The Study Of High-performance MgZnO Based Thin Film Transistors

The indispensable component in high-performance flat panel display industry is thin film transistor(TFT).The demand for high resolution,large-area and 3D display is driving scholars as well as industrial researchers to explore next-generation display material,because the traditional silicon-based transistors are far from being able to meet this demand.Recently,ZnO-based TFTs have been explored as potential alternatives for the new display industry due to their superior properties,such as high mobility,high optical transparency to visible light and high aperture rate.Despite the wonderful promise however,ZnO films propose a high carrier concentration by the presence of native defects,leading to a deteriorated electrical performance of thin film transistors.Many pioneering works have been devoted to solving the problem by the use of alloying heavy metal ions into ZnO film,MgZnO is one of scenarios to design the desired film properties.However,the corresponding parameters of MgZnO TFTs reported on the scientific theses of the academic periodicals were not enough to sustain the application of TFT-LCD.Based on above mentioned,the target of this study is researching the high-performance MgZnO based TFT and paying attention to various dopants with existed equipments.The main contents are as follows:(1)The MgZnO:N TFTs were fabricated by radio frequency magnetron sputtering and the mechanism on the electrical characteristics transition induced by the active thickness(ds)was also proposed.The corresponding electronic device exhibited the best performance at 35 nm;specifically,a saturation mobility of 3.4 cm2/V s,an on/off current ratio of 1.2×106 and a threshold voltage of 36.1 V.(2)The effect of annealing temperature on the properties of MgZnO:N TFTs were also investigated.The corresponding electronic device exhitbited a best performance at 300?;specifically,a saturation mobility of 4.6 cm2/V s,an on/off current ratio of 2.2x 106 and a threshold voltage of 32.5 V.(3)The MgZnO:Li TFTs were fabricated by radio frequency magnetron sputtering and the effect of sputtering Ar/O2 ratio on the properties of MgZnO:Li TFTs was investigated.The corresponding electronic device exhitbited a superior performance as the sputtering ratio was fixed at 30/3;specifically,a high saturation mobility of 12.9 cm2/V s,a large on/off current ratio of 2.5×107 and a threshold voltage of-15.1 V.(4)The bilayer InZnO:Li/MgZnO:Li TFTs were fabricated by radio frequency magnetron sputtering and the mechanism on the electrical characteristics transition induced by the active thickness of InZnO:Li film and MgZnO:Li film was also investigated.The corresponding electronic device exhitbited a superior performance;specifically,a high saturation mobility of 25.2 cm2/V s,a large on/off current ratio of 1.5x107 and a small threshold voltage of 5.7 V while the thickness of InZnO:Li film and MgZnO:Li film were fixed at 7 nm and 14 nm,respectively.