High-performance InSnO tunneling contact transistors via oxygen partial pressure modulation

Thin-film transistors with a source barrier—such as source-gated transistors and tunneling contact transistors—exhibit ultrahigh intrinsic gain (Ai) and low power consumption, making them promising candidates for low-power circuits and wearable devices. However, their low output saturation current (Idsat) remains a significant challenge. In this work, tunneling contact thin-film transistors (TC-TFTs) with a high-mobility indium tin oxide (InSnO) channel were fabricated, and the effect of oxygen partial pressure on their performance was systematically investigated. Compared to conventional InSnO transistors, InSnO TC-TFTs demonstrated a significant increase in intrinsic gain and a reduction in power consumption. Furthermore, by adjusting the oxygen partial pressure during the sputtering of InSnO, the output current of the TC-TFTs was improved to a level comparable to that of conventional InSnO transistors. X-ray photoelectron spectroscopy analysis revealed that the output current's dependence on oxygen partial pressure is attributable to variations in Schottky barrier height, which are induced by changes in carrier concentration. These results demonstrate the potential for fabricating high-performance InSnO TC-TFTs that combine large saturation current, high intrinsic gain, and low power consumption.