large-area processability to achieve high carrier mobility with ultra-low off-currents, and very smooth surface, opening a wide window as an active semiconductor layer for the active-matrix (AM) transparent and flexible electronics. [1] Especially, indium oxide (In 2 O 3 ) based materials with the addition of zinc oxide (ZnO), gallium oxide (Ga 2 O 3 ), and tin oxide (SnO 2 ) are widely investigated for a TFT channel semiconductor for active-matrix organic light-emitting diode (AMOLED) technology. [2][3][4][5] Among them, amorphous InGaZnO (a-IGZO) becomes an industrial standard for display backplane technology. [4] But, the key issue of a-IGZO is its limited mobility because of its material disorder in the amorphous state. [4] In the hexagonal IGZO materials, crystallization of room-temperature (RT) deposited amorphous IGZO can be possible by high-temperature annealing over 700 °C. [6] On the other hand, by raising both the deposition temperature and oxygen partial pressure, a crystalline IGZO with a C axis aligned crystal orientation (CAAC-IGZO), can be obtained. It exhibits some unique properties in terms of performance such as ultra-low off-state current, close to ideal subthreshold swing (SS) because of the absence of minority carriers, which can differentiate them from the amorphous one. By having well defined CAAC crystal structure it is possible to achieve excellent TFT performance compared to the randomly orientated IGZO crystallites. The maximum reported mobility is 65.5 cm 2 V −1 s −1 for a sputtered coplanar CAAC-IGZO with a dual-gate structure. [7] Several TFT structures are investigated including back-channel etched (BCE), etch stopper inverted staggered, and self-aligned coplanar, however, the coplanar structure has the advantage of having the minimum overlap parasitic capacitance which is suitable for the large area, AMOLED displays.The requirement for a high drain current with high mobility TFT is increasing for large area, high-resolution displays. Crystalline oxide is being studied to overcome the mobility issue associated with the amorphous phase. Among them, crystalline In 2 O 3 is known as the wide bandgap (≈3.7 eV), highly 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 N 2 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 N 2 O annealing. Self-aligned coplanar thin-film transistor (TFT) with the PC-IGO exhibits the average saturation mobility of 78.73 cm 2 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 10 8 . The TFTs show excellent stability under bias-temperature stress with a negligible threshold voltage shift (ΔV TH ) of + 0.1 and -0.1 V for the positive and negative bias stresses, respectively. The TFTs exhibit very stable environmental stability when...