Dual Gate ZnO-Based Thin-Film Transistors Operating at 5 V: nor Gate Application

We report on the fabrication of ZnO-based dual gate (DG) thin-film transistors (TFTs) with 20-nm-thick $\hbox{Al}_{2}\hbox{O}_{3}$ for both top and bottom dielectrics, which were deposited by atomic layer deposition on glass substrates at 200 $^{ \circ}\hbox{C}$. As characterized with single gate (SG), DG, and ground plane (GP) modes, our ZnO TFTs are well operated under 5 V. DG-mode TFT showed a field mobility of 0.38 $ \hbox{cm}^{2}/\hbox{V} \cdot \hbox{s}$, a high saturation current of 6 $\mu\hbox{A}$, and an on/off current ratio of $\sim \hbox{10}^{6}$, while SG- and GP-mode TFTs showed a similar value of mobility but with lower current. Using DG and GP modes, nor gate operation was well demonstrated.