Low-temperature, high-stability, flexible thin-film transistors with a novel ScxIn1−xO3 semiconductor

Abstract

Low-temperature scandium (Sc) incorporating In2O3 (ScxIn1−xO3) thin films as oxide semiconductors were developed and investigated. And flexible thin-film transistors (TFTs) based on ScxIn1−xO3 channel layers were fabricated on polyethylene naphthalate substrate with the highest process temperature of only 150 °C. The ScxIn1−xO3 TFT displayed high on/off ratio of 107 with a turn-on voltage (Von) of only −0.1 V, a subthreshold swing of 0.21 V dec−1, and a mobility of 17.5 cm2 V−1 s−1. Furthermore, the flexible ScxIn1−xO3 TFTs exhibit high stability under both positive bias stability and negative bias stability, which was ascribed to little change of the lattice parameter of In2O3 after incorporation with Sc (since the radius of Sc3+ is similar to that of In3+). More interestingly, the flexible ScxIn1−xO3 TFTs exhibited relatively good stability under negative bias illumination stability compared to those of IGZO TFTs, which was ascribed to fewer oxygen vacancies due to the strong bonding strength of Sc-O. Finally, the transfer curves of the ScxIn1−xO3 TFTs showed only a few changes under a curvature radius of larger than 20 mm.