Solution-Processed Ca-Doped Indium Oxide Thin-Film Transistors

Currently,oxide semiconductors have the advantages of high mobility,low production cost,and large-area production,which has gradually shaken the status of traditional silicon-based semiconductor materials.As a result,improving the performance of oxide semiconductors thin film transistors(TFTs)is a current research hotspot.Unlike magnetron sputtering,thermal evaporation and other thin film preparation methods,solution-processed method does not need to be carried out in a high vacuum environment,it is simple to operate,low cost,and able to be prepared in large area.It is one of the most widely used film preparation methods.In this paper,I adopted the solution-processed-processed method,and bottom-gate top-contact TFTs structure with calcium ions(Ca²⁺)doped indium oxides(In₂O₃)as channel layers.The performance of ethanol sensors with solution-processed In₂O₃ TFTs were studied,and it was concluded that calcium doping can improve the performance of ethanol sensor.This paper conducts research on the following four aspects:(1)In₂O₃ TFTs with Si/SiO₂/In₂O₃/Al structure were prepared by solution-processed method.The results show that the regulation of film thickness,annealing temperature,and annealing time can have great impacts on the performance of In₂O₃ films as well as TFTs devices.(2)By adjusting different Ca doping ratios,based on the Si/SiO₂/In₂O₃:Ca/Al TFTs structure,the impact of Ca doping concentration on the performance of In₂O₃ TFTs were studied,and the reasons were discussed.The results show that the TFT device has the best transfer curve characteristics when the doping concentration is 1%,and in the application of the inverter,the voltage gain can reach up to 74.9 when the applied voltage is 40 V.(3)Research on the performance improvement of In₂O₃:Ca TFTs based on high-k material aluminum oxide(Al₂O₃)as the dielectric layer.TFTs with 1%Ca doped In₂O₃ as the active layer and Al₂O₃ as the dielectric layer,can reach the mobility 6.8 cm² V^-1 s^-1,the threshold voltage-0.01 V,the subthreshold swing 0.096 V dec^-1 and switch ratio 3.1×10⁵,it has better performance than TFTs with SiO₂ as the dielectric layer.(4)Study on In₂O₃:Ca TFTs ethanol sensor application at room temperature.TFTs devices with interdigital structure were prepared,and the response of the devices to ethanol gas and mechanism analysis were studied.It is found that when 1%Ca doping,the sensing performance of TFTs is greatly improved,showing that Ca doping has the promising prospects for improving the sensing performance,therefore has the important research value.