Oxygen Vacancy Passivation by Compensation Technique to Address the Conflict Between Mobility and Threshold Voltage of Heterojunction Oxide Transistors

Oxide transistors have attracted considerable attention in integrated circuits and practical applications, yet they face the fundamental conflict between field‐effect mobility ( μ FE ) and threshold voltage ( V th ). In this study, we propose a compensation technique that can effectively passivate oxygen vacancies and enhance the gate control capability of devices, achieving a balance between the μ FE and V th of InZnO/ZnO heterojunction transistors. After treating the back‐channel region with 0.05 mol L −1 –NH 4 Cl solution for 30 s, V th exhibits a positive shift from −1.51 to −0.75 V, accompanied by a reduction in subthreshold swing (SS) from 246.50 to 96.90 mV dec −1 . The μ FE remains at a high level from 71.63 to 70.60 cm 2 V −1 s −1 . Ultraviolet photoelectron spectroscopy (UPS) and X‐ray photoelectron spectroscopy (XPS) analyses reveal that this method reduces the oxygen vacancy on the channel surface. Density functional theory (DFT) reveals that OH groups from the solution passivate oxygen vacancies via Zn–H–Zn bridges intermediate, forming Zn–OH as the final product at room temperature. Inverters based on treated InZnO/ZnO transistors were fabricated, exhibiting a fivefold enhancement in gain from 90 to 450 V/V. This electrical compensation strategy features low‐temperature operation, low power consumption, and large‐area processability, demonstrating great potential for back‐end‐of‐line integration applications.