Performance Variation According to Device Structure and the Source/Drain Metal Electrode of a-IGZO TFTs

The transmission-line method (TLM) was adopted to clarify the causes of device performance variation according to the source/drain metal electrode and device structure of a thin-film transistor using an amorphous indium-gallium-zinc-oxide channel. Using the TLM, the channel characteristics independent of contact resistance were extracted for the two different contact metals, i.e., Ti and Mo. Based on these results, the mobility characteristics were compared in terms of device scaling and contact structure in the source/drain overlap region. In addition, the transport characteristics according to the contact structure of the source/drain metal electrode were investigated in detail and reproduced using the simulation model.