Effect of annealing ambient on SnO₂ thin film transistors fabricated via an ethanol-based Sol-Gel route

The effect of annealing ambient on SnO₂ thin-film transistors (TFTs) fabricated via an ethanol-based sol-gel route was investigated. The annealing ambient has a significant effect on the structural characteristics and chemical composition and, in turn, the device performance. Although the crystalline-grain size of the SnO₂ films annealed in air was the smallest, this size yielded the highest field-effect mobility. Compared with the minimization of boundary scattering via crystalline-size increase, augmentation of the free carrier concentration played a more critical role in the realization of high-performance devices. The fabricated SnO₂ TFTs delivered a field-effect mobility, subthreshold swing, and on/off current ratio of 10.87 cm² /Vs, 0.87 V/decade, and 10⁷, respectively.