Numerical Simulation on Thickness Dependency and Bias Stress Test of Ultrathin IGZO Thin‐Film Transistors Via a Solution Process

Abstract

The authors report the effect of ultra‐thin channel layer thickness on the performance of an amorphous InGaZnO (a‐IGZO) thin‐film transistor (TFT). Numerical simulation is used to investigate the thickness effect on the a‐IGZO TFT output parameters. The simulation results are compared to measurements of the stability of nitrate ligand‐based hexaaqua complexes solution‐processed ultrathin a‐IGZO transistors a‐IGZO. This TFT is also tested under negative illumination bias stress (NIBS) and positive bias stress (PBS). The thinner channel layer is found to have a better performance than the thicker channel layer. The 4 nm‐thick, ultra‐thin a‐IGZO TFT exhibits high saturation mobility (7.56 cm2 V−1 s−1), low threshold voltage (2.73 V), a small value of sub threshold swing (0.22 V dec−1), and a high on/off ratio (). It is also noticed that the threshold voltage (Vth) shifts negatively as the thickness increases. The 4 nm long channel TFT shows more stability under NIBS and PBS while 16 nm have a strong degradation under NIBS and PBS.