This paper focuses on the comparison and analysis of ZnO TFT's and IGZO TFT's optical and electrical performance, and the stability of threshold voltage.The comparison results indicate that both ZnO and IGZO thin film materials have a simply high optical transmittance in the range of visible spectrum.Furthermore, the key electrical properties of IGZO TFT are better than that of ZnO TFT under the same deposition condition, such as the field effect mobility, the on/off ratio, the threshold voltage and the subthreshold slope.The leakage current of both ZnO TFT and IGZO TFT is low, and the difference between them is rather small.In addition, the threshold voltage of ZnO TFT is shifted under the positive or negative gate bias stress.However, the threshold voltage shift of IGZO TFT is smaller than that of ZnO TFT, and there is no threshold voltage shift for IGZO TFT under the negative gate bias stress.Therefore, IGZO TFT is more stable than ZnO TFT.In conclusion, IGZO thin film material is more suitable to be the active layer of the next generation of TFTs.%分析比较了ZnO TFT与IGZO TFT的主要光电学特性以及阈值电压稳定性.结果表明:ZnO薄膜与IGZO薄膜在可见光波长范围内都有着较高的光学透过率;在同等制备条件下,IGZO TFT器件的场效应迁移率、开关电流比、阈值电压及亚阈值系数等方面的特性均明显好于ZnO TFT;二者都有着较低的泄漏电流,并且差别很小.另外,ZnO TFT在正负偏压下阈值电压都有漂移,而IGZO TFT在正偏压下阈值电压漂移比ZnO TFT的小且在负偏压下阈值电压没有漂移,由此可见IGZO TFT比ZnO TFT有着更好的稳定性.总之,IGZO薄膜比ZnO薄膜更适合作为下一代TFT的有源层材料.
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