Impact of bias stability for crystalline InZnO thin-film transistors

Crystallized InZnO thin-film transistors (IZO TFTs) are investigated to identify a potential for the maintenance of high electrical performances with a consistent stability. The transition from an amorphous to a crystallization structure appeared at an annealing temperature around 800 °C, and it was observed using transmission electron microscopy and time-of-flight secondary ion mass spectrometry analysis. The field-effect mobility of the crystallized IZO TFTs was boosted up to 53.58 cm²/V s compared with the 11.79 cm²/V s of the amorphous devices, and the bias stability under the negative stress was greatly enhanced even under illumination. The defect states related to the oxygen vacancy near the conduction band edge decreased after the crystallization, which is a form of electrical structure evidence for the reliability impact regarding the crystallized IZO TFTs.