Fabrication And Characterization Of IZO:Li/ZTO:Li Double-layer Thin Film Transistors

As oxide Thin Film Transistor(TFT)is widely used in flat panel display(FPD)field,more and more materials have proven to be a good active layer material,such as IGZO,ZTO,IZO,etc.With the development and progress of modern display technology,people also put forward higher requirements on TFT device performance,the traditional single TFT due to low mobility,more defect and higher annealing temperature limit,has been difficult to meet the requirements of industrial application.Only by changing the active layer material,has been difficult to fundamentally solve the problem of TFT device performance.To solve above problems,this paper,by using RF magnetron sputtering technique to prepare the IZO:Li/ZTO:Li double TFT active layer,and by optimizing the preparation conditions,successfully improve the performance of the double active layer devices.In this paper,the main research work is as follows:?.The influence of different annealing temperature on IZO:Li/ZTO:Li double active layer TFTs has been investigated.Different annealing temperatures have a great influence on the properties of the film such as resistivity,and therefore will greatly affect the device performance.When the annealing temperature is 400 ?,the double active layer devices achieved the mobility of 26.2 cm2/Vs,the threshold voltage of 4.3 V,Ion/Ioff of 1.3×1 07.?.We investigated the performance of the IZO:Li/ZTO:Li double active layer TFTs with different thickness of active layer in the same annealing temperature.For comparison,the performance of IZO:Li and ZTO:Li TFT devices was also studied at the same annealing temperature.When the thickness of IZO:Li film was 13 nm and the thickness of ZTO:Li film is 38 nm,the double active layer devices achieved the mobility of 33.2 cm2/Vs,the threshold voltage of 2.4 V,Ion/Ioff of 2.4×108.III.We investigated the performance of the IZO:Li/ZTO:Li double active layer TFTs with different Ar/O2 in the RF magnetron sputtering process.Different Ar/O2 will result in the change of weak bonding oxygen and other defects in the active layer film,thereby significantly affecting the device performance.Studies have shown that when the Ar/O2 is 30:0,the devices achieved the mobility of 39.4 cm2/Vs,the threshold voltage of-0.2 V,Ion/Ioff of 5.6×107.