Study of Local Band Bending in -Channel InO Thin-Film Transistors under Gate and Drain Voltage Stress Using Hard X-ray Photoelectron Spectroscopy.

In this study, we analyze InO thin-film transistors (InO-TFT) using synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES) in conditions. A bottom-gate InO-TFT with a high- AlO gate dielectric, grown on thermally oxidized silicon (SiO/p-Si), was examined while operating at varying and . The results reveal that the In 3d core level binding energy varies along the horizontal channel length, driven by the potential gradient induced by . Furthermore, the polarity of under positive significantly affects the channel structure, and influences the vertical electrostatic potential in the buried gate dielectric and the gate electrode. Analysis suggests that the primary source of drain-source leakage current () arises from high intrinsic electron and defect/trap levels associated with oxygen vacancies (). Additionally, investigation beneath the Au/Ti drain and source electrodes under different bias voltages reveals substantial InO reduction, leading to significant indium metal (In) formation. Schematic models of carrier transport mechanisms are proposed to explain these findings.