Preparation And Properties Of AZTO Thin Film Transistor Devices By RF Magnetron Sputtering

With the rapid development of science and technology,thin film transistors(TFT)have attracted people's attention.As the core component of high-end flat panel displays(FPD),thin film transistors are widely used in curved screens,wearable devices,and portable display devices.For a long time,indium gallium zinc oxide(IGZO)thin film transistors have been the focus of research by experts at home and abroad.Although its TFT has shown good electrical properties,for long-term development,the problem of In and Ga being rare elements has not been well resolved.Therefore,the new indium-free oxide semiconductor is considered to be the most promising semiconductor material in the future.Aluminum zinc tin oxide(AZTO)as a new indium-free material has caused extensive research by experts at home and abroad in recent years.Sn has the effect of increasing the carrier concentration due to its special outer electronic structure,and the high combination of Al³⁺and O^2-,Can control the carrier concentration in the channel layer.The most important thing is that Al and Sn materials are very abundant and common on the earth.Therefore,theoretically,AZTO can replace IGZO as the active layer channel of the device.In this paper,the co-sputtering technology is used to prepare TZO films on silicon substrates,and the morphology,structure and optical properties of the films are characterized by means of SEM,XRD,and UV-Vis.Mix high-purity Zn O,Al₂O₃,and Sn O₂powders into a target.Use radio frequency magnetron sputtering to prepare the AZTO film as the channel layer and Si O₂as the gate dielectric layer on a silicon substrate.(EB)Evaporate aluminum electrode to make thin film transistor.Study and analyze the effects of annealing temperature and active layer thickness on AZTO thin film and thin film transistors.The main contents are as follows:(1)TZO film and its thin film transistor:By changing the sputtering power of Sn,it is concluded that when the sputtering power of Sn is 20 W,the average transmittance of the TZO film in the 200-800 nm band is 90%,and the crystal quality of the film better.We further prepared TZO-TFT devices under different Sn sputtering powers,and found that as the sputtering power of Sn increases,the mobility of the device first increases and then decreases,indicating that Sn has the effect of enhancing carrier mobility.But it is not that the larger the sputtering power of Sn,the better.When the sputtering power of Sn is 20 W,the overall electrical performance of TZO-TFT is the best,with a mobility of 5.3 cm²/(Vs)and a threshold voltage of 10.4V.Switch ratio is 2.83×10⁸.(2)AZTO film and its thin film transistors:By changing the annealing temperature,it is concluded that when the annealing temperature is 600?,the average transmittance of the AZTO film in the 200-800 nm band is 95%,and the thinning quality of the film is greatly improved And the AZTO-TFT device has the best electrical performance,with a mobility of 10 cm²/(Vs),a threshold voltage of 13V,and a switching ratio of 6.29×10⁶.(3)AZTO film and its thin film transistor:By changing the thickness of the AZTO film and fixing the annealing temperature at 600?,it can be concluded that when the film thickness is 70 nm,the average transmittance of the film in the 300-800nm band is 92.6%.The film quality is the best,the field-effect mobility of the device is 3.6 cm²/(Vs),the threshold voltage is 8.51 V,and the switching ratio is 1.4×10⁶.