溶胶-凝胶法制备氧化锌薄膜晶体管.pdf

华中科技大学硕士学位论文 I 摘要薄膜晶体管是一种利用栅极与源漏电极之间的电场来改变半导体薄膜材料导电能力的绝缘栅型场效应晶体管,是有源矩阵液晶显示技术的核心元件。氧化锌是一种宽禁带、直接带隙化合物半导体材料,在可见光区具有很高的透过率,室温下的电子迁移率较高,且光敏感性弱,制备的器件性能稳定。本文综述了氧化锌和二氧化硅薄膜的基本性质及制备方法。采用溶胶- 凝胶法分别制备了氧化锌和二氧化硅薄膜。通过热重-差热分析得出,二氧化硅薄膜颗粒的生长在 485 ℃左右基本完成, 而氧化锌薄膜晶粒的生长和晶向的形成在 500 ℃左右基本完成。通过 X 射线衍射分析,探讨了不同预热温度对 ZnO 薄膜晶粒取向的影响。通过扫描电子显微镜,对比了不同衬底对薄膜晶粒大小的影响。通过紫外- 可见分光光度计, 分析了不同薄膜层的透过率,拟合了薄膜的光学禁带宽度。本文重点研究了氧化锌薄膜晶体管的制备过程及参数提取方法。采用溶胶- 凝胶法在 ITO 玻璃衬底上制备了氧化锌和二氧化硅薄膜,所得二氧化硅/ 氧化锌复合薄膜的可见光透过率达到 80 % 以上。然后采用磁控溅射法制备 Au 源漏电极,形成了底栅结构的薄膜晶体管。通过半导体器件性能表征,所得薄膜晶体管为 n沟道器件,工作模式为增强型,电流开关比约为 10 4,阈值电压约为 3V ,沟道迁移率约为 cm 2 /Vs 。关键词:氧化锌二氧化硅薄膜晶体管溶胶- 凝胶法华中科技大学硕士学位论文 II Abstract Thin film transistor (TFT) is a kind of insula ted-gate field-effect transistors, which changed the conductivity of the semiconductors via the electric field between the source and drain electrodes. TFT is the ponent in the active matrix liquid crystal display technology. ZnO is a wide-band and direct pound semiconductor with a high transmittance in the visible spectrum. Th e electron mobility in ZnO is large at room temperature, and the light sensitivity is weak; so that, the obtained device is stable. The basic properties and fabrication processes of ZnO and SiO 2films are reviewed in this paper. The sol-gel technique is adopted to deposite the SiO 2and ZnO films. The growth of SiO 2film particles is pleted at 485 ℃, while the growth of ZnOfilm grains and the formation of crystal orientations pleted at 500 ℃ through the Differential Thermal Analysis. The influence of preheating temperature to the crystal orientations is discussed by the X-ray Diffractometer. The grain size on different substrates pared via the Scanning Electronic Microscopic. The tranmittance of films and the optical band gap are studied by the Ultraviolet-visible Spectrophotometer. The fabrication of ZnO TFTs and the extraction of the parameters are investigated. ZnO and SiO 2films are dip-coated on ITO/glass s ubstrates via the sol-gel technique to serve as the channel an