Transient Characteristics Investigation Of Metal Oxide Semiconductor And Its Application In Thin Film Transistor

Traditional semiconductor oxides are widely used in active matrix display transistors,transparent and flexible electronic devices.In recent years,some electronic equipments,whose key characteristic is the ability to dissolve in water,with biological or environmental degradation,or those that can physically disappear or transform on demand,have attracted people's attention.In this type of transient electronic devices,in addition to biopolymers and crystalline silicon,oxide has also become a common transient semiconductor material.Compared with the previous transient electrons based on silicon,oxide thin film transistors have the characteristics of high performance,large area preparation,and ultraviolet light response.It has become the focus in the field of transient transistors.semiconductor oxide thin films fabricated by solution method has many advantages,such as simple process and equipment.It can also be used to fabricate large area devices and avoid or reduce the use of vacuum equipment,thus meeting the requirements for the preparation of transient oxide thin film transistors to low temperature process.Under this background,this paper explored the fabrication method of transient oxide thin film transistors with bottom gate structure,in-depth study of the transient characteristics of the oxides represented by ZnO,and various methods to improve the performance of oxide TFT.The main contents are as follows:1)The relationship between the dissolution characteristics of ZnO materials and the dissolution environment was explored.The results show that zinc oxide materials can be dissolved in phosphate buffer saline solvents in both high acid(PH=3)and high alkaline solutions(PH=12),but in neutral environments,zinc oxide materials are difficult to be completely dissolved in phosphate buffer saline solvents.In addition,the higher the temperature,the faster the dissolution rate of ZnO materials;2)After determining the dissolution characteristics of ZnO,the fabrication of TFT with bottom gate structure was investigated.Zinc oxide TFT devices with mobility of 1.14 cm2/V·s were fabricated by solution spin-coating method.The threshold voltage of the device was up to 15V,the switching ratio was 5.16×107,and the sub-threshold swing was 590mV/dec;3)The performance of the ZnO-TFT prepared by the solution spin coating method is to be improved,and therefore,the preparation method of the TFT with higher performance is explored.Firstly,immerse cylindrical aluminum particles in the precursor solution for doping,and the carrier concentration in ZnO film is increased.The mobility of the device was increased to 2.76 cm2/V · s.Then,the TFTs,whose active layer of zinc oxide was doped by magnetron sputtering,have the mobility of 5.28 cm2/V·s when the doping time is 3s,which greatly simplifies the fabrication process while improving the device performance.Moreover,the IGZO films are prepared by sol-gel method as active layer for TFTs.The roughness of IGZO film was improved and the mobility of the device was 4.2 cm2/V· s and the electrical properties of the devices are improved.Lastly,the IZO films are prepared by spin-coating method as active layer for TFTs.The devices with high electrical properties were obtained at 300 ? annealing temperature with a mobility of 7.56 cm2/V·s.The above four methods have achieved the effect of improving the electrical properties of TFT;4)Mg was deposited by electron beam evaporation,and the ZnO-TFT transient device was prepared using metal Mg as electrode.The device was dissolved in DI water at 37 ?.The Mg electrode dissolved obviously in 4min,and the dissolution rate is about 20 nm/min.The dissolution rate of zinc oxide in deionized water is about lnm/h.The performance of the device gradually failed.