Solution Processed Zirconium-based Gate Dielectric Thin Films And Investgation Of Its Devices' Properties

According to the effect of Moore's law,the integration of integrated circuits is getting higher,and the size of MOSFET,the smallest unit of integrated circuits,is shrinking.As a result,the traditional gate dielectric SiO₂ layer has to be reduced to the atomic size,which result in a dramatically increase of leakage current and the device will not work as usual.So it appears to be extremely imminent to find high-k new materials to replace SiO₂ gate dielectric.With the continuous exploration and research,it is found that the Zr-based high dielectric gate material has a high dielectric constant and crystallization temperature,excellent interface characteristics and internal structure and small leakage..current.All these advantages make it possible for the Zr-based high dielectric gate material to replace the traditional SiO₂ gate dielectric material in future MOSFET devices.Thin film transistor?TFT?is a key component in the display industry,its performance directly influences the display quality of the display.In order to improve the performance of transistors,the application of high-k materials in thin-film transistors,which can reduce transistor power dissipation,sub-threshold swing and improve carrier mobility,has attracted wide attention.So high-k materials have good application prospects in MOSFET and TFT devices.In this paper,the Zr-based high-k gate dielectric thin films materials was doped by boron?B?,titanium?Ti?,gadolinium?Gd?with solution method.Their properties,such as structure,optics,electricity and interface,were systematically studied.At the same time,the TFT devices were prepared by solution method.Based on the SiO₂ gate dielectric,the effects of different channel layers and annealing temperature on the properties of the devices were investigated.According to the solution method,high-k materials and the TFT devices were prepared.Besides,this paper also studies the effects on the properties of the devices brought by the differences of gate dielectric layer and active layerThe main research contents and results of the paper are as follows:1.ZrO₂ thin films were prepared by sol-gel method.The effects of annealing temperature on structure,optical and electrical properties of the films were studied.The mechanism of the leakage was also analyzed.It can be concluded that suitable temperature annealing can improve quality and reduce defects of the dielectrics.2.B doped ZrO₂ thin films were prepared by sol-gel method,and their structures,optical and electrical properties were studied.The main leakage cruuent mechanism was analyzed and the optimal B incorporation was obtained,3.ZrTiOx thin films were prepared by sol-gel method.The effect of annealing temperature on the structure,optical and electrical properties of ZrTiOx thin films were studied.The properties of ZrTiOx dielectrics were compared with the ZrO₂ film in this chapter.It can be concluded that Ti can improve the quality of interface,reduce the hysteresis,improve the dielectric constant of the film.4.Different Gd content incorporated ZrO₂ films wre prepared by sol-gel method and the Gd:ZrO₂/Si interface properties were characterized by XPS,and the electrical properties of the dielectrics were systematically studied.The results show that Gd can suppress the growth of SiO₂ and improve the performance of MOS device.The optimum doping concentration can also be obtained.5.The TFTs were prepared by solution method.The dielectric layer was composed of SiO₂ thin films grown by thermal oxidation and solution-grown high-k gate dielectric films,including ZrOx and ZAIOX.The active layer is prepared by the sol-gel method,and the channel layer materials involve In₂O₃,IZO and HIZO semiconductor thin films.The source and drain were A1 electrodes grown by thermal evaporation.The output and transfer curves were measured and the performance parameters such as threshold voltage,carrier mobility,subthreshold swing and switching ratio were calculated and analyzed from the transfer curves.