Fabrication and Characterization of a-IGZO Thin-Film Transistors With and Without Passivation Layers

Abstract

The thin-film transistors (TFTs) devices based on amorphous indium gallium zinc oxide (a-InGaZnO, a-IGZO) films were fabricated and characterized in this paper. We have employed the a-IGZO thin film as an active channel layer in the bottom gate structure of transistor, the silicon dioxide (SiO2) as a gate insulator, and the indium tin oxide (ITO) as a gate source and drain electrodes. All of them were grown on ITO glass substrates by radio frequency (RF) magnetron sputtering technique. However, there were still some inherent defects in the a-IGZO materials, it would be affected the performance of the fabricated transistors. Therefore, in this work, it explored to research a-IGZO TFTs with aluminum (Al) passivation layers as sensitive to water and oxygen thereby affect the device stability, and time dependence threshold voltage variation in ambient of passivation layer and reliability. Demonstrably, our experimental results revealed that the W/L (W = wide, L = length) ratio is 10, the on/off ration and the mobility would be better, respectively. Moreover, the results also showed improvement in the performance of a-IGZO TFTs with the Al passivation layers and annealing process treatment.