Enhanced Electrical Performance and Bias‐Stress Stability of Solution‐Processed Bilayer Metal Oxide Thin‐Film Transistors

Herein, solution‐processed indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) with a bilayer structure are investigated by embedding an ultrathin layer of indium zinc oxide (IZO) between the gate dielectric and IGZO film. The optimized IGZO/IZO bilayer TFTs exhibit a high field‐effect mobility (μFE) of 8.3 cm2 V−1 s−1, and the bias‐stress stability of the bilayer TFTs is greatly improved compared with that of the single‐layer IGZO devices. In addition, temperature‐dependent mobility and VT are investigated to reveal the trap distribution in the bilayer IGZO/IZO and single‐layer IGZO TFTs. Moreover, low‐voltage bilayer TFTs with a high mobility of 10.4 cm2 V−1 s−1 are demonstrated. Solution‐processed indium gallium zinc oxide/indium zinc oxide (IGZO/IZO) bilayer transistors show an enhanced electrical performance and bias‐stress stability compared with IGZO transistors. Furthermore, the underlying mechanisms are revealed from the energy diagram. High‐performance low‐voltage IGZO/IZO transistors based on Al2O3 high‐k dielectric are successfully demonstrated, showing great potential for low‐power electronics.