Highly ordered polycrystalline indium gallium oxide (PC-IGO) film is obtained by the crystallization of room temperature sputtered amorphous IGO on a hot plate at 350 °C for 1 h and then annealed for 1 h in an N2 O environment. A high-density PC-IGO of ≈7.15 g cm-3 with reduced oxygen vacancy (≈14.83%) and hydroxyl (OH) related defects (≈10.96%) has been obtained by N2 O annealing. Self-aligned coplanar thin-film transistor (TFT) with the PC-IGO exhibits the average saturation mobility of 78.73 cm2 V-1 s-1 , threshold voltage of -1.07 V, subthreshold swing of 0.147 V dec-1 , and the on/off current ratio of over 108 . The TFTs show excellent stability under bias-temperature stress with a negligible threshold voltage shift (ΔVTH ) of + 0.1 and -0.1 V for the positive and negative bias stresses, respectively. The TFTs exhibit very stable environmental stability when the TFTs are stored under high humidity (85%) and a high temperature (85 °C) for 2 days. The ring oscillator and the gate driver mode of the PC-IGO TFTs exhibit the propagation delay of 7.44 ns/stage with rising/falling times of less than 0.7 μs, respectively. Therefore, the PC-IGO TFTs are suitable for large area, high-resolution active-matrix organic, and inorganic light-emitting diodes displays.
Keywords: InGaO; high stability; hotplate crystallization; polycrystalline oxide; post-fabrication annealing; thin-film transistors.
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