Improvement of Mobility and Stability in Oxide Thin-Film Transistors Using Triple-Stacked Structure

In this letter, amorphous indium-zinc-oxide thin film transistors (α-IZO TFTs) with a multilayered structure of an active layer were investigated by embedding a different indium-content layer: 1) the low-indium layer contacted with dielectric to reduce defect states and block off the drift of photoinduced holes and 2) the high indium layer to provide a conductive path with reducing scattering centers. In the multilayered structure, the α-IZO TFTs with high mobility and good photoinduced stability could be achieved. The fabricated TFT exhibited a field-effect mobility of 50.4 cm ² /Vs, which is thrice that of the single-layer device, an appropriate threshold voltage of 0.31 V, a low subthreshold swing of 0.14 V/decade, and a good negative bias illumination temperature stresses stability.