| Summary: | 碩士 === 國立交通大學 === 光電工程學系 === 100 === Recently, 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). In addition, the uniformity of a-IGZO TFT is also superior to low temperature polycrystalline silicon TFT (LTPS TFT). Therefore, the a-IGZO TFTs have been widely considered to be the most promising candidate for the next generation display technology. a-IGZO TFTs showed good electrical performance, however, containing the rare-dispersive elements(In, Ga), will be an important issue for the long-term application. In this work, we developed rare elements-free oxide semiconductors--- amorphous Al-Zn-Sn-O thin film transistor (a-AZTO TFT).
We investigated on the physical characteristics and electrical performance of a-AZTO TFT under temperature effect of annealing process and plasma post treatment. The higher annealing temperature could strengthen the oxygen bonding, therefore the quality of the a-AZTO film improves. The electrical performance enhanced under high temperature of annealing process, as well. Moreover, O2 and N2O plasma could oxidize the AZTO film and eliminate some of the oxygen deficient. As a result, the reliability of the devices under GBS improved significantly after O2 and N2O plasma post treatment. The optical energy gap of a-AZTO films untreated and with O2 or N2O plasma treatment were about 3.5 eV which indicated that all of the a-AZTO films were insensitive to visible light. On the other hand, the electron mobility of a-AZTO TFTs enhanced after NH3 plasma post treatment. The improved device parameters could be attributed to H+ ions doping. These results showed the application potentials of a-AZTO TFT device on flat panel display technology.
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