Simulation of a-IGZO TFT Device Using Finite Element Method

This work uses the COMSOL Multiphysics simulation tool to analyse the effect on the transfer characteristics of an amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFT) due to varying some parameters such as active channel thickness, doping concentration, gate dielectric thickness, and metal electrodes work function (4.2-4.5 eV). We demonstrated that when the thickness of the a-IGZO active layer, gate oxide, and doping concentration increases, the threshold voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf>) decreases. The subthreshold swing (SS) and threshold voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf>) are the functions of channel layer thickness and gate oxide thickness. Also, we demonstrated the linear shift in threshold voltage due to varying surface charge on the a-IGZO active layer. This ability makes it an ideal choice for sensing applications.