Using Ti-doped GaZnO/InGaZnO/Ti-doped GaZnO sandwich composite Structure to enhance the device performances of transparent thin-film transistors
In this study, two transparent thin-film transistors (TFTs) with distinct channel designs were fabricated. The first was a single channel TFT (SC-TFT) with a typical 50-nm-thick amorphous indium-gallium-zinc oxide (a-IGZO) layer, and the second was a sandwich composite-channel TFT (CC-TFT) comprising three layers of 10-/30-/10-nm-thick Ti-doped GaZnO (GTZO)/a-IGZO/GTZO. In the CC-TFT, the bottom GTZO thin film in the composite channel exhibited a highly smooth surface, serving as a buffer template for superior IGZO channel layer thin-film growth. The studies of material quality indicated that the CC-TFT exhibited improved a-IGZO thin-film quality; relative to the SC-TFT, the oxygen vacancy concentration of the IGZO layer in the composite structure was reduced from 25.1% to 18.2% because of the adoption of a GTZO buffer layer. The CC-TFT demonstrated a high level of device performance, exhibiting an excellent field-effect mobility of 14.1 cm2/V-s, subthreshold swing of 0.33 V/decade, off current of 2.92 × 10−12 A, threshold voltage of 1.7 V, and on-off current ratio of 3.95 × 107.
The effects of high-energy electron beam irradiation on the properties of IGZO thin films prepared by rf magnetron sputtering
S. H. Jung, H. J. Moon, M. K. Ryu, K. I. Cho, B. S. Bae and E.-J. Yun* College of New IT Engineering, Hoseo University, Asan, Chungnam 336-795, Korea Department of Semiconductor and Display Engineering, Hoseo University, Asan, Chungnam 336-795, Korea Laboratory Oxide Electronics Research Team, ETRI, Daejeon 305-350, Korea Department of Semiconductor and Display Engineering and College of New IT Engineering, Hoseo University, Asan, Chungnam 336-795, Korea Department of Semiconductor and Display Engineering and Department of System Control Engineering, Hoseo University, Asan, Chungnam 336-795, Korea
Enhancement in electrical performance of indium gallium zinc oxide-based thin film transistors by low temperature thermal annealing
Abstract We have studied the characteristics of transparent bottom-gate thin film transistors (TFTs) using In–Ga–Zn–O (IGZO) as an active channel material. IGZO films were deposited on SiO 2 /Si substrates by DC sputtering techniques. Thereafter, the bottom-gate TFT devices were fabricated by depositing Ti/Au metal pads on IGZO films, where the channel length and width were defined to be 200 and 1000 μm, respectively. Post-metallization thermal annealing of the devices was carried out at 260, 280 and 300 °C in nitrogen ambient for 1 h. The devices annealed at 280 °C have shown better characteristics with enhanced field-effect mobility and high on–off current ratio. The compositional variation of IGZO films was also observed with different annealing temperatures.