Continuous Growth of Crystalline InGaZnO on InLaO by Spray Pyrolysis for High‐Performance Thin‐Film Transistors with Excellent Stability

Abstract

InGaZnO (IGZO) based thin film transistors (TFTs) are successfully employed in commercial displays due to their excellent electrical properties  but next‐generation displaybackplanes demand higher mobility. A heterojunction structure crystalline oxides can offer superior mobility and stability. Herein, the continuous growth of IGZO is reported on the crystalline InLaO (ILO) layer by spray pyrolysis, which closely resembles the crystalline structure of grown ILO layer. The crystalline structure of the IGZO is confirmed by grazing incidence X‐ray diffraction and high‐resolution transmission electron microscopy. The bilayer IGZO/ILO TFT exhibits remarkable electrical performance, including a high saturation mobility of 55.0 cm² V⁻¹ s⁻¹, low subthreshold swing of 110 mV dec⁻¹, and high I_ON/OFF ratio of ≈10⁹ with excellent stability under positive bias temperature stress with In addition, the inverter and ring oscillator based on the IGZO/ILO TFTs demonstrate a high voltage gain of 120 and a low propagation delay of 16.8 ns, respectively. The remarkable performance of bilayer IGZO/ILO TFT by spray pyrolysis is attributed to the In₂O₃‐like crystalline IGZO grown on ILO film. This leads to reduced lattice mismatch, resulting in minimizing grain boundaries and defects that can hinder electron transport at the interface. The matched crystal structure leads to efficient charge transport at the IGZO and ILO heterojunction, resulting in remarkable TFT performance.