【作者】 李彬；

【导师】 衣立新； 张希清；

【作者基本信息】 北京交通大学 ， 光学工程， 2016， 博士

【摘要】 薄膜晶体管(thin film transistor,TFT)是平板显示技术的核心部件。随着科技的发展,平板显示技术正朝着高容量、高分辨率、高驱动、3D和大尺寸的方向发展。目前,工业中常用的非晶硅薄膜晶体管,其迁移率不足Icm2/Vs;多晶硅薄膜晶体管的均匀性又差,并且硅基薄膜在可见光范围内透光性差,这些都制约着薄膜晶体管的发展。氧化物薄膜晶体管由于具有较高的迁移率、开口率大等优点,已经引起研究人员的广泛关注。为了满足现代显示技术与3D显示的需求,如何进一步地提高薄膜晶体管的迁移率,是目前需要解决的热点问题。针对这一问题,本文主要制备了In2O3:Li TF、In0.8Zn0.2O:Li TFT和In0.67Zn0.33O:Li TFT,并通过优化实验条件,得到了高性能的氧化铟基TFT器件。主要研究工作如下：(1)用磁控溅射制备了底栅极结构的In203：Li TFT。研究了退火温度、有源层厚度和氧气流量对TFT器件性能的影响。实验结果表明,当有源层厚度为30nm,退火温度为200℃,氧气流量为2sccm时,TFT器件的性能最佳,其迁移率为14.6cm2/Vs,开关比为9.0×106,阈值电压为5.2V。(2)用磁控溅射在SiO2/Si衬底上制备了In0.8Zn0.2O:Li TFT.研究了有源层厚度、氩气流量、退火温度和退火气氛对TFT器件性能的影响,并成功制备出双有源层结构的TFT器件。实验结果表明,当有源层厚度为30nm,氩气流量为30sccm,退火温度为950℃,在氧气气氛退火时,TFT器件的性能最佳,其迁移率达到56.1cm2/Vs,开关比为5.1×106,阈值电压为2.0V；与单层结构相比,双有源层结构的TFT器件性能有所提升,其迁移率为62.1cm2/Vs.(3)用磁控溅射在石英衬底上沉积了In0.67Zri0.33O:Li薄膜,研究了退火温度对In0.67Zn0.33O:Li薄膜的影响。以SiO2/Si为衬底制备了In0.67Zn0.33O:Li TFT,研究了氧气流量、溅射功率、有源层厚度和退火温度对TFT器件性能的影响,并且探讨了TFT器件的稳定性。实验结果表明,当薄膜生长不充氧,溅射功率为100W,有源层厚度为30nnm,退火温度为950℃时,TFT器件的性能最佳,其迁移率高达80.4cm2/V s,开关比为4.0×106,阈值电压为4.1V。该TFT器件的性能在文献报道中属于最佳性能之一。对于未采取任何保护措施的TFT器件,在空气中暴露90天后,其迁移率略下降到73.1cm2N/Vs,表明该TFT器件具有良好的稳定性。更多还原

【Abstract】 Thin film transistors (thin film transistor, TFTs) are the key components in flat panel displays. With the development of the science, the trend of flat panel displays is high capacity, high resolution, high drive,3D and large size. In the industry, the mobility of amorphous silicon TFTs is less than 1cm2/V s, and the uniformity of polycrystalline silicon TFTs is poor. Moreover, these Si-based TFTs are opaque in the visible wavelength region, which restricted the development of thin film transistor. Due to high mobility and transparency, the oxide TFT has attracted much attention. In order to meet the requirement of the modern display technology and 3D display, there is a hot issue to be solved, which is the way to improve the mobility of thin film transistors. In this work, In2O3:Li TFT、In0.8Zn0.2O:Li TFT and In0.67Zn0.33O:Li TFT were fabricated. The high performance of indium oxide based TFT devices were obtained by optimizing the experimental parameters. Major works as follows:(1) In2O3:Li TFTs with bottom gate structure were produced by radio frequency magnetron sputtering. The effects of annealing temperature, the active layer thickness and the oxygen gas flow rate on the electrical properties of TFTs were investigated, respectively. The experimental results indicated that the TFTs with an 30nm In2O3:Li films, annealed at 200℃ and oxygen gas flow rate of 2sccm, have the best electrical properties:a field effect mobility of 14.6cm2/V s, an on/off current ratio of 9.0×106 and a threshold voltage of 5.2V.(2) The Ino 8Zno.20:Li TFTs were fabricated on SiO2/Si by magnetron sputtering. The effects of the active layer thickness, argon gas flow rate, annealing temperature, and annealing atmosphere on the electrical properties of TFTs were studied, respectively. Meanwhile, the TFT device with double active layer structure was fabricated. The experimental results indicated that the TFTs with an 30nm In2O3:Li films, argon gas flow rate of 30scccm and annealed at 950℃ in the oxygen atmosphere, have the best electrical properties:a field effect mobility of 56.1cm2/V s, an on/off current ratio of 5.1×106 and a threshold voltage of 2.0V. Compared to the single layer structure, the double-active layer structure can improve the electrical properties of TFT, and the mobility of the TFT was 62.1cm2/V s.(3) The In0.67Zn0.33O:Li films were deposited on quartz by magnetron sputtering, and the effect of annealing temperature on the morphology of Ino.67Zno.330:Li thin films was investigated. In0.67Zn0.33O:Li TFTs were fabricated on SiO2/p-Si substrates, the effects of the oxygen gas flow rate, the sputtering power, the active layer thickness and annealing temperature on the electrical properties of TFTs were investigated, respectively. The experimental results shows the TFT with an 30nm In0.67ZnO.330:Li films, no oxygen gas flow rate, sputtering power of 100W and annealed at 950℃,exhibited the best electrical properties:a field effect mobility of 80.4cm2/V s, an on/off current ratio of 4.0×106 and a threshold voltage of 4.1V. The electrical property of the TFT device is one of the best electrical properties in the papers. Without any protection, the mobility of the TFT decreased slightly to 73.1cm2/V s and showed a good stability in the atmosphere.更多还原