Fabrication Of High Performance In₂O₃ Thin Film Transistors By Full Aqueous Solution Method And Its Application In Logic Devices

Metal oxide semiconductors,as excellent channel materials for thin film transistors(TFTs),have important applications in liquid crystal display(LCD),active matrix organic light emitting diodes(AMOLED)and other emerging electronic applications(such as complementary metal oxide semiconductors(CMOS)and logic devices).Compared with traditional silicon-based thin film transistors,metal oxide thin film transistors(MOTFTs)have been extensively studied due to their high mobility,low temperature synthesis process,good stability and high optical transmittance.Based on the cost-saving and environment-friendly development strategy,current work adopts a non-toxic,environment-friendly and low-cost aqueous solution method(solution method with water as solvent)as the key technology to fabricate devices,and introduces the high-k dielectric material to replace the traditional SiO2 insulating layer in order to pursue lower power consumption of TFT devices.Finally,TFT devices with optimized performance are applied to resistor-loaded inverters.The specific research contents and results are divided into the following three parts:1.In2O3 thin films were prepared by aqueous solution method.The structure,optical,surface roughness and chemical composition of In2O3 thin films prepared by aqueous solution method were systematically studied.The possibility of using In2O3 thin films as TFT channel layer was also discussed.Based on the preparation of ultra-thin(20 nm)Al2O3 insulating layer at low temperature of ALD 200 ?,an In2O3/Al2O3 TFT device was fabricated.The effect of annealing temperature on the electrical properties of TFTs was studied.The devices annealed at 280 ? exhibit optimized electrical properties with a mobility of 11.85 cm2V-1S-1,resistor-loaded inverter based on In2O3/Al2O3 TFT also exhibit good inverter performance.Results have shown the potential application prospects of In2O3 thin film transistors in low-cost,low-power,large-area environmentally friendly oxide flexible electronic devices.2.A novel ZrAlOx dielectric thin film was prepared by a simple,low-cost and environmentally friendly aqueous solution method.The effects of the annealing temperatures on the microstructure,transmittance,surface morphology,chemical composition and electrical properties of ZrAlOx thin films were studied.Results show that the ZrAlOx films annealed at 500 ? have good amorphous state,high transmittance,smooth surface morphology,large area capacitance and low leakage current density.In2O3/ZrAlOx TFTs have been successfully fabricated by full aqueous solution method.TFT devices show excellent low voltage(3 V)drive capability.Resistor-loaded inverters exhibit good voltage transfer characteristics and high voltage gain.In addition,dynamic response characteristics with full pendulum characteristics are obtained at low voltage of 2 V.These excellent parameters demonstrate their great application value in low cost,high transparency,portable and low power electronic devices.3.ZrGdOx dielectric thin films were prepared by aqueous solution method for the first time,and their applications in TFT devices were studied.Results show that ZrGdOx films annealed at 400 ? have excellent dielectric properties.In2O3/ZrGdOx TFT was successfully fabricated by using the full aqueous solution method and a resistor-loaded inverter was constructed.The optimized TFT annealed at 250 ?showed excellent electrical properties with 1 8.82 cm2V-1S-1 mobility and Ion/Ioff of 107.Resistor-loaded inverters have full swing characteristics and gain with 7.4.This is an important step to realize low cost,low power consumption and large area oxide flexible electrons.