Solution-driven Metal Oxide Thin Film Transistors And Its Performance Optimization

In our current information society,the use of thin film transistor（TFT）devices has become an effective and powerful means to convey complex information.TFT can be used for display devices as small as mobile phones,tablet computers and notebook computers,as large as televisions,monitors,billboards and other large screens.TFT devices prepared by solution method have the characteristics of simple process,low cost,controllable component ratio and easy mass production.In this paper,high-k gate dielectric layer and channel layer are prepared by solution method,and metal oxide TFT is constructed.The structural characteristics,electrical properties,illumination and bias stability of TFTs devices are systematically studied.The research shows that the prepared TFT has the advantages of low driving voltage,high mobility and high stability.The main results of this paper are as follows:1.Based on a simple,non-toxic,environment-friendly and aqueous solution driving route,In₂O₃/HfO₂ TFTs were successfully fabricated on Si substrate,and the electrical properties of In₂O₃/HfO₂ TFTs were systematically studied.The results show that after annealing at 500℃,In₂O₃/HfO₂ TFT shows the best electrical properties,including carrier mobility of 9 cm²/V?s,I_ON/I_OFF of 10⁵,threshold voltage as low as 1.1V and subthreshold of 0.31 V dec^-1.The stability under positive bias（PBS）and negative bias（NBS）is tested at a small working voltage of 2V,and the threshold shift（VTH）is only 0.35 and 0.13 V.Comprehensive experiments show that the preparation of TFT by aqueous solution technology has potential application value and can be widely used in the future low-cost,energy-saving,large-scale and high-performance electronic fields.2.NiInO/SiO₂ TFTs were fabricated based on solution method and doping process,and the effects of nickel doping on its microstructure and TFT transmission characteristics were systematically studied.The results show that with the increase of nickel doping,the concentration of oxygen vacancies in NiInO decreases,which leads to the decrease of on/off current and the positive shift of threshold voltage.Among them,NiInO/SiO₂ TFT doped with 0.5%nickel shows better electrical properties,including mobility of 7.54 cm²/V?s,switching current ratio of 10⁷,threshold voltage of 6.26 V and low interface trap state(D_it)of 8.23×10¹²cm^-2,and shows improved bias stress stability.The reason why doping leads to the improvement of performance may be due to the small ionic radius,high Lewis acid value and strong NiO bond strength of nickel.In addition,NBS（NIBS）measurements show that short-wave irradiation will reduce the device stability,which may be due to the ionization of oxygen vacancies induced by short-wave irradiation.The experimental results confirm the potential of solution treatment technology in large-scale,low-cost and high-performance electronic products in the future.