Fabrication And Properties Of ZnSnO Based Thin Film Transistor

Thin film transistors(TFTs)are the core components of TFT-LCD and AM-OLED,and the resolution and size of the flat panel display are determined by its characteristics.Traditional silicon based thin film transistors have been difficult to meet the above requirements due to low mobility,poor large area uniformity and so on,and the oxide TFTs may be applied to the next generation display devices,because its have many advantages,for example high mobility,large area uniformity and so on.However,the current metal oxide TFT still can not meet the needs of large capacity,ultra high definition,large size,ultra high resolution and 3D and other modern display technology development.Therefore,the metal oxide TFTs with high mobility are researched in this paper.1.Bottom gate type InZnO:Li TFTs were prepared by magnetron sputtering.The crystallization and light transmission properties of the active layer were investigated;the influences of the active layer thickness,annealing temperature,oxygen flow on the electrical properties were researched and the mechanism of the change law was also discussed.The InZnO:Li TFTs shows the best performance with mobility is 16.7 cm2/Vs,threshold voltage is 4.6 V,on-off ratio is 1.2×106.Additionally,the decay of electrical properties of InZnO:Li TFTs in air with time was investigated,and the results show that the device has good stability.2.Bottom gate type Zn0.5Sn0.5O:Li TFTs were prepared by magnetron sputtering.Study on the structure and optical properties of the active layer;the influences of active layer thickness,annealing temperature,oxygen flow and argon flow on the electrical properties of Zn0.5Sn0.5O:Li TFTs were researched,and the mechanism of its changes was discussed.The Zn0.5Sn0.5O:Li TFTs shows the best performance with mobility is 30.3 cm2/Vs,threshold voltage is 2.1 V,on-off ratio is 7.4×107.3.Bottom gate type Zn0.7Sn0.3O:Li TFTs were prepared by magnetron sputtering.Study on the structure and optical properties of the active layer;the influences of active layer thickness,annealing temperature and oxygen flow on the electrical properties of Zn0.7Sn0.3O:Li TFTs were researched,and the mechanism of its changes was discussed.The Zn0.7Sn0.3O:Li TFTs shows the best performance with mobility is 36.7 cm2/Vs,threshold voltage is 6.0 V,on-off ratio is 4.6×107.Then,the effects of Zn0.7Sn0.3O:Li TFTs vacuum annealing and device whole annealing on the electrical properties were investigated,the results show that both the vacuum annealing and the device whole annealing are unfavorable to improve the mobility of Zn0.7Sn0.3O:Li TFTs.4.Bottom gate type Zn0.9Sn0.1O:Li TFTs were prepared by magnetron sputtering.The crystallization and light transmission properties of the active layer were investigated;the influences of the active layer thickness,annealing temperature,oxygen flow on the electrical properties were researched and the mechanism of the change law was also discussed.The mobility of the Zn0.9Sn0.1O:Li TFTs can reach 45.1 cm2/Vs.Then,the decay of electrical properties of Zn0.9Sn0.1O:Li TFTs in air with time was investigated,and it has better stability.Finally,the influence of different Znand Sn ratio of ZnSnO:Li TFTs on their electrical properties is also discussed.