| Thin film transistors(TFTs)are one of the indispensable electronic components in the field of flat panel display.As the display technology moves toward large size,high resolution,3D display,etc.,traditional Si-based TFTs can't meet the development need of current display technology due to low mobility for amorphous silicon TFTs,and poor uniformity against large-area preparation for poly-crystalline silicon TFTs.Oxide thin film transistors have been highly anticipated due to their high mobility,good transparency in the visible range,and excellent uniformity against large-area preparation.Among oxide thin film transistors,In-containing InZnO-based thin film transistors typified by InZnO,InGaZnO,and HflnZnO have attracted a lot of researchers attention and have been extensively studied because,in contrast to other In-free oxide thin film transistors,the incorporation of In often makes them achieve a higher mobility;however,In and Ga belong to rare metals,and they are limited and expensive.Based on this,people are actively researching and exploring in order to obtain high mobility thin film transistors and to reduce the cost of raw materials to meet the development of display technology.As a result,this thesis has also carried out the following research work:(1)Sn was substituted for In,and the In-free ZnSnO TFT with bottom-gate staggered structure were successfully prepared by radio frequency magnetron sputtering.The effects of active layer thickness,annealing temperature,oxygen gas flow rate and argon gas flow rate on the properties of ZnSnO TFT was investigated in this work.The experimental results showed that when the values of the active layer thickness,the annealing temperature,oxygen gas flow rate and argon gas flow rate were 46nm,600?,3sccm and 30sccm,respectively,the ZnSnO TFT exhibited the best device performance,namely a high saturation mobility of 36.4 cm2v-1s-1,a large on/off current ratio of 9.7× 107 and a threshold voltage of 3.2V.(2)N-doped ZnSnO TFT was successfully prepared by radio frequency magnetron sputtering.The effect of active layer thickness,annealing temperature,oxygen gas flow rate and sputtering power on the properties of N-doped ZnSnO TFTs were studied,and the stability of the device placed in the air was explored.The experimental results show that when the value of the active layer thickness,the annealing temperature,the oxygen flow rate and the sputtering power were 59nm,635?,Osccm and 100W,respectively,the N-doped ZnSnO TFT exhibited the best device performance,namely a high mobility of 42.8 cm2v-1s-1,a large on/off current ratio is 1.9×109,and a threshold voltage of 2.8V.After the device was placed in the air for 90 days,the performance of the device was slightly degraded.Its mobility,on/off current ratio and threshold voltage were 36.1 cm2 v-1s-1,1.9×106 and-1.0V,respectively.(3)Li and N were simultaneously incorporated into the ZnSnO system.Li-N co-doped ZnSnO TFTs were successfully prepared by radio frequency magnetron sputtering.The influence of active layer thickness,annealing temperature and oxygen gas flow rate on the performance of the Li-N co-doped ZnSnO TFT was investigated.The stability of the device placed in air was explored.The experimental results showed that when the value of the thickness of the active layer,the annealing temperature and the oxygen flow rate were 54nm,675? and Osccm,respectively,the Li and N co-doped ZnSnO TFTs achieved the best device performance,namly a high mobility of 26.8 cm2v-1s-1,a large on/off current ratio of 4.5×107 and a threshold voltage of 6.0V.After the device was placed in the air for 90 days,the performance of the device was slightly degraded.The mobility of it was 24.5 cm2v-1s-1.The on/off current ratio of it was 9.3 ×105.And the threshold voltage of it was 3.0V. |
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