Interface Modification of ZnO -based thin film transistor characteristics
|School||Beijing Jiaotong University|
|Keywords||Zinc oxide Interface Modification Lithium fluoride Field-effect mobility Pentacene|
The main contents of this paper to study the zinc oxide film as an active layer, preparing zinc oxide thin film transistor (ZnO-TFT), respectively, from the zinc oxide film thickness, the use of different materials interface modification, as well as organic and inorganic compound such as the angle of oxidation the electrical properties of the thin film transistor of zinc were studied. First, the magnetron sputtering method, a purity of 99.99% zinc as a target, by controlling the different ratio of argon and oxygen, and adjusting the sputtering power, zinc oxide thin film of preparation for the optimal deposition conditions. By study found that in Ar: O2 was 30sccm: 25sccm, sputtering power of 300W, 400 ℃ annealing 10min when tested by XRD and AFM film in this condition indicates the best quality. Secondly, in the optimal deposition conditions, using magnetron sputtering method, by controlling the sputtering time, respectively, in 600s, 800s, 1000s, 1200s sputtering time, to obtain a 45nm, 60nm, 75nm, 95nm four different thickness layer of zinc oxide thin film was prepared out of the device, the electrical properties of the test are obtained at time 600s sputtering zinc oxide thin film transistor of a better quality, mobility was: 0.789cm2 / V · s , as the sputtering time is increased from 800s to 1200s of the mobility of the device are: 0.271cm2 / V · s, 0.271cm2 / V · s, 0.285cm2 / V · s, characterized by XRD and AFM found 45nm thickness, the film perpendicular to the substrate while the substrate and parallel to the growth direction, along the direction of carrier transport goods boundary density is low, the top surface morphology, the best film quality, so the relative performance of the resulting transistor best. Third, the use of lithium fluoride layer and an aluminum electrode of the active interface between the modified lithium fluoride found that by modifying the interface device have increased the mobility of the active layer thickness is 45nm, the device The migration rate of 0.920cm2 / V · s, 800s to 1200s of the device from the migration rate was 0.278 cm2 / V · s, 0.319cm2 / V · s, 0.304 cm2 / V · s. Subsequently, the molybdenum oxide and the aluminum of the device active layer interface between the electrode of the modification, found that by modifying the interface of molybdenum, the device have decreased mobility in the active layer thickness is 45nm, the device migration rate fell to 0.531cm2 / V · s, a thickness of 95nm mobility of the device of 0.263 cm2 / V · s. Fourthly, the effect of different thickness and quality of pentacene thin film by thermal evaporation, prepared eight 5,10,15,20,30,40,50,60 nm and a thickness of pentacene thin film obtained by XRD analysis of the Preparation of film thickness of 10nm to 40nm better film quality. Fifth, zinc oxide and two different pentacene active layer made of composite zinc oxide / pentacene thin film transistors (ZnO / Pentacene-TFT), the use of zinc oxide film by thermal evaporation and pentacene thin film layer prepare a ZnO / Pentacene-TFT, found through experiments without the addition of the interface in the case PhTMs modified material, high mobility of the device there is PhTMs modification of the device, mobility of 0.552cm2/Vs. Finally, prepared pentacene thickness 10nm, 20nm, 30nm, 40nm, 45nm thickness of zinc oxide of the four devices, and found by measuring the electrical properties of ZnO film thickness 45nm, and a film thickness of pentacene when 1Onm The device mobility highest 0.552cm2/Vs.