A Study of Parasitic Series Resistance Components in In–Ga–Zn–Oxide (a-IGZO) Thin-Film Transistors

We extracted the effective channel length and parasitic series resistance in a-IGZO inverted-staggered etch-stop (ES) TFTs. When there is an overlap between the drain or source electrode and the FET channel, the resistance of the channel underneath the overlapping regions is very low compared with other channel region resistance. As a result, the effective channel length is smaller than the physical length. The aforementioned definition of effective channel length in terms of device geometric parameters seems to be specific for ES a-IGZO TFTs.