Contact resistance dependent scaling-down behavior of amorphous InGaZnO thin-film transistors

Here, we report scaling effects on the electrical properties of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFTs had same channel width/length ratio ( W/ L = 20), but different channel lengths ( L = 20, 10, 5, and 2.5 μm). To examine the scaling-down behaviors, short-channel effects and contact resistance of the TFTs were investigated. As the channel length decreased, apparent shift of threshold voltage ( V th) and degradation of subthreshold swing ( S SUB) were shown. In addition, it is also found that the field-effect mobility ( μ FE) was degraded as the channel length was decreased which was originated from contact resistance. Due to this contact resistance effect, drain current ( I DS) was decreased for short-channel devices. ► Scaling effects on the electrical properties of a-IGZO TFTs with same W/L ratio. ► Short-channel effects on the scaling-down a-IGZO TFTs. ► Effects of contact resistance on a-IGZO TFTs.