| Summary: | 碩士 === 國立交通大學 === 電子工程學系 電子研究所 === 103 === Amorphous oxide semiconductors (AOSs) are attracted much attention due to high mobility, low temperature deposition, flexible, transmission, and uniformity. It has been investigated of AOSs, such as ITO, IZO, TiO2, ZnO, In2O3, Ga2O3, IGO, a-IGZO, etc. Especially, the thin film transistors (TFTs) with a-IGZO thin film as active layer perform higher mobility and better reliability than conventional hydrogenated amorphous silicon TFT (a-Si:H TFT). Therefore, the a-IGZO TFTs have the potential to replace a-Si: H TFT and LTPS TFT forming Active Matrix Organic Light Emitting Display (AMOLED). However, a-IGZO there are some inherent defect, such as sensitive to water and oxygen in ambient environment thereby affect the device stability. The device reliability under GBS also has to be considered. In this work, we presents the electrical characteristics of the nitrogenated amorphous InGaZnO thin film transistor (a-IGZO:N TFT) for the first part. The a-IGZO:N film acting as a channel layer of a thin film transistor (TFT) device was prepared by DC reactive sputter with a nitrogen and argon gas mixture at room temperature. Experimental results show that TFT electric parameters and reliability degrade with increasing nitrogen flow rate due to in situ N doping method during a-IGZO:N film preparation may form an unstable interface between dielectric and channel layer and average interfacial trap density (Nt) increases with increasing nitrogen flow rate confirmed by Low-Frequency measurement analysis. For the second part, N2O plasma treatment is executed on the SiO2 dielectric surface to improve the instability behavior of the a-IGZO:N TFTs. The superior device characteristics of IGZO:N-based TFTs can be achieved. Moreover, the role of nitrogen doping has been investigated. With a proper amount of in situ nitrogen doping, nitrogen doped TFT can reduce the oxygen vacancy and total trap densities then demonstrate superior electric characteristics, improved reliability, and smaller falling-rate (FR). These results showed the application potentials of a-IGZO:N TFT device on flat panel display technology.
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