Research On The Influence Of Preparation Conditions Of A-IGZO Thin Film Transistor On Device Performance

Thin film transistor?TFT?is the core component of flat panel display.Any active matrix flat panel display depends on the control and drive of TFT.With the rapid development of flat panel display technology,traditional amorphous silicon thin film transistors are increasingly difficult to meet the needs of the display industry.Meanwhile,TFT with indium gallium zinc oxide?a-IGZO?as active layer is developing rapidly.Compared with amorphous silicon TFT,a-IGZO TFT has many advantages,such as high mobility,good transmittance and low film forming temperature.It has more advantages in high-definition display and flexible display.In order to test the electrical performance of a-IGZO TFT and explore the preparation process for optimizing device performance,the effects of preparation conditions of active layer?such as annealing temperature,Ar plasma treatment time,oxygen partial pressure,High-K gate dielectrics?on device performance are studied in this paper.?1?The effect of annealing temperature on device performance was studied.Experiments show that the switch ratio of the device is the best at 350?,reaching 10⁹.With the increase of temperature,the switch ratio decreases.The best mobility of the device is 19.8 cm²/V·s at 350?.At 350?,the open voltage is maintained at about 0V.The sub-threshold swing is the smallest at 350?,which is 0.65.The lowest threshold voltage is 11V at 400?.In conclusion,the device has the best performance when the annealing temperature is 350?.?2?The effect of plasma treatment time on the performance of a-IGZO active layer is studied.Experiments show that with the increase of processing time,the maximum current Idmax increases first and then decreases,with the maximum current Idmax at200s.When the time of argon plasma treatment is 200 s,the contact resistance is the smallest.?3?The effects of three oxygen partial pressures on device performance were studied.From the Id-Vg curves of the transfer characteristics of a-IGZO TFT samples with different oxygen partial pressures,it can be seen that when the oxygen partial pressure is4.5%,the device has the best comprehensive performance.?4?The influence of High-K gate dielectrics on device performance is studied.For TFT with 90 nm SiO₂ as gate medium,at present the maximum field effect mobility can reach 21cm²/V·s and the switching ratio can reach 10⁹.For TFT with 20nm HfSiOx as gate medium,the maximum field effect mobility can reach 13 cm²/V·s at present.Vth,SS and Rc have been greatly improved compared with low dielectric constant materials SiO2,which are 1.2 V,0.14 V/dec,4.67?·mm.