Scaling Benefits for Active and Gate Insulator of Vertical Channel Thin-Film Transistors Using Atomic Layer Deposited InGaZnO Channel

In-Ga-Zn-O (IGZO) vertical-channel thin-film transistors (VTFTs) were fabricated with thickness scaling of the channel ( ${T}_{\textit {CH}}{)}$ and gate insulator ( ${T}_{\textit {GI}}{)}$ . The channel bulk trap densities of the VTFTs were estimated to be 40 times larger than those of conventional TFTs due to the rugged back channel. The effects of bulk defects could be minimized by scaling down the ${T}_{\textit {CH}}$ and ${T}_{\textit {GI}}$ to 5 and 15 nm, respectively; hence, the IGZO VTFT exhibited a steep slope of 95 mV/dec and a high current drivability of $56.4~\mu \text{A} / \mu \text{m}$ .