Preparation And Properties Of Amorphous InZnO-based Thin Film Transistors

Thin film transistor(Thin film transistor,TFT)is mainly used in the drive circuit of screen display.The performance and parameters of TFT will affect the size,resolution and image refresh rate of the display screen.Nowadays,the rise of virtual reality displays,augmented reality displays,and large-screen displays has required the modern display to further improve performance in terms of resolution and frame rate.To improve the performance of flat panel displays,it is necessary to improve the performance of TFT saturation mobility,ratio of on-state current to off-state current and subthreshold swing.The saturation mobility of amorphous silicon TFTs widely used nowadays is very small(not more than 1cm2 / Vs).And for high-performance low-temperature polysilicon TFTs,the uniformity of mass production is poor and the cost is high.In recent years,oxide materials as a new generation of semiconductors have received extensive attention and have been introduced into the research of thin film transistors.Among them,InZnO TFTs have been widely reported due to their high mobility.However,due to the doping of In,although the TFT has a relatively excellent saturation mobility,it also brings some disadvantages,such as: the off-state current cannot be effectively controlled,and the subthreshold swing deteriorates.In order to obtain high-performance TFTs that meet the needs of modern displays,based on InZnO materials,we hope to gradually adjust the performance of TFTs by means of element doping.This paper mainly carried out the following research and work:(1)InZnO material was doped with a small proportion of Li element,and In Zn Li O TFTs were prepared by magnetron sputtering deposition method at room temperature.In Zn Li O TFTs with different active layer thicknesses and In Zn Li O TFTs with different annealing temperatures were prepared separately,and related electrical properties were obtained by testing.Experimental data shows that by doping Li element,the mobility of the device is improved,but the off-state current is very large.(2)On the basis of experiment(1),we added Al element to In Zn Li O material,and prepared In Zn Al Li O TFTs by magnetron sputtering deposition method at room temperature.The effects of the active layer film thickness and annealing temperature on the performance of In Zn Al Li O TFTs were studied respectively,and the bias stability of In Zn Al Li O TFTs in air was studied.The experimental results show that the off-state current of the device prepared by doping Al is very small,but the mobility drops significantly.(3)Based on experiments(1)and(2),we replaced Li element with Ti element,and prepared In Zn Ti Al O TFTs by magnetron sputtering deposition method at room temperature.The effects of different annealing temperatures,different annealing gas atmospheres,and different active layer film thicknesses on the electrical properties of In Zn Ti Al O TFTs were investigated successively,and the bias stability of In Zn Ti Al O TFTs was tested in an air atmosphere.The experimental results show that,due to the incorporation of Ti and Al,TFTs with low subthreshold swing and off-state current are fabricated...