Effect of In-Ga-Zn-O active layer channel composition on process temperature for flexible oxide thin-film transistors

In-Ga-Zn-O (IGZO)-channel oxide thin-film transistors (TFTs) were fabricated on flexible polyethylene naphthalate (PEN) substrates. A lamination and delamination procedure was established that allowed easy handling of the PEN substrate during fabrication. In order to fabricate high-performance flexible IGZO TFTs at lower than normal process temperatures, a 2:1:2 (In:Ga:Zn) IGZO channel composition was proposed. The field-effect mobility, threshold voltage, and subthreshold swing of the fabricated IGZO TFTs were found to be approximately 7.83 cm2 V−1 s−1, 1.93 V, and 0.24 V/decade, respectively, even when a final heat treatment was conducted at a temperature as low as 150 °C. The stability characteristics of the devices were also examined under gate bias stress and constant current stress conditions.