High performance annealing-free thin-film transistors with 7-nm In0.72Ga0.28O/13-nm In0.46Ga0.54O homojunction channel

Abstract

Atomic layer deposition (ALD) enables the deposition of large-area, high-quality amorphous oxide semiconductor layers with precise control over film stoichiometry and thickness. In this study, homojunction thin-film transistors (TFTs) were fabricated using ALD. The homojunction structure consisted of a 7 nm thick In0.72Ga0.28O front channel layer and a 13 nm thick In0.46Ga0.54O back channel layer. By controlling In/Ga composition ratio and channel thickness, high performance field-effect transistors were fabricated at 200 °C without additional annealing. The transistor exhibited a mobility of 42.4 cm2 V−1 s−1, a conductive voltage near 0 V, a high Ion/Ioff ratio of 109, and a low subthreshold swing of 0.16 V/dec. Furthermore, compared to single-channel IGO devices, the homojunction dual-channel TFTs demonstrate superior performance in both bias stress stability and long-term stability.