Modelling and numerical analysis for wavy edge in printed source and drain electrodes of thin-film transistors

The wavy edge in printed narrow line electrodes is modelled by using a sequence of semi-ellipses and its effect on the electrical performance of a hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) when the wavy patterns exist in its printed source and drain (S/D) electrodes is analysed. Based on ATLAS 3D simulation, it is found that peak-to-peak magnitude of the S/D wavy edge had large, period had small, and phase shift between S/D wavy patterns had negligible effects on the TFT performance change. A transmission line method was used to explain the S/D wavy edge effect in terms of an increase of the effective channel length.