Low-temperature pressure-assisted liquid-metal printing for β-Ga2O3 thin-film transistors

Abstract

Developing a low-temperature and cost-effective manufacturing process for energy-efficient and high-performance oxide-thin-film transistors (TFTs) is a crucial step toward advancing next-generation device applications such as wearable and flexible electronics. Among several methods, a liquid-metal printing technique is considered a promising, cost-effective oxide semiconductor process due to its inherent advantages, such as vacuum-free, low-thermal budget, high throughput, and scalability. In this study, we have developed a pressure-assisted liquid-metal printing technique enabling the low-temperature synthesis of polycrystalline wide bandgap n-channel oxide-TFTs. The n-channel oxide TFTs based on ~3 nm-thick β-Ga₂O₃ channels exhibited good TFT switching properties with a threshold voltage of ~3.8 V, a saturation mobility of ~11.7 cm² V⁻¹ s⁻¹, an on/off-current ratio of ~10⁹, and a subthreshold slope of ~163 mV/decade. We also observed p-channel operation in the off-stoichiometric GaO_x channels fabricated at high-pressure conditions. Toward oxide-based circuit applications, we developed high-performance oxide-TFT-based inverters. While our approach can promote the advancement of low-temperature manufacturing for oxide TFT technology, further work will be necessary to confirm the role of the applied pressure in the β-Ga₂O₃ crystallization process.