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
Economics of General-Purpose Assembly Robots
Summary A study of the comparative economics of various automatic assembly systems using general-purpose assembly robots is described. In the study, use is made of a “typical” candidate assembly whose profile is obtained from statistical analysis of actual products submitted by interested companies. It is shown that the choice of assembly system and the various parts presentation methods depends on three main factors, namely: the annual production volume per shift, the number of parts in the product and the equipment payback period.