Study on high-mobility and high-stability In 2 O 3 /Ga 2 O 3 heterojunction thin-film transistor

Abstract High-performance and electrically stable thin-film transistors (TFTs) are essential for advancing flexible and transparent electronics. While metal-oxide TFTs show great promise, the oxide channels often face performance and stability trade-off. In this work, we demonstrate a high-performance TFT utilizing a novel heterojunction (HJ) active layer composed of indium oxide (In 2 O 3 ) and gallium oxide (Ga 2 O 3 ). We report on the fabrication and characterization of TFTs with an In 2 O 3 /Ga 2 O 3 heterostructure channel to simultaneously achieve high mobility and operational stability. The In 2 O 3 /Ga 2 O 3 HJ was deposited by atomic layer deposition at 275 °C. The electrical properties and bias stress stability of the HJ TFTs were systematically investigated. The optimized In 2 O 3 /Ga 2 O 3 HJ TFT exhibits a high field-effect mobility ( μ FE ) of 95 cm 2 V −1 s −1 , a large I on / I off ratio of > 10 8 , and a steep subthreshold swing of 100 mV decade −1 . Remarkably, the device demonstrates exceptional stability, with a negligible threshold voltage shift (Δ V TH ) of only 0.05 V under positive bias stress (1 MV cm −1 , 1000 s) and −0.07 V under negative bias stress (−1 MV cm −1 , 1000 s). The device also shows good stability under high intensity illumination with Δ V TH of −0.36 V under positive bias illumination stress test (1 MV cm −1 , 1000 s, 10 000 lux) and Δ V TH of −0.76 V under negative bias illumination stress test (−1 MV cm −1 , 1000 s, 10 000 lux). These results underscore the great potential of the In 2 O 3 /Ga 2 O 3 HJ as a robust active layer for next-generation, high-performance oxide TFTs. This work provides a viable strategy using oxide HJs to overcome the limitations of conventional single-layer oxide TFTs.