A study on the high mobility and improved reliability of Pr-doped indium zinc oxide thin film transistors

It is generally accepted that there is a trade-off relationship between mobility and stability for oxide thin film transistor (TFT) devices. Different doping ratios of Ln praseodymium (Pr) into indium (In) zinc (Zn) oxide have been employed as the active layer to get 1# and 2# amorphous oxide semiconductor (AOS) TFTs in this work. The 1#-based TFTs exhibited a high mobility of 49.84 cm2 V−1 s−1 due to the increased concentration of In. By further elevating the Pr doping ratio of the film, the 2#-based TFT obtained both a good mobility of 26.65 cm2 V−1 s−1, and a promising stability, showing a positive-bias temperature stress (PBTS) stability of ∆VTH = 1.56 V and a negative-bias temperature illumination stress (NBTIS) stability of ∆VTH = −1.47 V. It was revealed that the low energy charge transfer state of Pr in 2# film absorbs the visible light, leading to suppressed photo-induced carriers and thus a good illumination reliability of the 2#-based TFTs. In practice, the LCD panel based 2# ACT TFT shows a well stable performance even under 10000-nit illumination. The result indicates a promising strategy to accelerate the commercialization of AOS TFTs to large-panel display production.