High Mobility IZTO Thin‐Film Transistors Based on Spinel Phase Formation at Low Temperature through a Catalytic Chemical Reaction

In this paper, In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) films with a single spinel phase are successfully grown at the low temperature of 300 °C through careful cation composition design and a catalytic chemical reaction. Thin‐film transistors (TFTs) with amorphous In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) channel layers have a reasonable mobility of 41.0 cm2 V−1 s−1 due to the synergic intercalation of In and Sn ions. In contrast, TFTs with polycrystalline spinel In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) channel layers, achieved through a metal‐induced crystallization at 300 °C, exhibit a remarkably high field‐effect mobility of ≈83.2 cm2 V−1 s−1 and excellent stability against external gate bias stress, which is attributed to the uniform formation of the highly ordered spinel phase. The relationships between cation composition, microstructure, and performance for the In2O3–ZnO–SnO2 ternary component system are investigated rigorously to attain in‐depth understanding of the roles of various crystalline phases, including spinel Zn2−ySn1−yIn2yO4 (y = 0.45), bixbyite In2−2xZnxInxO4 (x = 0.4), rutile SnO2, and a homologous compound of compound (ZnO)k(In2O3) (k = 5). This work concludes that the cubic spinel phase of Zn2−ySn1−yIn2yO4 (y = 0.45) film is a strong contender as a substitute for semiconducting polysilicon as a backplane channel ingredient for mobile active‐matrix organic light‐emitting diode displays. Single‐phase indium zinc tin oxide film with a spinel structure is grown by catalytic chemical reaction at 300 °C through a smart cation compositional design. The resulting transistor exhibits a remarkable high mobility of 83.2 cm2 V−1 s−1, excellent stability, and good uniformity. It can be applicable as an electrical switch to organic light‐emitting diode and memory devices.