The Study Of The Preparation And Property Of Oxide Gate Dielectric Thin Film Transistor

The biggest advantage of solution-processing compared to typical preparation methods for thin film transistors(TFTs) that the technology is simple, it has received more and more attention for its unique advantages of low cost, simple equipment and process, uniform film-forming and large-scale preparation, etc. In this paper, TFT based on solution-processed alumina(Al2O3) was chosen as the research topic, the major target is to gain low-voltage high performance device. We primarily studied the effect of Al2O3 insulating layer annealing temperature on the performance of TFT and the improvement by polymer modified the insulation and also the property of low-temperature fabrication of insulation via combustion device. Specific contents are divided into three parts:1. The research of TFT device performance based on Al2O3 insulation. By using high dielectric constant Al2O3 as an insulation, we investigated the influence of insulation with different annealing temperature on the performance of pentacene TFT. With the annealing temperature increasing from 150 ℃ to 350℃, the device performance does not have an obvious change. When the annealing temperature of insulation is 350 ℃, the mobility up to 0.375 cm2/(V·s) and the switch current becomes 5.17×103. A major reason for the improvement of device’s performance is the insulation low surface roughness at a high annealing temperature, the crystal inity improvement of pentacene growing in this device, and the low interface trap density between semiconductor layer and insulating layer.2. The influence of polymer modified insulating layer on the device performance research. Based on the preparation of low voltage and high performance devices, using low polymer interface characteristics of polarity, the effect of polymer modified insulating layer on the device is studied. Compared with single Al2O3 as the device insulation layer, the results show that the insulation layer is modified by PMMA, device performance is improved. Device mobility increased to 0.496 cm2/(V·s), current switch ratio increased to 5.43×104. The device performance is attributed to the low dielectric constant polymer modified insulation layer to optimize the surface roughness and reduce the interfacial polarity. Reduce the binding of carriers in the transmission process, while reducing the interface trap density.3. Study on TFT performance of insulation layer prepared by combustion method. By adding fuel in the solution, the heat release reaction of the fuel is used in the heating process, so as to achieve the purpose of reducing the annealing temperature of the insulating layer. After adding acetylacetone and ammonia water in solution, the annealing temperature of the insulation layer is reduced to 180 ℃. I-V, C-V and AFM are used to test the film that combustion method can prepare films with good performance. On the basis of it, the TFT device migration rate is 0.291 cm2/(V·s), the current switch ratio is 8.69×102. Based on polymer modification can improve the performance of the device, using PMMA to modify the insulation layer, the device mobility is increased to 0.385 cm2/(V·s), the current switch ratio is 2.74×103. Low voltage drive thin film transistors were prepared by the solution method at low temperature.