (bMO TFT) where the channel has the structure: dielectric/ semiconducting indium oxide (In2O3) layer/semiconducting indium gallium oxide (IGO) layer. Both semiconducting layers are grown from solution via a low-temperature combustion process. The TFT mobilities of bottom-gate/top-contact bMO TFTs processed at T = 250 °C are —Stmex larger (～2.6 cm~2/(V s)) than those of single-layer IGO TFTs (～0.5 cm~2/(V s)), reaching values comparable to single-layer combustion-processed In2O3 TFTs (～3.2 cm~2/(V s)). More importantly, and unlike single-layer In2O3 TFTs, the threshold voltage of the bMO TFTs is ～0.0 V, and the current on/off ratio is significantly enhanced to —1 X 10~8 (vs ～1 X 10~4 for In2O3). The microstructure and morphology of the In2O3/IGO bilayers are analyzed by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy, revealing the polycrystalline nature of the In2O3 layer and the amorphous nature of the IGO layer. This work demonstrates that solution-processed metal oxides can be implemented in bilayer TFT architectures with significantly enhanced performance.