Novel Gated-Multiprobe Method for Measuring a Back Electrode Effect in Amorphous Oxide-Based Thin-Film Transistors

In this paper, we investigated the variations in electrical characteristics of amorphous indium-gallium-zinc-oxide thin-film transistors using a gated-multiprobe method when additional probe electrodes are on the back-channel region. We found that the resistance of the probe region is much smaller than that of the nonprobe region, which can be modeled by a series connection of transistors and resistors indicating that the probe region is independent of V_GS and induces a decrease in effective channel length. We also performed technology computer aided design (TCAD) simulations and found that the effective channel length decreases and drain current increases, which is consistent with the experiments.