Crystallization of 1 μm Unit‐Width, Well‐Aligned a‐IGO in Parallel for Flexible Thin‐Film Transistors Exhibiting Mobility Over 100 cm 2  V −1  s −1

ABSTRACT We report high‐performance, polycrystalline indium–gallium–oxide (poly‐IGO) thin‐film transistors (TFTs) based on an active split structure with 1 μm unit‐width channels. The self‐aligned, coplanar TFT fabricated on polyimide (PI) substrate exhibits threshold voltage (V TH ) of +0.9 V, saturation mobility (μ SAT ) of 108.8 cm 2 V −1 s −1 , and subthreshold swing of 0.28 V decade −1 . After patterning amorphous IGO (a‐IGO) layer into 1‐μm‐wide parallel units, the crystallization was carried out at 450 °C. The resulting poly‐IGO film shows well‐aligned (222)‐dominant crystalline domains along the edge regions. The TFT shows a small hysteresis window (V H ) of +0.07 V. Upon detaching the TFTs on PI substrate from the carrier glass, no degradation in TFT performance was observed, confirming the mechanical reliability of the active split TFTs. The TFTs maintain stable electrical performance under compressive bending with bending radius down to 1 mm and endure up to 10,000 in‐folding cycles without V TH shift. These results demonstrate that the 1 μm unit‐width active‐split poly‐IGO TFTs enable high electrical performance and outstanding mechanical reliability, offering strong potential for next‐generation flexible oxide TFT electronics.