Low-Temperature ZrAlOx-PVP Hybrid Dielectrics with Crosslinking-Regulated Leakage Suppression for Flexible IGZO TFTs

Flexible oxide electronics require dielectric layers that combine low-temperature processability, low leakage current, high capacitance density, and mechanical reliability. In this work, we prepared ZrAlOx-PVP hybrid dielectric films through a low-temperature self-combustion solution process at 180 °C and systematically investigated the effect of PVP doping (0–2 wt%). The results show that PVP promotes the formation of M-O-C related bonding environments, suggesting the construction of an organic–inorganic crosslinked structure. Moderate PVP incorporation effectively suppresses leakage pathways, whereas excessive PVP induces polymer aggregation and trap-assisted conduction. Among all samples, the film on flexible PI (polyimide) with a PVP doping concentration of 0.5 wt% exhibits the best overall performance, with a leakage current as low as 1.89 × 10−8 A/cm2 at 1 MV/cm, a dielectric constant of 8.88. After static bending at a radius of 20 mm, the film maintains stable dielectric behavior, indicating improved stress tolerance. Flexible IGZO TFT fabricated with the optimized dielectric shows a mobility of 11.84 cm2 V−1 s−1, a threshold voltage of 0.48 V, and a subthreshold swing of 0.24 V dec−1 before bending. This work demonstrates that moderate PVP crosslinking provides an effective balance between defect suppression and stress relaxation, offering a practical interface-engineering strategy for low-temperature flexible high-k dielectrics.